JP7600798B2 - Laminated Molded Body - Google Patents

Description

The present invention relates to a laminated molded product that includes an adhesive resin layer containing a modified polyester elastomer and a gas barrier resin layer.

Laminated molded articles made of gas-barrier resins, such as ethylene-vinyl alcohol copolymers and polyamide resins, and polyolefin resins are widely used in the food packaging field for containers such as films, bottles, and cups, and in the non-food field for industrial piping and hoses, tubes for transporting beverages and medicines, and automobile parts, due to their excellent mechanical properties, safety in food applications, and ability to block gases such as water vapor and oxygen. If it is desired to impart aroma preservation, rigidity, heat resistance, cold resistance, surface printability, etc. to such laminated molded articles, polyester resins are used instead of polyolefin resins, or a polyester resin layer is further laminated onto the laminate.

Since ethylene-vinyl alcohol copolymers and polyamide resins have poor adhesion to polyester resins, a technique is known in which an adhesive layer made of an adhesive resin composition is provided for laminating them.
For example, Patent Document 1 describes an adhesive resin composition comprising a modified polyester elastomer having a polyalkylene ether glycol segment content of 58 to 73% by weight.

On the other hand, in food packaging containing oily contents, industrial hoses, drug delivery tubes, automobile parts, etc. that come into contact with chemicals and solvents under the usage environment, there is a problem that oil, chemicals, and solvents migrate to the interfaces of the resin layers of the laminated molded body constituting the laminated molded body, causing peeling. In addition, in applications where the laminated molded body is exposed to a solvent for a long period of time, the adhesive layer made of the adhesive resin composition may swell and deform due to the solvent, causing deformation and embrittlement of the laminated molded body. For this reason, an adhesive resin composition with excellent solvent resistance is required.
Patent Document 2 describes that an adhesive layer made of a composition containing a modified polyethylene having a specific melt flow rate and density and an unmodified polyethylene has excellent initial adhesive strength and solvent durability.

JP 2002-155135 A JP 2003-73506 A

However, the adhesive resin composition described in Patent Document 1 has excellent adhesiveness, as shown in Comparative Examples 3 to 5 below, but has room for improvement in solvent durability. The adhesive resin composition described in Patent Document 2 has excellent solvent durability, as shown in Comparative Example 6 below, but has insufficient adhesiveness.

The present invention aims to provide a laminated molded product that includes an adhesive resin layer containing a modified polyester-based elastomer and a gas barrier resin layer, and that satisfies adhesion and solvent resistance.

The present inventors have conducted intensive research to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by a laminate molded product comprising an adhesive resin layer and a gas barrier resin layer, the modified polyester-based elastomer being obtained by modifying a polyester-polyether block copolymer with an unsaturated carboxylic acid and/or a derivative thereof, the modified polyester-based elastomer containing a specific ratio of polyalkylene ether glycol segments, and have thus completed the present invention.
That is, the present invention relates to the following.

[1] A laminated molded product including at least an adhesive resin layer containing a modified polyester-based elastomer and a gas barrier resin layer, the modified polyester-based elastomer being a modified polyester-based elastomer obtained by modifying a polyester-based elastomer consisting of a polyester polyether block copolymer consisting of a hard segment containing an aromatic polyester and a soft segment containing a polyalkylene ether glycol segment with an unsaturated carboxylic acid and/or a derivative thereof, and the content of the polyalkylene ether glycol segment in the modified polyester-based elastomer is 36 to 53 mass%.

[2] The laminated molded product described in [1], wherein the adhesive resin layer contains 50% by mass or more of the modified polyester elastomer relative to the total components of the adhesive resin layer.

[3] The laminated molded product according to [1] or [2], wherein the gas barrier resin layer is a resin layer mainly composed of an ethylene-vinyl alcohol copolymer.

[4] The laminate molded product according to any one of [1] to [3], further comprising a polyester resin layer, and the adhesive resin layer is disposed between the gas barrier resin layer and the polyester resin layer.

The present invention provides a laminated molded article that includes an adhesive resin layer containing a modified polyester elastomer and a gas barrier resin layer, and that has both high adhesion and excellent solvent resistance.

The present invention will be described in detail below. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to the contents of the following description as long as it does not exceed the gist of the present invention. The present invention can be modified and implemented as desired without departing from the gist of the present invention.
In the present invention, when "~" is used to express a value with a numerical value or physical property value before and after it, the values before and after it are included in the expression.

In the present invention, the density, melting point, hardness, melt flow rate (MFR), and polyalkylene ether glycol segment content of the resin are values measured as follows.

<Density>
The density is measured by an underwater displacement method in accordance with JIS K7112.

<Melting Point>
The melting point is measured using a differential scanning calorimeter (DSC). Specifically, the temperature is once raised to 300°C to erase the thermal history, then the temperature is lowered to 40°C at a temperature drop rate of 10°C/min, and then the temperature is raised again at a temperature rise rate of 10°C/min to measure, and the temperature at the top of the endothermic peak is taken as the melting point. The unit is °C.

<Hardness>
This is the JIS-D hardness measured by a durometer in accordance with JIS K6253 (D hardness).

<MFR>
The MFR (melt flow rate) of the polyester elastomer and modified polyester elastomer described below is measured at a temperature of 230° C., a load of 2.16 kg, and for 10 minutes in accordance with JIS K 7210. In the measurement, the polyester elastomer and modified polyester elastomer are vacuum-dried in a pellet state at 100° C. for 4 hours to remove the moisture contained therein.
The MFR of the modified polyethylene is measured in accordance with JIS K7210 under conditions of a temperature of 190° C., a load of 2.16 kg, and a time of 10 minutes.

<Content of Polyalkylene Ether Glycol Segment in Modified Polyester Elastomer>
The content of the polyalkylene ether glycol segment in the modified polyester elastomer is calculated based on the chemical shift of the hydrogen spectrum by dissolving a sample in a mixed solvent of deuterated chloroform/hexafluoroisopropanol and measuring the ^{1 H} NMR spectrum at room temperature using a nuclear magnetic resonance apparatus (AVANCE 400 spectrometer manufactured by Bruker Corporation).
When two or more types of modified polyester-based elastomers are used, each modified polyester-based elastomer is used as the subject sample, and each is measured in the same manner as above to calculate the polyalkylene ether glycol segment content, which can then be calculated by proportional calculation based on the blending mass ratio of each modified polyester-based elastomer.
Theoretically, the content of the polyalkylene ether glycol segment in the modified polyester elastomer is the same as the content of the polyalkylene ether glycol segment in the polyester elastomer before modification, i.e., it can be considered that there is no change in the content of the polyalkylene ether glycol segment before and after modification.

The laminate molded product of the present invention is a laminate molded product comprising at least an adhesive resin layer containing a modified polyester-based elastomer and a gas barrier resin layer, the modified polyester-based elastomer being obtained by modifying a polyester-based elastomer consisting of a polyester-polyether block copolymer consisting of a hard segment containing an aromatic polyester and a soft segment containing a polyalkylene ether glycol segment with an unsaturated carboxylic acid and/or a derivative thereof, and characterized in that the content of the polyalkylene ether glycol segment in the modified polyester-based elastomer is 36 to 53 mass%.
Hereinafter, the modified polyester-based elastomer contained in the adhesive resin layer of the present invention may be referred to as the “modified polyester-based elastomer of the present invention”, and the polyester-based elastomer before modification may be simply referred to as the “polyester-based elastomer” or “component (A)”.
In addition, the unsaturated carboxylic acid and/or its derivative used for modifying the polyester-based elastomer may be referred to as "component (B)", and the radical generator used in the modification treatment may be referred to as "component (C)".

The modified polyester elastomer of the present invention is obtained by modifying a polyester elastomer, which is a polyester polyether block copolymer consisting of a hard segment containing an aromatic polyester and a soft segment containing a polyalkylene ether glycol segment, with an unsaturated carboxylic acid and/or a derivative thereof.

In the present invention, modification refers to graft modification of polyester elastomers with unsaturated carboxylic acids and/or derivatives thereof, modification by terminal modification and transesterification reaction, modification by decomposition reaction, etc. Specifically, the sites where unsaturated carboxylic acids and/or derivatives thereof are bonded include terminal functional groups and alkyl chain portions, particularly terminal carboxyl groups, terminal hydroxyl groups, and carbon atoms at the α-position and β-position relative to the ether bond of the polyalkylene ether glycol segment. In particular, it is presumed that many are bonded to the α-position relative to the ether bond of the polyalkylene ether glycol segment.

When a polyester elastomer is modified with an unsaturated carboxylic acid and/or a derivative thereof, a modified polyester elastomer is usually obtained as a composition containing a modified polyester elastomer modified with the polyester elastomer, an unmodified polyester elastomer, the unsaturated carboxylic acid and/or a derivative thereof used in the modification, a radical generator described below, etc. The modified polyester elastomer of the present invention means a modified polyester elastomer composition obtained by such a modification reaction and containing residues of the unmodified polyester elastomer and the unsaturated carboxylic acid and/or a derivative thereof, etc.
In addition, the modified polyester-based elastomer of the present invention may be a mixture of a modified polyester-based elastomer obtained by modifying a polyester-based elastomer and an unmodified polyester-based elastomer, as long as the content of the polyalkylene ether glycol segment specified in the present invention, and preferably the suitable acid modification rate described below, is satisfied.

[mechanism]
The adhesive resin layer according to the present invention contains a modified polyester-based elastomer, and therefore can have sufficient adhesion to a gas barrier resin layer, particularly to an ethylene-vinyl alcohol copolymer or a polyamide-based resin. In addition, since the modified polyester-based elastomer according to the present invention has a polyester as the main skeleton, it has high compatibility with polyester-based resins and high adhesion.
In addition, when the content of the polyalkylene ether glycol segment in the modified polyester elastomer of the present invention is 36 to 53 mass%, it is possible to achieve both adhesiveness and solvent resistance. This is presumably because a large amount of unsaturated carboxylic acid and/or its derivative is bonded to the polyalkylene ether glycol segment in the modified polyester elastomer due to modification. That is, if the modified polyester elastomer contains a sufficient amount of polyalkylene ether glycol segment of 36 mass% or more, the degree of modification (content of unsaturated carboxylic acid component contained in the modified polyester elastomer) is high, and adhesiveness to the gas barrier resin can be sufficiently satisfied. On the other hand, when the content of the polyalkylene ether glycol segment in the modified polyester elastomer is 53 mass% or less and the remaining portion contains a sufficient amount of highly crystalline hard segments, the crystallinity of the modified polyester elastomer is high, and as a result, the solvent resistance is excellent.

[Polyester elastomer]
The polyester elastomer according to the present invention is a polyester-polyether block copolymer comprising a hard segment containing an aromatic polyester and a soft segment containing a polyalkylene ether glycol.
The content of the polyalkylene ether glycol segment in the polyester elastomer according to the present invention is 36 to 53% by mass, preferably 38 to 50% by mass, for the same reasons as in the modified polyester elastomer described below.
As in the case of the modified polyester-based elastomer, when two or more kinds of polyester-based elastomers are used, even if some of the polyester-based elastomers have a polyalkylene ether glycol segment content outside the range of 35 to 53 mass%, it is sufficient as long as the overall polyalkylene ether glycol segment content is within the range of 36 to 53 mass%.

The polyester elastomer preferably has a density of 1.00 to 1.35 g/ ^cm3 , more preferably 1.05 to 1.30 g/ ^cm3 , and even more preferably 1.10 to 1.25 g/ ^cm3 . The density correlates with the polyalkylene ether glycol content, and the higher the polyalkylene ether glycol content, the lower the density. That is, by setting the density to be equal to or higher than the lower limit of the above range, it becomes easier to suppress a decrease in solvent resistance, and by setting the density to be equal to or lower than the upper limit of the above range, it becomes easier to improve adhesion to the gas barrier resin.

The polyester elastomer preferably has a melting point of 145 to 245°C, more preferably 160 to 230°C, and even more preferably 175 to 215°C. By setting the melting point at or above the lower limit of the above range, it becomes easier to prevent the heat resistance from decreasing in the usage environment, and by setting the melting point at or below the upper limit of the above range, it becomes easier to improve the co-extrusion moldability with gas barrier resins that are thermally degraded at high temperatures, such as ethylene-vinyl alcohol copolymers.

The D hardness (JIS-D hardness) of the polyester elastomer is preferably 10 to 80, more preferably 20 to 70, and even more preferably 40 to 60. If the JIS-D hardness is equal to or greater than the lower limit of the above range, the solvent resistance tends to be excellent, and if it is equal to or less than the upper limit of the above range, the flexibility required when made into a laminated molded product such as a film or tube tends to be easily maintained.

In addition, the MFR of the polyester elastomer measured in accordance with JIS K7210 at a temperature of 230°C, a load of 2.16 kg, and for 10 minutes is preferably 0.5 to 300 g/10 min, more preferably 1 to 150 g/10 min, and even more preferably 2 to 75 g/10 min. When the MFR of the polyester elastomer is below the upper limit of the above range, it is easier to increase the melt tension and suppress drawdown during molding, and when it is above the lower limit of the above range, it is easier to suppress deterioration of moldability such as uneven thickness caused by insufficient fluidity.

A polyester-based elastomer consisting of a hard segment containing an aromatic polyester and a soft segment containing a polyalkylene ether glycol can usually be obtained by polycondensing an oligomer obtained by an esterification reaction or transesterification reaction using i) an aliphatic and/or alicyclic diol having 2 to 12 carbon atoms, ii) an aromatic dicarboxylic acid and/or its alkyl ester, and iii) a polyalkylene ether glycol having a number average molecular weight of 400 to 6,000 as raw materials.

i) As the aliphatic and/or alicyclic diol having 2 to 12 carbon atoms, those that are typically used as raw materials for polyesters, particularly polyester-based elastomers, can be used. Examples include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. Among these, 1,4-butanediol and ethylene glycol are preferred, and 1,4-butanediol is particularly preferred. These diols can be used alone or in a mixture of two or more.

ii) As the aromatic dicarboxylic acid, those generally used as raw materials for polyesters, particularly polyester-based elastomers, can be used, such as terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid. Among these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred, with terephthalic acid being particularly preferred. Two or more of these dicarboxylic acids may be used in combination. When using alkyl esters of aromatic dicarboxylic acids, dimethyl esters or diethyl esters of the above dicarboxylic acids are used. Dimethyl terephthalate and 2,6-dimethyl naphthalate are preferred.

iii) Examples of polyalkylene ether glycols include polyethylene glycol, poly(1,2 and 1,3-propylene ether) glycol, poly(tetramethylene ether) glycol, poly(hexamethylene ether) glycol, and poly(decamethylene ether) glycol. Of these, poly(tetramethylene ether) glycol is particularly preferred.

As the polyalkylene ether glycol, one having a number average molecular weight of 400 to 6,000 is usually used, preferably 600 to 4,000, and more preferably 900 to 3,000. By having a number average molecular weight equal to or higher than the lower limit of the above range, it becomes easier to control the degree of modification by the unsaturated carboxylic acid and/or its derivative to a desired range, and there is a tendency that sufficient adhesiveness is easily exhibited. On the other hand, by having a number average molecular weight equal to or lower than the upper limit of the above range, phase separation in the system can be suppressed, and there is a tendency that the deterioration of the physical properties of the obtained polymer can be suppressed. The "number average molecular weight" referred to here is measured by nuclear magnetic resonance (NMR) analysis.
The polyalkylene ether glycol is used so that the content of the polyalkylene ether glycol segment in the polyester elastomer is 36 to 53% by mass, preferably 38 to 50% by mass.

In addition to the above components, a small amount of trifunctional triol or tricarboxylic acid or their esters may be copolymerized into the polyester elastomer, and aliphatic dicarboxylic acids such as adipic acid or their dialkyl esters may also be used as copolymerization components.

As the polyester-based elastomer, commercially available products may be used, such as "TEFABLOCK (registered trademark)" manufactured by Mitsubishi Chemical Corporation, "PELPRENE (registered trademark)" manufactured by Toyobo Co., Ltd., and "HYTREL (registered trademark)" manufactured by DuPont-Toray Co., Ltd.

The polyester elastomer may be one type, or two or more types having different monomer compositions, physical properties, etc. may be subjected to modification with the unsaturated carboxylic acid and/or a derivative thereof.
As described above, when two or more kinds of polyester-based elastomers are used, even if some of the polyester-based elastomers have a polyalkylene ether glycol segment content outside the range of 35 to 53 mass%, it is sufficient as long as the overall polyalkylene ether glycol segment content is within the range of 36 to 53 mass%.

[Unsaturated carboxylic acid and/or its derivative]
The unsaturated carboxylic acid used to modify the polyester elastomer is preferably an α,β-ethylenically unsaturated carboxylic acid, such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, tetrahydrofumaric acid, itaconic acid, citraconic acid, crotonic acid, or isocrotonic acid. Examples of derivatives of unsaturated carboxylic acids include acid anhydrides and carboxylates of these unsaturated carboxylic acids, and may further include derivatives such as acid halides, amides, and imides. Of these derivatives, acid anhydrides are preferred.

Among these, maleic acid and/or its anhydride are particularly suitable as the unsaturated carboxylic acid and/or its derivative. A plurality of these compounds may be used in combination. Furthermore, so-called vinyl silanes such as vinyltrimethoxysilane may be used in combination with the unsaturated carboxylic acid and/or its derivative.

[Radical Generator]
When the polyester elastomer is modified with an unsaturated carboxylic acid and/or a derivative thereof, a radical generator is usually used to carry out a radical reaction.
Examples of the radical generator include peroxy esters, dialkyl peroxides, diacyl peroxides, hydroperoxides, and ketone peroxides. Of these, dibenzoyl peroxide and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane are preferably used as diacyl peroxides. These radical generators may be appropriately selected depending on the type of polyester elastomer, the type of unsaturated carboxylic acid and/or its derivative, and the modification conditions, and two or more types may be used in combination. The radical generator may be added by dissolving it in an organic solvent or the like.

[Method of producing modified polyester elastomer]
The modified polyester elastomer of the present invention may be produced by any known method, such as a melt-kneading reaction method, a solution reaction method, or a suspension dispersion reaction method, but the melt-kneading reaction method is usually preferred.

In the case of the melt-kneading reaction method, the components (A) to (C) are mixed uniformly in a predetermined mixing ratio and then melt-kneaded. For mixing, a Henschel mixer, a ribbon blender, a V-type blender, or the like can be used, and for melt-kneading, a single-screw or twin-screw extruder, a roll, a Banbury mixer, a kneader, a Brabender mixer, or the like can usually be used.
The melt kneading is carried out at a temperature of usually 100° C. or higher, preferably 120° C. or higher, more preferably 150° C. or higher, and usually 300° C. or lower, preferably 280° C. or lower, more preferably 250° C. or lower, so as to prevent thermal degradation of the resin.

The amount of unsaturated carboxylic acid and/or its derivative used in modification as component (B) is usually 0.01 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and usually 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 1 part by mass or less, per 100 parts by mass of the polyester elastomer as component (A). By setting the amount of unsaturated carboxylic acid and/or its derivative to be equal to or more than the lower limit, sufficient modification can be easily performed, and by setting the amount to be equal to or less than the upper limit, it is not only economical but also makes it easier to prevent the unsaturated carboxylic acid and/or its derivative that did not contribute to the modification from acting as an impurity and reducing the adhesiveness.

The amount of the radical generator of component (C) is usually 0.001 parts by mass or more, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and usually 4 parts by mass or less, preferably 3 parts by mass or less, more preferably 2 parts by mass or less, based on 100 parts by mass of the polyester elastomer of component (A). When the amount of the radical generator is equal to or more than the lower limit, the modification reaction is easily caused, and when the amount is equal to or less than the lower limit, the material strength is prevented from being significantly reduced due to the promotion of the reduction in molecular weight (reduction in viscosity) of component (A). That is, in this modification reaction, a graft polymerization reaction in which component (B) an unsaturated carboxylic acid and/or its derivative is added to component (A) mainly occurs, but a decomposition reaction also occurs, and the molecular weight of the resulting modified product is reduced due to the decomposition, resulting in a reduction in material strength. If the amount of the radical generator used is too large, the graft polymerization reaction is easily caused, but at the same time, the decomposition reaction leading to such a reduction in molecular weight is also easily caused, which is not preferable.

The product obtained by this modification reaction can be used as the modified polyester elastomer of the present invention as is for forming an adhesive resin layer, as described below.

[Polyalkylene Ether Glycol Segment Content of Modified Polyester Elastomer]
The content of the polyalkylene ether glycol segment in the modified polyester elastomer of the present invention is 36 to 53% by mass. When the content of the polyalkylene ether glycol segment in the modified polyester elastomer is 36 to 53% by mass, the adhesiveness and solvent resistance can be satisfied when the modified polyester elastomer is used as an adhesive resin layer. When the content of the polyalkylene ether glycol segment in the modified polyester elastomer exceeds the upper limit of the above range, the crystallinity tends to decrease and the solvent resistance tends to be poor. When the content of the polyalkylene ether glycol segment in the modified polyester elastomer is less than the lower limit of the above range, the low-temperature impact resistance and the adhesiveness to ethylene-vinyl alcohol copolymers and polyamide resins tend to decrease. From this viewpoint, the lower limit of the content of the polyalkylene ether glycol segment in the modified polyester elastomer of the present invention is preferably 38% by mass or more. On the other hand, the upper limit of the content of the polyalkylene ether glycol segment in the modified polyester elastomer of the present invention is preferably 50% by mass or less.

The polyalkylene ether glycol segment content of the modified polyester elastomer here refers to the polyalkylene ether glycol segment content of the modified polyester elastomer as a whole. In other words, for example, when two or more modified polyester elastomers are mixed and used, even if one of them has a polyalkylene ether glycol segment content outside the range of 36 to 53% by mass, it is acceptable as long as the polyalkylene ether glycol segment content of the modified polyester elastomer as a mixture is within the range of 35 to 53% by mass.

[Acid modification rate of modified polyester elastomer]
The modified polyester elastomer of the present invention may be produced by using an unsaturated carboxylic acid and/or its derivative and a radical generator in the above-mentioned suitable blending amount relative to the polyester elastomer, and the acid modification rate is not particularly limited, but is preferably 0.01 to 8. If the acid modification rate is equal to or higher than the lower limit of the above range, sufficient adhesion to the gas barrier resin layer can be obtained. If the acid modification rate is equal to or lower than the upper limit of the above range, discoloration due to the unsaturated carboxylic acid and/or its derivative can be suppressed. The lower limit of the acid modification rate is more preferably 0.1 or more, even more preferably 0.15 or more, and particularly preferably 0.16 or more. The upper limit of the acid modification rate is more preferably 4 or less, and even more preferably 0.8 or less.
The acid modification rate of the modified polyester elastomer is measured and calculated by the method described in the Examples section below.

[Adhesive resin layer]
The adhesive resin layer according to the present invention contains the modified polyester elastomer of the present invention in an amount of preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, based on the total components of the adhesive resin layer. If the content of the modified polyester elastomer is equal to or more than the lower limit, the adhesion to the gas barrier resin layer and the solvent resistance can be sufficiently improved. There is no particular upper limit to the content of the modified polyester elastomer, and it may be 100% by mass.

In addition to the modified polyester elastomer of the present invention, the adhesive resin layer of the present invention may contain any component (hereinafter, sometimes referred to as "other component") according to the purpose, as long as the effect of the present invention is not significantly hindered. The other components may be used alone or in any combination and ratio of two or more.

Specific examples of other components include resin components and rubber components other than the modified polyester elastomer of the present invention (polyester resins such as polyethylene terephthalate and polybutylene terephthalate, styrene resins such as polystyrene, polyolefin resins, and acrylic/methacrylic resins such as polymethyl methacrylate resins), heat stabilizers, weather stabilizers (antioxidants, light stabilizers, UV absorbers, etc.), flame retardants, antiblocking agents, slip agents, antistatic agents, fillers (inorganic and/or organic fillers, etc.), processing aids, plasticizers such as paraffin oil, crystal nucleating agents, impact modifiers, compatibilizers, neutralizers for catalyst residues, carbon black, colorants (pigments, dyes, etc.), antifogging agents, crosslinking agents, crosslinking aids, chain extenders, dispersants, antibacterial agents, antiviral agents, and fluorescent brighteners. Among these, it is preferable to add at least one of various antioxidants such as phenols, phosphites, thioethers, and aromatic amines. When these antioxidants are used, their content is not limited, but is usually 0.01% by mass or more, preferably 0.05% by mass or more, and usually 5% by mass or less, preferably 2% by mass or less, based on the total components constituting the adhesive resin layer.

[Gas barrier resin layer]
The gas barrier resin layer according to the present invention is preferably a resin layer mainly composed of an ethylene-vinyl alcohol copolymer. The ethylene-vinyl alcohol copolymer is produced by saponifying an ethylene-vinyl acetate copolymer in the presence of alcohol. As the ethylene-vinyl alcohol copolymer constituting the gas barrier resin layer, an ethylene-vinyl acetate copolymer having an ethylene content of preferably 15 to 65 mol%, more preferably 20 to 50 mol%, which is saponified to a degree of saponification of preferably 50% or more, more preferably 90% or more, is preferably used.
Examples of commercially available products of such ethylene-vinyl alcohol copolymers include "Soarnol (registered trademark)" manufactured by Mitsubishi Chemical Corporation, "Eval (registered trademark)" manufactured by Kuraray Co., Ltd., and "Evasin" manufactured by Chang Chun Group.

The gas barrier resin layer may contain only one type of ethylene-vinyl alcohol copolymer, or may contain two or more types with different degrees of saponification or monomer compositions, but it is preferable that the gas barrier resin layer contains ethylene-vinyl alcohol copolymer as the main component in an amount of usually 50% by mass or more, particularly 65 to 100% by mass, and especially 75 to 100% by mass. If the ethylene-vinyl alcohol copolymer content in the gas barrier resin layer is equal to or higher than the above lower limit, excellent gas barrier properties are obtained.

Components other than the ethylene-vinyl alcohol copolymer that may be contained in the gas barrier resin layer are not particularly limited, but include resin components such as polyolefin resins, styrene resins, and acrylic/methacrylic resins, as well as various additives such as heat stabilizers, weather stabilizers (antioxidants, light stabilizers, UV absorbers, etc.), flame retardants, antiblocking agents, slip agents, fillers (inorganic and/or organic fillers, etc.), processing aids, plasticizers such as paraffin oil, crystal nucleating agents, impact modifiers, compatibilizers, neutralizers for catalyst residues, and colorants (pigments, dyes, etc.).

[Polyester-based resin layer]
The laminated molded product of the present invention may further include a layer of a polyester-based resin in order to impart functionality such as aroma preservation, rigidity, heat resistance, cold resistance, surface printability, etc. The polyester-based resin is produced by dehydration condensation of a polyvalent carboxylic acid and a polyalcohol, and examples of the polyester-based resin include those obtained by polycondensation of a dicarboxylic acid and a diol.

The above-mentioned carboxylic acids are not particularly limited, but examples thereof include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenyl ether-4,4-dicarboxylic acid, and naphthalene-1,4- or 2,6-dicarboxylic acid, aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, and undecadicarboxylic acid, and alicyclic dicarboxylic acids such as hexahydroterephthalic acid.

The diol is not particularly limited, but examples thereof include alicyclic glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, and neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, and aromatic dihydroxy compounds such as bisphenol A.

Examples of the polyester resins include polyethylene terephthalate (PET), PET copolymers, polybutylene terephthalate, polyethylene naphthalate, polycyclohexyne terephthalate, and polyester elastomers. These polyester resins can be used alone or in the form of a mixture of multiple polyester resins.

[Other layers]
The laminated molded product of the present invention may further have other layers in addition to those described above. Examples of the other layers include layers made of resins other than the constituent resins of the adhesive resin layer, gas barrier resin layer, and polyester-based resin layer described above, and the substrate layer described below.

The resins constituting the layer made of other resins are not limited, and specific examples include the resins listed as other components in the adhesive resin layer described above, polyamide resins such as nylon 66 and nylon 11, cyclic polyolefin resins, polyvinyl chloride, polyvinylidene chloride, and thermoplastic resins such as polycarbonate resins, but polyolefin resins and polyamide resins are preferred from the viewpoint of excellent co-extrudability with the modified polyester elastomer of the present invention.

In addition, the adhesive resin layer containing the modified polyester elastomer of the present invention has excellent adhesion and solvent resistance, so it can also be bonded to a base material layer such as a metal and/or resin sheet via this adhesive resin layer.

The form of the substrate layer is not limited to a film or sheet, and may be a woven or nonwoven fabric. The substrate layer may have a single-layer structure or a multi-layer structure. The method for producing a substrate having a multi-layer structure is not particularly limited, and examples include a co-extrusion film method, a dry lamination method, a wet lamination method, a hot melt lamination method, an extrusion lamination method, and a thermal lamination method.

The laminate molded product of the present invention may have any layer other than the adhesive resin layer containing the modified polyester-based elastomer of the present invention, the gas barrier resin layer, the polyester-based resin layer, the layer of other resins, and the substrate layer made of the above-mentioned metal or the like.

[Laminated Molded Product]
The laminated molded article of the present invention is a laminated molded article including an adhesive resin layer containing the modified polyester-based elastomer of the present invention and a gas barrier resin layer, and is preferably a laminated molded article having two or more layers laminated therein. Among them, it is preferable to have a gas barrier resin layer mainly composed of an ethylene-vinyl alcohol copolymer and, if necessary, the above-mentioned polyester-based resin layer. In particular, a laminated molded article having a polyester-based resin layer, an adhesive resin layer containing the modified polyester-based elastomer of the present invention, and a gas barrier resin layer laminated in this order is preferably used. In this case, it is also possible to make a laminated molded article having two or more layers laminated in some layers, such as a polyester-based resin layer/adhesive resin layer/gas barrier resin layer/adhesive resin layer/polyester-based resin layer.

The laminated molded article of the present invention may further include layers of the other resins and/or metals described above, and may be formed into a laminated molded article having three or more layers laminated therein.
The laminated molded article of the present invention may be in the form of a laminated film, a laminated sheet, a laminated tube, etc. Here, the terms "film" and "sheet" both mean planar molded articles and have the same meaning.

The total thickness of the laminated molded product of the present invention is not particularly limited and can be adjusted appropriately depending on the application. The total thickness of the laminated molded product of the present invention is preferably 20 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, and is preferably 10 mm or less, more preferably 6 mm or less, and even more preferably 1 mm or less. By having the thickness within the above range, it becomes easy to manufacture a laminated molded product without wrinkles, cracks, etc.

The thickness of the adhesive resin layer containing the modified polyester elastomer of the present invention is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 1 mm or less, more preferably 0.5 mm or less, and even more preferably 0.1 mm or less.
The thickness of the gas barrier resin layer is generally 0.002 to 1 mm.
The thickness of the polyester resin layer is generally 0.01 to 3 mm.

[Method of manufacturing laminated molded product]
The laminated molded article of the present invention can be produced by various conventionally known methods. For example, the laminated molded article may be produced by a co-extrusion method in which individual molten resins melted in an extruder are fed into a multi-layer die and laminated in the die to produce an inflation film, cast film, sheet, tube, pipe, or bottle, or by co-injection molding in which individual molten resins are sequentially injected into the same die, or by co-extrusion lamination of an unstretched test tube-shaped parison or the like.

The present invention will be explained in more detail below using examples, but the present invention is not limited to the following examples as long as it does not exceed the gist of the invention. The various manufacturing conditions and evaluation result values in the following examples are meant as preferred upper or lower limit values in the embodiments of the present invention, and the preferred range may be a range defined by a combination of the above-mentioned upper or lower limit values and the values of the following examples or values between the examples.

〔raw materials〕
The raw materials used in the production of laminated molded bodies in the following Examples and Comparative Examples are as follows.

[Adhesive resin layer]
<Component (A)>
A-1: Polyester-based elastomer A polyester-polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 1,000 as a soft segment, in which the content of polytetramethylene ether glycol segments in the copolymer was 45 mass % (density: 1.16 g/cm ³ , melting point: 189.9°C, JIS-D hardness: 43, MFR: 21 g/10 min) was used.
A-2: Polyester-based elastomer A polyester-polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 1,000 as a soft segment, in which the content of polytetramethylene ether glycol segments in the copolymer was 32 mass % (density: 1.20 g/cm ³ , melting point: 205.1°C, JIS-D hardness: 54, MFR: 22 g/10 min) was used.
A'-1: Polyester-based elastomer A polyester-polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 2,000 as a soft segment, in which the content of polytetramethylene ether glycol segments in the copolymer was 73 mass % (density: 1.07 g/cm ³ , melting point: 160.1°C, JIS-D hardness: 24, MFR: 20 g/10 min) was used.
A'-2: Polyester-based elastomer A polyester-polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 2,000 as a soft segment, in which the content of polytetramethylene ether glycol segments in the copolymer was 64 mass % (density: 1.10 g/cm ³ , melting point: 186.1°C, JIS-D hardness: 31, MFR: 21 g/10 min) was used.
A'-3: Polyester-based elastomer A polyester-polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 1,000 as a soft segment, in which the content of polytetramethylene ether glycol segments in the copolymer was 61 mass % (density: 1.10 g/cm ³ , melting point: 160.6°C, JIS-D hardness: 38, MFR: 17 g/10 min) was used.
A'-4: Polyester-based elastomer A polyester-polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 1,000 as a soft segment, in which the content of polytetramethylene ether glycol segments in the copolymer was 20 mass % (density: 1.26 g/cm ³ , melting point: 220.0°C, JIS-D hardness: 60, MFR: 60 g/10 min) was used.

<Component (B)>
B: Unsaturated carboxylic acid anhydride "Maleic anhydride (special grade reagent)" (particle size 5 to 10 mm) manufactured by Wako Pure Chemical Industries, Ltd. was crushed in a small mixer to a particle size of 1 mm or less and used.

<Component (C)>
C: Benzoyl peroxide "Niper (registered trademark) BMTK-40" manufactured by Nippon Oil & Fats Co., Ltd. was used.

<Additives>
X: A phenol-based antioxidant "Irganox 1010 (registered trademark)" manufactured by BASF was used.

[Adhesive resin layer not containing modified polyester elastomer]
Acid-modified polyethylene "Modic (registered trademark) H501E" (MFR: 0.8 g/10 min, density: 0.92 g/cm ³ ) manufactured by Mitsubishi Chemical Corporation was used.

[Gas barrier resin layer]
Ethylene-vinyl alcohol copolymer (EVOH)
"EVAL (registered trademark) L171B" manufactured by Kuraray Co., Ltd. was used.

[Polyester resin]
Mitsubishi Chemical Corporation's "TEFABLOCK (registered trademark) B1921" was used.

[Evaluation method]
In the examples and comparative examples, physical properties were evaluated by the methods described below.

[Polyalkylene Ether Glycol Segment Content in Polyester-Based Elastomer and Modified Polyester-Based Elastomer]
The polyalkylene ether glycol content in the polyester elastomer and the modified polyester elastomer was measured according to the method described above.

[Acid modification rate]
The acid modification ratio is the content of unsaturated carboxylic acid components in the modified polyester elastomer when measured with an infrared spectrometer (JASCOFT/IR610, manufactured by JASCO Corporation). The acid modification ratio was determined by measuring the ratio of the absorption characteristic of the unsaturated carboxylic acid and/or its derivatives (1900 to 1600 cm ⁻¹ ) to the absorption characteristic of the aromatic rings in the hard segments (1000 to 800 cm ⁻¹ ) in a sample obtained by press-molding pellets of the modified polyester elastomer into a sheet having a thickness of 20 to 50 μm at 230° C.

[Measurement of swelling degree]
The obtained modified polyester elastomer or comparative acid-modified polyethylene was injection molded at a melt temperature of 240°C and a mold temperature of 40°C to obtain test pieces with a length of 80 mm, a width of 10 mm and a thickness of 4 mm. These were then immersed in a mixed liquid of equal amounts (by volume) of isooctane/toluene at 60°C for 168 hours, and the swelling degree (%) was calculated using the following formula.
Swelling degree (%)=[{W ₁ −W ₀ }/W ₀ ]×100
Weight of test piece before immersion: W ₀ (g)
Weight of test piece after immersion: W ₁ (g)
If the swelling degree is 40% or less, the deformation and embrittlement of the laminated molded body can be suppressed and it was evaluated as being practical.

[Measurement of adhesive strength of laminated molded product]
Generally, an interlaminar strength of a laminate of 2N/15mm or more is considered to be sufficient for practical use.
<Adhesive strength before immersion in solvent>
The five-layer film obtained in each example was cut into a strip of 15 mm width parallel to the molding direction to prepare a test piece, and a T-peel test was performed at a speed of 300 mm/min in a constant temperature atmosphere of 23° C. to measure the adhesive strength. Here, the adhesive strength in Examples 1 to 3 and Comparative Examples 1 to 5 is the adhesive strength at the interface between the ethylene-vinyl alcohol copolymer layer and the adhesive resin layer. The adhesive strength in Comparative Example 6 is the adhesive strength at the interface between the polyester resin layer and the adhesive resin layer.
<Adhesive strength after immersion in solvent>
For the five-layer film obtained in each example, a strip-shaped test piece prepared in the same manner as above was immersed in a mixture of equal amounts (volume) of isooctane/toluene at 60°C for 168 hours, and within 5 minutes after removal, a T-peel test was performed at a speed of 300 mm/min in a constant temperature atmosphere of 23°C to measure the adhesive strength. As above, the adhesive strengths of Examples 1 to 3 and Comparative Examples 1 to 5 are the adhesive strengths at the interface between the ethylene-vinyl alcohol copolymer layer and the adhesive resin layer. The adhesive strength of Comparative Example 6 is the adhesive strength at the interface between the polyester resin layer and the adhesive resin layer.

[Example 1]
<Production of Modified Polyester Elastomer>
As shown in Table 1, 100 parts by mass of polyester elastomer A-1, 0.5 parts by mass of B, 0.1 parts by mass of C, and 0.1 parts by mass of X were used, and these were dry blended and mixed, and melt kneaded using a twin-screw extruder (manufactured by Nippon Steel Corporation, TEX25αIII, D=25 mmφ, L/D=53) at a set temperature of 180 to 240° C., a screw rotation speed of 200 to 400 rpm, and an extrusion rate of 15 to 30 kg/h, and pellets of modified polyester elastomer were obtained by strand cutting.
The degree of swelling of this modified polyester elastomer was measured.

<Production of laminated molded body>
A multilayer film molding machine (Pla Giken Co., Ltd.) with a 4-type 5-layer multi-manifold type T-die with a width of 320 mm was used to produce a 5-layer film as a laminated molded product of polyester resin layer/adhesive resin layer made of modified polyester elastomer/ethylene-vinyl alcohol copolymer layer/adhesive resin layer made of modified polyester elastomer/polyester resin layer. The temperature of the T-die was set to 250°C, the molding speed was 10 m/min, the cast roll temperature was 30°C, and a film with a total thickness of 400 μm was obtained with the thicknesses of the individual layers being 140 μm/40 μm/40 μm/40 μm/140 μm.
The adhesive strength of the resulting five-layer film was measured.

The above measurement results are shown in Table 1.

[Examples 2 to 3, Comparative Examples 1 to 5]
In the production of the modified polyester elastomer, modified polyester elastomers were obtained in the same manner as in Example 1, except that the ingredients were blended as shown in Table 1, and laminated molded articles were produced in the same manner, and measurements were carried out for each. The results are shown in Table 1.

[Comparative Example 6]
A laminate was produced in the same manner as in Example 1, except that an acid-modified polyethylene "Modic H501E" was used in the adhesive resin layer instead of the modified polyester elastomer, and the adhesive strength was measured. The results are shown in Table 1.

From Table 1, it can be seen that Examples 1 to 3, which are specific examples of the modified polyester-based elastomer of the present invention, exhibit high adhesion to the ethylene-vinyl alcohol copolymer and the polyester-based resin layer while also exhibiting good solvent durability.
In contrast, in Comparative Examples 1 and 2 in which the content of polyalkylene ether glycol segments in the modified polyester elastomer was lower than the range specified in the present invention, the acid modification rate was low and both the adhesion and solvent durability were poor.
In Comparative Examples 3 to 5, in which the content of polyalkylene ether glycol segments in the modified polyester elastomer is higher than the range specified in the present invention, the solvent durability is poor.
In Comparative Example 6, in which acid-modified polyethylene was used, no adhesiveness was obtained.

Claims (3)

A laminated molded product comprising at least an adhesive resin layer containing a modified polyester-based elastomer and a gas barrier resin layer,
The modified polyester-based elastomer is a modified polyester-based elastomer obtained by modifying a polyester-based elastomer consisting of a polyester-polyether block copolymer composed of a hard segment containing an aromatic polyester and a soft segment containing a polyalkylene ether glycol segment with an unsaturated carboxylic acid and/or a derivative thereof, and the content of the polyalkylene ether glycol segment in the modified polyester-based elastomer is 36 to 53 mass %,
the adhesive resin layer contains the modified polyester-based elastomer in an amount of 50% by mass or more based on the total components of the adhesive resin layer,
The gas barrier resin layer comprises any one selected from an ethylene-vinyl alcohol copolymer and a polyamide-based polymer . 2. The laminate according to claim 1 , wherein the gas barrier resin layer is a resin layer containing an ethylene-vinyl alcohol copolymer as a main component. The laminate molded product according to claim 1 or 2 , further comprising a polyester - based resin layer, the adhesive resin layer being disposed between the gas barrier resin layer and the polyester-based resin layer.