JP7147195B2 - Adhesive resin composition, laminate and molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive resin composition having excellent interlayer adhesion, and more particularly, to a biodegradable adhesive resin composition, and a laminate and molded article using this adhesive resin composition. Regarding.

Plastics are widely used as packaging materials because of their excellent moldability, strength, water resistance, transparency, and the like. Plastics used for such packaging materials include polyolefin resins such as polyethylene and polypropylene, vinyl resins such as polystyrene and polyvinyl chloride, and aromatic polyester resins such as polyethylene terephthalate. These plastics are biodegradable. Poor durability, if discarded in the natural world after use, it may remain for a long time and cause environmental destruction, such as spoiling the landscape.

On the other hand, in recent years, biodegradable resins, which are biodegradable or hydrolyzable in soil or water and are useful for preventing environmental pollution, have attracted attention and are being put to practical use. Examples of such biodegradable resins include aliphatic carboxylic acid units such as polybutylene succinate (hereinafter sometimes abbreviated as PBS) and polybutylene succinate adipate (hereinafter sometimes abbreviated as PBSA). Aliphatic oxycarboxylic acid resins such as aliphatic polyester resins and polylactic acid (hereinafter sometimes abbreviated as PLA) containing group diol units, aromatic dicarboxylic acid units such as polybutylene adipate terephthalate, aliphatic dicarboxylic acid units and aromatic-aliphatic copolyester resins having aliphatic diol units.

However, since these resins have insufficient oxygen gas barrier properties, they cannot be used alone as packaging materials for contents such as foods and medicines that are likely to deteriorate due to oxidation. Therefore, an adhesive layer obtained by graft polymerizing an α,β-unsaturated carboxylic acid or its anhydride to the above-mentioned biodegradable polyester resin is placed on one side of the layer composed of these biodegradable resins. Therefore, a method of laminating a polyvinyl alcohol-based resin layer that has excellent gas barrier properties and is also biodegradable has been proposed (see, for example, Patent Document 1).

JP 2013-212682 A

Aliphatic polyester resins, aliphatic oxycarboxylic acid resins or aromatic-aliphatic copolymer polyester resins and polyvinyl alcohol resins have greatly different surface properties, so the laminate described in Patent Document 1 is biodegradable. However, an adhesive layer obtained by graft polymerization of an α,β-unsaturated carboxylic acid or an anhydride thereof to a polyether-based resin has not been able to provide a sufficiently satisfactory interlaminar adhesive strength for practical use. In addition, regarding the aromatic-aliphatic copolyester resin, the interlaminar adhesive strength varies greatly depending on the type of aromatic-aliphatic copolyester resin used, so it is necessary to stably express high strength. was desired.

The object of the present invention is the interlaminar adhesion strength for both biodegradable resin layers such as aliphatic polyester resins, aliphatic oxycarboxylic acid resins, and aromatic-aliphatic copolyester resins and polyvinyl alcohol resin layers. The object is to provide an adhesive resin composition having a sufficiently high adhesive strength and stably exhibiting adhesive strength, and a laminate and a molded article using this adhesive resin composition.

As a result of intensive research to solve the above problems, the present inventors have found that among biodegradable resins, aromatic-aliphatic polyester resins are obtained by graft modification with unsaturated carboxylic acids and / or derivatives thereof. A modified polyester resin having a specific acid value is an adhesive resin composition that exhibits stable interlayer adhesion strength to both a biodegradable resin layer and a polyvinyl alcohol layer. was completed.
That is, the gist of the present invention is as follows.

[1] An aromatic-aliphatic copolymer polyester resin (a) containing an aliphatic and/or alicyclic diol unit, an aliphatic and/or alicyclic dicarboxylic acid unit and an aromatic dicarboxylic acid unit is added to an unsaturated carboxylic acid An adhesive resin composition containing a modified polyester resin (A) graft-modified with an acid and/or a derivative thereof, wherein the modified polyester resin (A) has an acid value of 40 equivalents/ton or more. Adhesive resin composition.

[2] The adhesive resin composition according to [1], wherein the aromatic-aliphatic copolymer polyester resin (a) is biodegradable.

[3] The adhesive resin composition according to [1] or [2], wherein the aromatic-aliphatic copolyester resin (a) is polybutylene adipate terephthalate.

[4] The amount of the unsaturated carboxylic acid and / or derivative thereof as a modifier is 0.01 parts by mass to 3 parts by mass with respect to 100 parts by mass of the aromatic-aliphatic copolymer polyester resin (a) The adhesive resin composition according to any one of [1] to [3], which is a part.

[5] A laminate comprising an adhesive layer made of the adhesive resin composition according to any one of [1] to [4].

[6] A solid-phase pressure-molded article comprising an adhesive layer made of the adhesive resin composition according to any one of [1] to [4].

[7] A food packaging material comprising the molded article according to [6].

The adhesive resin composition of the present invention includes both a biodegradable resin layer such as an aliphatic polyester resin, an aliphatic oxycarboxylic acid resin, and an aromatic-aliphatic copolyester resin and a polyvinyl alcohol resin layer. The interlayer adhesive strength against is sufficiently high, and the adhesive strength can be stably expressed.

The aromatic-aliphatic copolyester resin (a), which is the base resin of the modified polyester resin (A), which is the adhesive component of the adhesive resin composition of the present invention, may itself be biodegradable. The adhesive resin composition of the present invention containing such biodegradable components can be used to produce biomass such as aliphatic polyester resins, aliphatic oxycarboxylic acid resins, and aromatic-aliphatic copolymer polyester resins. The degradable resin layer and the polyvinyl alcohol-based resin layer can be laminated and integrated to form a biodegradable laminate and molded article, and degradability in the natural environment can be expected.

Laminates using an adhesive layer containing the adhesive resin composition of the present invention, stretched films thereof, and the like are used as meat packaging films for ham and sausages, food packaging materials such as coffee capsule containers, pharmaceuticals, quasi-drugs, It can be expected to be suitably used as a medical packaging material for cosmetics, medical devices, regenerative medicine products, and the like.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are examples (representative examples) of embodiments of the present invention, and the present invention is not limited to the following description. The present invention can be arbitrarily modified and implemented without departing from the gist thereof. Further, in this specification, 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.

[Adhesive resin composition]
The adhesive resin composition of the present invention is an aromatic-aliphatic copolymer polyester resin containing an aliphatic and / or alicyclic diol unit, an aliphatic and / or alicyclic dicarboxylic acid unit and an aromatic dicarboxylic acid unit An adhesive resin composition containing a modified polyester resin (A) obtained by graft-modifying (a) with an unsaturated carboxylic acid and/or a derivative thereof, wherein the modified polyester resin (A) has an acid value of It is characterized by being 40 equivalents/ton or more.

<Aromatic-aliphatic copolymer polyester resin (a)>
The aromatic-aliphatic copolyester resin (a) used in the present invention essentially comprises an aliphatic and/or alicyclic diol unit, an aliphatic and/or alicyclic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit. Ingredients.

The aliphatic or alicyclic diol unit contained in the aromatic-aliphatic copolyester resin (a) is represented by the following formula (1), and the aliphatic and/or alicyclic dicarboxylic acid unit is represented by the following formula ( 2), and the aromatic dicarboxylic acid unit is preferably represented by the following formula (3).
-OR ¹ -O- (1)
-OC-R ² -CO- (2)
-OC-R ³ -CO- (3)
(In the above formula (1), R ¹ represents a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group, and in formula (2), R ² is a direct bond, a divalent aliphatic hydrocarbon represents a hydrogen group or a divalent alicyclic hydrocarbon group, and in formula ( ³ ), R3 represents a divalent aromatic hydrocarbon group.)

The diol component that gives the diol unit of formula (1) usually has 2 to 10 carbon atoms, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexane. Among them, ethylene glycol and 1,4-butanediol are preferred, and 1,4-butanediol is particularly preferred.

The dicarboxylic acid component that gives the carboxylic acid unit of formula (2) usually has from 2 to 10 carbon atoms. Examples of aliphatic dicarboxylic acid components include succinic acid, adipic acid, suberic acid, sebacine acid, dodecanedioic acid, and the like, with succinic acid and adipic acid being preferred.

Examples of the aromatic dicarboxylic acid component that provides the aromatic dicarboxylic acid unit of formula (3) include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc. Among them, terephthalic acid and isophthalic acid are preferred, and terephthalic acid is particularly preferred. .

Two or more kinds of each of the diol component, the dicarboxylic acid component, and the aromatic dicarboxylic acid component can be used.

The aromatic-aliphatic copolymer polyester resin (a) used in the present invention preferably has biodegradability. In order to exhibit biodegradability, the aromatic-aliphatic copolymer polyester resin ( Aliphatic chains must be present between the aromatic rings in a). Therefore, the amount of aromatic dicarboxylic acid units in the aromatic-aliphatic copolymer polyester resin (a) is preferably It is 5 mol % or more, preferably 10 mol % or more, particularly preferably 15 mol % or more, while preferably 50 mol % or less, more preferably 48 mol % or less. If this amount is too small, the effect of improving mechanical strength such as tear strength tends to decrease when a film is formed from the aromatic dicarboxylic acid unit. On the other hand, if it is too much, the biodegradability tends to be insufficient.

The aromatic-aliphatic copolyester resin (a) used in the present invention may further contain an aliphatic oxycarboxylic acid unit.
Specific examples of aliphatic oxycarboxylic acid components that provide aliphatic oxycarboxylic acid units include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, mixtures thereof, and the like. Alternatively, they may be lower alkyl esters or intramolecular esters thereof. Moreover, when optical isomers are present in these compounds, they may be D-, L-, or racemic isomers, and may be solid, liquid, or aqueous solution. Preferred among these are lactic acid and glycolic acid. These aliphatic oxycarboxylic acid components can be used singly or as a mixture of two or more.

The amount of this aliphatic oxycarboxylic acid unit is usually 0 mol% or more, preferably 0.01 mol% or more in all structural units constituting the aromatic-aliphatic copolymer polyester resin (a), On the other hand, it is usually 30 mol % or less, preferably 20 mol % or less.

Urethane bonds, amide bonds, carbonate bonds, ether bonds and the like can be introduced into the aromatic-aliphatic copolyester resin (a) within a range that does not affect biodegradability.

The aromatic-aliphatic copolyester resin (a) used in the present invention can be produced by a known method. For example, when introducing a dicarboxylic acid component and a diol component including the above-described aliphatic dicarboxylic acid component and aromatic dicarboxylic acid component, and optionally an aliphatic oxycarboxylic acid component and a trifunctional or higher component, is a general method of melt polymerization such as conducting an esterification reaction and / or transesterification reaction between a dicarboxylic acid unit including those components and a diol component and then conducting a polycondensation reaction under reduced pressure, or an organic It can be produced by a known solution heating dehydration condensation method using a solvent. From the viewpoint of economy and simplification of the production process, a melt polymerization method carried out in the absence of a solvent is preferred.

Moreover, the polycondensation reaction is preferably carried out in the presence of a polymerization catalyst. The timing of adding the polymerization catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be added at the time of charging the raw materials or at the start of depressurization.

Polymerization catalysts generally include compounds containing group 1 to group 14 metal elements in the periodic table, excluding hydrogen and carbon. Specifically, at least one metal selected from the group consisting of titanium, zirconium, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium, strontium, sodium and potassium and inorganic compounds such as oxides and halides of the metals mentioned above, and mixtures thereof.

Among these, metal compounds containing titanium, zirconium, germanium, zinc, aluminum, magnesium and calcium, and mixtures thereof are preferred, with titanium compounds and germanium compounds being particularly preferred.

In addition, the catalyst is preferably a compound that is in a liquid state during polymerization or dissolves in the ester low polymer or polyester because the polymerization rate increases if it is in a molten or dissolved state during polymerization.

The catalyst addition amount when using a metal compound as the polymerization catalyst is usually 5 ppm or more, preferably 10 ppm or more, as a metal amount with respect to the aromatic-aliphatic copolyester resin (a) to be produced. It is usually 30000 ppm or less, preferably 1000 ppm or less, more preferably 250 ppm or less, and particularly preferably 130 ppm or less. If the amount of catalyst used is too large, it is not only economically disadvantageous, but also the thermal stability of the resulting polymer is low. decomposition of is easily induced.

The reaction temperature for the esterification reaction and/or transesterification reaction between the dicarboxylic acid component and the diol component is generally 150° C. or higher, preferably 180° C. or higher, and generally 260° C. or lower, preferably 250° C. or lower. The reaction atmosphere is generally an inert gas atmosphere such as nitrogen or argon. The reaction pressure is usually normal pressure to 10 kPa, preferably normal pressure.
The reaction time is generally 1 to 10 hours, preferably 2 to 4 hours.

In the esterification reaction and/or the polycondensation reaction after the transesterification reaction between the dicarboxylic acid component and the diol component, the pressure is usually 0.01×10 ³ Pa or more, preferably 0.01×10 ³ Pa or more, It is usually carried out under a vacuum of 1.4×10 ³ Pa or less, preferably 0.4×10 ³ Pa or less. The reaction temperature at this time is generally 150° C. or higher, preferably 180° C. or higher, and generally 260° C. or lower, preferably 250° C. or lower. The reaction time has a lower limit of usually 2 hours or more and an upper limit of usually 15 hours or less, preferably 10 hours or less.

As a reactor for producing the aromatic-aliphatic copolyester resin (a) in the present invention, a known vertical or horizontal stirred tank reactor can be used. For example, using the same or different reactors, it is carried out in two stages, the step of esterification and / or transesterification of melt polymerization and the step of vacuum polycondensation, and the reactor for vacuum polycondensation is a vacuum pump and a reactor. A method of using a stirred tank reactor equipped with a connecting vacuum exhaust pipe may be used. In addition, a preferred method is a method in which a condenser is connected between the decompression exhaust pipe connecting the vacuum pump and the reactor, and volatile components generated during the polycondensation reaction and unreacted monomers are recovered in the condenser. be done.

In the present invention, the molar ratio of the diol component and the dicarboxylic acid component for obtaining the aromatic-aliphatic copolymerized polyester resin (a) with the desired degree of polymerization varies depending on the purpose and the type of raw material. However, the lower limit of the amount of the diol component relative to 1 mol of the dicarboxylic acid component is usually 0.8 mol or more, preferably 0.9 mol or more, and the upper limit is usually 1.5 mol or less, preferably 1.3 mol or less. Particularly preferably, it is 1.2 mol or less.

In addition, during the production process of the above-mentioned aromatic-aliphatic copolyester resin (a), or in the produced aromatic-aliphatic copolyester resin (a), the characteristics are not impaired. , various additives such as heat stabilizers, antioxidants, crystal nucleating agents, flame retardants, antistatic agents, release agents and UV absorbers may be added.

The aromatic-aliphatic copolymer polyester resin (a) used in the present invention preferably has an acid value of 10 equivalents/ton or more. More preferably, the aromatic-aliphatic copolyester resin (a) has an acid value of 13 equivalents/ton or more, more preferably 15 equivalents/ton or more. As this value increases, the interlayer adhesive strength between the biodegradable resin layer of the modified polyester resin (A) and the polyvinyl alcohol resin layer tends to increase when the adhesive resin composition is formed. Specific methods for controlling the acid value of the aromatic-aliphatic copolyester resin (a) include the following methods.
That is, when the melt polymerization reaction temperature is increased in the production of the aromatic-aliphatic copolyester resin (a) described above, the obtained aromatic-aliphatic copolyester resin (a) increases in acid value. Conversely, the acid value can be lowered by lowering the melt polymerization reaction temperature. The acid value of the obtained aromatic-aliphatic copolymer polyester resin (a) can also be controlled by adjusting the ratio of the diol component and the dicarboxylic acid component as raw materials to be used. That is, the acid value can be increased by increasing the ratio of the diol component to the dicarboxylic acid component, while the acid value can be decreased by decreasing the ratio of the diol component to the dicarboxylic acid component. can. Adjustment of the molar ratio between the diol component and the dicarboxylic acid component contributes to the control of the acid value, although it depends on the numerical value of the aromatic-aliphatic copolyester resin (a) with the desired degree of polymerization. The acid value can also be controlled by controlling the amount of catalyst used in the above polymerization reaction. Specifically, the acid value tends to increase as the amount of the catalyst increases, and conversely, the acid value tends to decrease as the amount of the catalyst decreases.

In addition, the terminal blocking agent used during production and the aromatic-aliphatic copolyester resin (a) may be stored after being mixed with the terminal blocking agent, but the aromatic-aliphatic When the group copolymerized polyester resin (a) contains a small amount of a terminal blocking agent, the acid value tends to decrease, and when it does not, the acid value tends to increase.

Examples of terminal blocking agents include, but are not limited to, carbodiimide compounds, epoxy compounds, isocyanate compounds, oxazoline compounds and the like, and isocyanate compounds are preferably used. These compounds may be used alone or in combination of two or more.
Examples of the isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2 ,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene Diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4- Cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate etc., and 1,6-hexamethylene diisocyanate is preferred.
The above isocyanate compound can be easily produced by a known method, and commercially available products can be used as appropriate.
When the end blocking agent is used, the amount is 0.05 to 15 mol%, preferably 0.1 to 12 mol%, relative to the aromatic-aliphatic copolyester resin (a). , more preferably 0.3 to 10 mol %. Whether or not the aromatic-aliphatic copolyester resin (a) contains a terminal blocking agent can be determined from the spectrum obtained by ¹ H-NMR measurement or IR measurement.

By combining these, the acid value of the aromatic-aliphatic copolyester resin (a) can be controlled.

Although the upper limit of the acid value of the aromatic-aliphatic copolymer polyester resin (a) is not particularly limited, it is usually 50 equivalents/ton or less from the viewpoint of water resistance and storage stability.

The method for measuring the acid value of the aromatic-aliphatic copolyester resin (a) is as described in Examples below.

In addition, the melt flow index (MFR) of the aromatic-aliphatic copolyester resin (a) used in the present invention is measured at 190 ° C. and 2.16 kg according to JISK7210 from the viewpoint of moldability, and the lower limit is It is usually 0.1 g/10 minutes or more, and the upper limit is usually 100 g/10 minutes or less, preferably 50 g/10 minutes or less, more preferably 30 g/10 minutes or less, and particularly preferably 10 g/10 minutes or less.

Such aromatic-aliphatic copolyester resin (a) may be used alone, two or more aromatic- The aliphatic copolyester resin (a) can also be blended and used.

From the viewpoint of biodegradability and flexibility, polybutylene terephthalate adipate is preferred as the aromatic-aliphatic copolymer polyester resin (a). Commercially available polybutylene adipate terephthalate can be used. For example, "Ecoflex" manufactured by BASF, "TUNHE TH801H" manufactured by Xinjiang Blue Ridge Tunhe Chemical Industry, etc. can be used.

<Modified polyester resin (A)>
In the present invention, the "modified polyester resin (A)" means a resin obtained by graft-modifying the above aromatic-aliphatic copolyester resin (a) with an unsaturated carboxylic acid and/or a derivative thereof. Here, "graft modification" means binding an unsaturated carboxylic acid and/or a derivative thereof to the aromatic-aliphatic copolyester resin (a). The bonding position of the unsaturated carboxylic acid and/or derivative thereof in the modified polyester-based resin (A) is not particularly limited as long as it is introduced into at least one of the main chain end and the side chain of the polyester-based resin.

The unsaturated carboxylic acid referred to herein is not particularly limited, but representative examples include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and the like. Derivatives of unsaturated carboxylic acids are not particularly limited, but typically include acid anhydrides, esters, amides, imides, metal salts and the like.

Specific examples of unsaturated carboxylic acid derivatives include maleic anhydride, hymic anhydride, itaconic anhydride, citraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, glycidyl acrylate, and maleic acid. monoethyl ester, maleic acid diethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N,N-diethylamide, maleic acid-N,N-monobutylamide, maleic acid-N,N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-monobutylamide, fumaric acid-N,N-dibutylamide, maleimide, N-butyl maleimide, N-phenyl maleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate and the like.

These unsaturated carboxylic acids and/or derivatives thereof may be used alone or in any combination and ratio of two or more.
Among these, maleic acid or its anhydride is particularly preferred because of its low electron density and high reactivity.

The ratio of the unsaturated carboxylic acid and/or its derivative to the aromatic-aliphatic copolyester resin (a) is not limited, but the aromatic-aliphatic copolyester resin (a) 100 parts by mass, the unsaturated It is desirable to add saturated carboxylic acid and/or its derivative in a proportion of usually 0.01 to 3 parts by mass, preferably 0.03 to 0.2 parts by mass. When the blending ratio of the unsaturated carboxylic acid and/or its derivative is equal to or less than the above upper limit, residual unreacted unsaturated carboxylic acid can be suppressed, and a multilayer molded article can be obtained without impairing the appearance. Moreover, if it is more than the said minimum, the adhesiveness of the adhesive resin composition obtained by ensuring the modification|denaturation amount can be improved.

Graft modification of the aromatic-aliphatic copolyester resin (a) can be carried out by conventionally known various methods. As a modification method, a melt modification method in which an unsaturated carboxylic acid and / or a derivative thereof is added to a molten aromatic-aliphatic copolymer polyester resin (a) for graft copolymerization, an aromatic dissolved in a solvent - A solution modification method in which an unsaturated carboxylic acid and/or a derivative thereof is added to the aliphatic copolyester resin (a) and graft copolymerization is performed, but the method is not particularly limited thereto. Among these, from the viewpoint of sanitation, the melt modification method that does not require the use of a solvent is preferred, and graft modification using an extruder is more preferred. For efficient graft modification, modification is preferably performed in the presence of a radical initiator.

Although the radical initiator is not particularly limited, an organic peroxide or an azo compound is preferable, and an organic peroxide is particularly preferable. Specifically, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl -2,5-di(t-butylperoxy)hexyne-3, 1,4-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl- 4,4-bis(t-butylperoxy)valerate, 2,2-bis(4,4-t-butylperoxycyclohexyl)propane, 2,2-bis(t-butylperoxy)butane, 1,1 -dialkyl peroxides such as bis(t-butylperoxy)cyclododecane; t-butyl peroxyacetate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl per Oxylaurate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, t-butyl peroxymaleic acid, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di( peroxy esters such as benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(toluylperoxy)hexane; Diacyl peroxides such as di-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, dibenzoyl peroxide; t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p- Hydroperoxides such as menthane hydroperoxide and 2,5-dimethyl-2,5-di(hydroperoxy)hexane; ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; It is not particularly limited. Radical initiators can be used singly or in any combination and ratio of two or more.

Among these, a radical initiator having a half-life of 1 minute and a decomposition temperature of 100° C. or higher is preferable from the viewpoint of graft modification efficiency. Specifically, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di( Dialkyl peroxides such as t-butylperoxy)hexyne-3, or t-butylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2 , 5-di(benzoylperoxy)hexyne-3 are preferred.

The amount of the radical initiator to be used is not particularly limited, but is preferably 0.001 to 1 part by mass with respect to 100 parts by mass of the aromatic-aliphatic copolymer polyester resin (a).

The modified polyester resin (A) used in the present invention has an acid value of 40 equivalents/ton or more, preferably 50 equivalents/ton or more, and more preferably 60 equivalents/ton or more. . The lower this value, the lower the adhesive strength. The acid value of the modified polyester resin (A) is correlated with the acid value of the aromatic-aliphatic copolymer polyester resin (a) and the acid value of the modified polyester resin (A). The acid value of the modified polyester resin (A) can also be controlled by controlling the acid value of the aromatic-aliphatic copolyester resin (a). The acid value of the modified polyester resin (A) can also be controlled by the amount of the unsaturated carboxylic acid and/or its derivative used for graft modification. If the aromatic-aliphatic copolyester resin (a) contains a terminal blocking agent, even if the aromatic-aliphatic copolyester resin (a) is graft-modified, the modified portion is the terminal Sealing with a sealing agent makes it difficult to develop adhesive strength, so it is preferable to use an aromatic-aliphatic copolyester resin (a) that does not contain a terminal blocking agent.

Although the upper limit of the acid value of the modified polyester resin (A) is not particularly limited, it is usually 200 equivalents/ton or less from the viewpoint of water resistance and storage stability.

The method for measuring the acid value of the modified polyester resin (A) is as described in Examples below.

The content of the unsaturated carboxylic acid and/or derivative thereof in the modified polyester resin (A) is not limited, but is usually 0.01% by mass or more, preferably 0.02% by mass or more, and more preferably 0.03% by mass or more. On the other hand, it is usually 3.0% by mass or less, preferably 1.0% by mass or less, more preferably 0.2% by mass or less. If the content of the unsaturated carboxylic acid and/or derivative thereof is at least the above lower limit, the adhesiveness of the adhesive resin composition of the present invention can be enhanced. It is possible to obtain a multi-layer molded article without impairing the appearance by suppressing the amount of acid, and to prevent problems such as deterioration of stability during hot-melt molding.
Here, the content of unsaturated carboxylic acid and/or its derivative in the modified polyester resin (A) can be determined from the spectrum obtained by ¹ H-NMR measurement or IR measurement.

The adhesive resin composition of the present invention may contain only one modified polyester resin (A), and is used for the composition, physical properties, and modification of the aromatic-aliphatic copolyester resin (a). It may contain two or more unsaturated carboxylic acids and/or derivatives thereof having different types and modified amounts.

<Other ingredients>
The adhesive resin composition of the present embodiment includes additives, other resins, etc. (hereinafter collectively referred to as " may be referred to as "other ingredients"). Other components can be used alone or in any combination and ratio of two or more.

Specific examples of additives include process oils, processing aids, plasticizers, crystal nucleating agents, impact modifiers, flame retardants, flame retardant aids, cross-linking agents, cross-linking aids, antistatic agents, lubricants, fillers, Examples include compatibilizers, heat stabilizers, weather stabilizers (antioxidants, light stabilizers, ultraviolet absorbers, etc.), carbon black, colorants (pigments, dyes, etc.), but are not particularly limited thereto. The content of these additives when used is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.2% by mass or more, relative to the total amount of the adhesive resin composition. , is preferably 5% by mass or less, more preferably 2% by mass or less.

Flame retardants are roughly classified into halogen flame retardants and non-halogen flame retardants. Among these, non-halogen flame retardants are preferred. Specific examples include metal hydroxides, phosphorus-based flame retardants, nitrogen-containing compound (melamine-based, guanidine-based) flame retardants, inorganic compound (borate, molybdenum compound) flame retardants, and the like.
Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, and alkali metal halides.
Fillers are roughly classified into organic fillers and inorganic fillers. Examples of organic fillers include naturally derived polymers such as starch, cellulose fine particles, wood flour, bean curd refuse, rice husks, bran, and modified products thereof. Inorganic fillers include talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon. Black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fibers, metal whiskers, ceramic whiskers, potassium titanate, boron nitride, graphite, carbon fibers and the like.

Specific examples of other resins used as other components include polyphenylene ether resins, polycarbonate resins, polyamide resins such as nylon 66 and nylon 11, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and styrene resins such as polystyrene. Examples thereof include resins and acrylic/methacrylic resins such as polymethyl methacrylate resins.
When the adhesive resin composition of the present invention contains these other resins, all resin components in the adhesive resin composition should be The ratio of other resins in the resin is preferably 50% by mass or less, particularly 30% by mass or less.

<Method for producing adhesive resin composition>
The adhesive resin composition of the present invention is obtained by mixing each of the above components by a conventionally known method, for example, a method of mixing with a Henschel mixer, a V-blender, a ribbon blender, a tumbler blender, or the like. After the mixture is further melt-kneaded with a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or the like, it can be obtained by granulating or pulverizing the obtained resin mass. Mixing can also be performed using a kneader or rolls. The production conditions for producing the adhesive resin composition by these methods are not particularly limited, and a conventional method may be used.

[Laminate]
Next, the laminated body of this invention is demonstrated.
The laminate of the present invention includes an adhesive layer made of the above-described adhesive resin composition of the present invention (hereinafter sometimes referred to as "adhesive resin composition layer of the present invention"). A preferred embodiment is a laminate having at least an adhesive layer and another layer, and having a laminated structure of two or three layers or more in which these layers are arranged so as to be in contact with each other.

In particular, the adhesive resin composition of the present invention includes a biodegradable resin layer such as an aliphatic polyester-based resin, an aliphatic oxycarboxylic acid-based resin, an aromatic-aliphatic copolyester-based resin, and a polyvinyl alcohol-based resin layer. Because it has excellent adhesion to both, the laminate of the present invention includes the adhesive resin composition layer of the present invention, an aliphatic polyester resin, an aliphatic oxycarboxylic acid resin, an aromatic-aliphatic copolymer A laminate having at least a biodegradable resin layer such as a polyester-based resin or a gas barrier layer such as a polyvinyl alcohol-based resin, and having a laminated structure of two or three or more layers arranged so as to be in contact with each other, especially fat Three-layer lamination of biodegradable resin layer such as tribal polyester resin, aliphatic oxycarboxylic acid resin, aromatic-aliphatic copolymer polyester resin / adhesive resin composition layer of the present invention / polyvinyl alcohol resin layer Laminates containing structural parts are preferred.

The shape of the laminate of the present invention is not particularly limited, and any form such as a laminated sheet, laminated film, laminated bottle, or the like can be employed.

As a method for producing the laminate of the present invention, various conventionally known methods can be employed. For example, a coextrusion method in which individual molten resins melted in an extruder are supplied to a multilayer die and laminated in the die to form an inflation film, T-die film, sheet, pipe, etc. Examples include co-injection molding, in which resins are injected into the same mold with a time lag, but are not limited to these. Moreover, it is also possible to obtain the laminate of the present invention by applying heat to laminate the resin films constituting each layer.

The laminate of the present invention using the adhesive resin composition of the present invention has the property of maintaining good adhesiveness and easy tearability even when stretched. Aspects can also be suitably used. As a method for obtaining a stretched laminate by stretching the laminate, conventionally known various methods can be employed, and the production method is not particularly limited. The stretching direction may be uniaxial stretching or biaxial stretching, and may be sequential stretching or simultaneous stretching.

For example, after cooling and solidifying the unstretched laminate obtained by the above method, it is reheated to a stretching temperature of 60 to 160° C. in-line or out-of-line, and is uniaxially or biaxially stretched using a tenter, plug, compressed air, or the like. A method of obtaining a stretched product such as a uniaxially or biaxially stretched film, cup, bottle, or the like by stretching in the direction at least 1.5 times or more in terms of area ratio. In the case of blown film, the simultaneous biaxial stretching method of inflation, the sequential biaxial stretching method with rolls and tenters, etc., in the case of cups, compressed air molding using only compressed air, etc., in the mold, and SPPF using both plugs and compressed air. Molding and the like are commonly used.

After obtaining a stretched laminate by stretching as described above, heat setting may be performed, or a product may be obtained without heat setting. That is, when heat setting is not performed, the stress is released when the film is subsequently heated, and the film can be used as a shrink film that thermally shrinks.

The thickness of each layer of the laminate or stretched laminate of the present invention can be arbitrarily set according to the required performance, such as the layer structure, application, shape of the final product, required physical properties, etc., and is not particularly limited. For example, when used as a film for food packaging or industrial product packaging, the total thickness of the unstretched laminate is preferably 30-400 μm, more preferably 40-300 μm, and still more preferably 50-200 μm. The thickness of the adhesive resin composition layer of the present invention that constitutes the non-stretching laminate is preferably 1 to 100 μm, more preferably 2 to 80 μm, and still more preferably 3 to 50 μm. Further, the total thickness of the stretched laminate (stretched film) when used for this purpose is preferably 5 to 400 μm, more preferably 10 to 300 μm, still more preferably 20 to 200 μm. At this time, the thickness of the adhesive resin composition layer of the present invention constituting the stretched film is preferably 0.1 to 50 μm, more preferably 0.3 to 30 μm, still more preferably 0.5 to 20 μm.

On the other hand, when used as a thick molded product such as a bottle for food, sanitary products, or general industrial products, the total thickness of the non-stretched or stretched laminate is preferably 0.1 to 7 mm, more preferably 0.1 to 7 mm. 0.15 to 6 mm, more preferably 0.2 to 5 mm. The thickness of the adhesive resin composition layer of the present invention at this time is preferably 3 to 300 μm, more preferably 4 to 200 μm, still more preferably 5 to 100 μm.

When the laminate of the present invention is applied to food packaging materials, etc., depending on the application, it is formed into a product shape such as a cup or tray by solid-phase pressure molding (sometimes referred to as "SPPF molding") or vacuum molding. Even in that case, according to the adhesive resin composition of the present invention, high interlayer adhesion can be maintained even if secondary processing involving a stretching process such as SPPF molding or vacuum molding is performed. .

As a method for producing a multilayer container or the like from the multilayer film or multilayer sheet that is the laminate of the present invention (hereinafter sometimes referred to as "secondary processing"), various conventionally known methods can be employed. can. For example, a multilayer film or a multilayer sheet, which is a laminate produced by the above primary processing, is heated and molded in a mold using only compressed air, etc., and a multilayer film or multilayer sheet, which is a laminate produced by the above primary processing. is heated and softened to adhere to the mold, air is discharged from the exhaust port provided in the mold, the molded body is adhered to the mold, and then cooled to perform secondary processing. There are vacuum pressure molding in which one surface and the opposite surface are formed by compressed air, container molding such as cups by SPPF molding using both a plug and compressed air, and container molding such as cups and bottles in which a co-injection molded product is further stretch-molded.

Among these secondary processes, vacuum forming is not particularly limited, but the surface temperature of the molded body is usually in the range of 120 to 250 ° C., preferably in the temperature range of 120 to 220 ° C., more preferably in the range of 120 to 200 ° C. °C temperature range. When the surface temperature is within the above range, the drawdown property and shapeability are improved, and the thickness becomes uniform.

In addition, the molding of a container such as a cup by SPPF molding is not particularly limited, but the molding temperature is in the range of 300 to 380°C, further 310 to 370°C, particularly 320 to 360°C. It is preferable that the surface temperature of the molded product is in the range of 130 to 180°C, more preferably in the range of 140 to 170°C, particularly in the range of 150 to 160°C.
In SPPF molding, when the temperature is below the melting peak temperature of the resin constituting the main layer of the multi-layer sheet, the laminate is preferably heated at a temperature such that the difference from the melting peak temperature is in the range of 5 to 30°C. Then, the multilayer sheet is preformed into a container shape by depressing the assist plug, and then air pressure is applied to the preformed portion to form the multilayer sheet. A thermoformed article can be molded by bringing it into close contact with the mold cavity surface. The container obtained by the molding has excellent rigidity and impact strength.

[Use]
The adhesive resin composition of the present invention is compatible with both biodegradable resins such as aliphatic polyester resins, aliphatic oxycarboxylic acid resins, aromatic-aliphatic copolymer polyester resins, and polyvinyl alcohol resins. It exhibits excellent adhesive strength characteristics against other materials, and maintains high interlaminar adhesive strength even after secondary processing. Therefore, the laminate of the present invention using such an adhesive resin composition of the present invention as an adhesive layer exhibits excellent adhesive strength characteristics, and is also excellent in strength, heat resistance, gas barrier properties, and the like. In addition, its biodegradability can reduce the environmental load. Therefore, the laminate of the present invention and a molded article such as a multilayer container manufactured from this laminate can be used as packaging materials for edible oil bottles, livestock meat packaging films such as ham, general food packaging materials such as jelly cups and cooked rice trays, and design packaging. and labels.
Especially preferred is the use for general food packaging materials such as jelly cups and cooked rice trays produced by SPPF molding that involves secondary processing at low temperatures.

Specific embodiments of the present invention will be described in more detail below using examples, but the present invention is not limited by the following examples as long as the gist thereof is not exceeded. Various production conditions and values of evaluation results in the following examples have the meaning of preferred values of the upper limit or the lower limit in the embodiments of the present invention, and the preferred range is the above-described upper limit or lower limit value. , the range defined by the values in the following examples or a combination of the values in the examples.

[Evaluation of physical properties]
Polybutylene adipate terephthalate used in the following examples and comparative examples and the acid value of the modified polyester resin produced, the measurement of the MFR of the polybutylene adipate terephthalate, and the end capping of the aromatic-aliphatic copolymer polyester resin The presence or absence of inhibitors was confirmed by the following method.

<Measurement of acid value>
After pulverizing the sample, it is dried at 140° C. for 15 minutes in a hot air dryer, cooled to room temperature in a desiccator, and 0.1 g of the sample is precisely weighed and collected in a test tube, and 3 ml of benzyl alcohol is added. The solution was dissolved at 195° C. for 3 minutes while blowing dry nitrogen gas, then 5 ml of chloroform was gradually added and cooled to room temperature. 1 to 2 drops of phenol red indicator was added to the solution, and titration was carried out with 0.1N sodium hydroxide in benzyl alcohol while stirring while blowing dry nitrogen gas. As a blank, the same operation was performed without dissolving the polyester resin sample, and the acid value, which is the amount of terminal carboxyl groups, was calculated by the following formula (1).

Acid value (equivalent/ton) = (ab) x 0.1 x f/w (1)
(where a is the amount (μl) of 0.1N sodium hydroxide benzyl alcohol solution required for titration, and b is the amount of 0.1N sodium hydroxide benzyl alcohol solution required for blank titration. Amount (μl), w is the amount of polyester resin sample (g), f is the titer of 0.1 N sodium hydroxide solution in benzyl alcohol.)

The titer (f) of a 0.1N sodium hydroxide solution in benzyl alcohol was obtained by the following method.
Take 5 ml of methanol in a test tube and add 1 to 2 drops of phenol red in ethanol as an indicator. Titrate to the color change point with 0.4 ml of 1N sodium hydroxide benzyl alcohol solution, then add 0.2 ml of 0.1N hydrochloric acid aqueous solution with known titer as a standard solution, and again add 0.1N hydroxylation. A solution of sodium in benzyl alcohol was titrated to the color change point (the above operation was performed while blowing dry nitrogen gas). The titer (f) was calculated by the following formula (2).
Potency (f) = Potency of 0.1N hydrochloric acid aqueous solution × Collected amount of 0.1N hydrochloric acid aqueous solution (µl)/Titration volume of benzyl alcohol solution of 0.1N sodium hydroxide (µl) 2)

<Measurement of MFR>
It was measured under conditions of 190° C. and a load of 2.16 kg according to JISK7210.

<Confirmation of presence or absence of end blocking agent contained in aromatic-aliphatic copolymer polyester resin>
About 20 mg of sample was dissolved in 0.7 mL of CDCl ₃ (containing 0.03 v/v % TMS) in an NMR sample tube with an outer diameter of 5 mm. ¹ H using a Bruker AVANCE 400 spectrometer
NMR spectra were measured. The presence or absence of a peak of hexamethylene diisocyanate contained as a terminal blocker was confirmed.

[Example 1]
<Production of modified polyester resin (A-1)>
As the aromatic-aliphatic copolyester resin (a-1), 100 parts by mass of polybutylene adipate terephthalate (Xinjiang Blue Ridge Tunhe Chemical Industry Co., Ltd. "TUNHE TH801H)" was used, and 0.1 part by mass of maleic anhydride was added thereto. , 0.014 parts by mass of 2,5-dimethyl-2,5-bis(t-butyloxy)hexane (“Perhexa 25B” manufactured by NOF Co., Ltd.) as a radical initiator was blended by dry blending, and a twin-screw extruder was used. Using TEX25αIII-52.5CW-3V (D=25 mmφ, L/D=53, manufactured by The Japan Steel Works, Ltd.), the mixture was melt-kneaded at a temperature of 220° C., a screw rotation speed of 200 rpm, and an extrusion rate of 20 kg/h. Thereafter, the melt-kneaded product was extruded in a string shape, cooled and then cut to obtain pellets of the modified polyester resin (A-1).
The modified polybutylene adipate terephthalate had an acid value of 17 equivalents/ton and an MFR of 3.1 g/10 minutes, and the resulting modified polyester resin (A-1) had an acid value of 70 equivalents/ton. there were.

<Preparation of multilayer film>
Using the pellets of the modified polyester resin (A-1) as an adhesive resin composition for the adhesive layer, a multilayer film (laminate ) was made.
Polylactic acid layer/adhesion using polylactic acid (“Ingeo4032D” manufactured by Nature Works), modified polyester resin (A-1), polyvinyl alcohol resin (“G-Polymer OKS-8049P” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) A laminate having a 3-kind 5-layer structure of layer/polyvinyl alcohol-based resin layer/adhesive layer/polylactic acid layer was produced. The total thickness of the obtained laminate was 250 µm, and the thickness of each layer was 90 µm/20 µm/30 µm/20 µm/90 µm, respectively. The molding temperature was set at 210° C. and the molding speed was set at 10 m/min.

<Measurement of adhesive strength>
A strip having a width of 15 mm was cut from the laminate obtained above to obtain a test piece, and a T-peel peeling test was performed in an atmosphere of 23° C. at a rate of 100 mm/min. Table 1 shows the results.

[Comparative Example 1]
Polybutylene adipate terephthalate ("Ecoflex C1200" manufactured by BASF) having an acid value of 9 equivalents/ton and an MFR of 3.1 g/10 minutes was used as the aromatic-aliphatic copolyester resin (a-2), and this polybutylene 100 parts by mass of adipate terephthalate, 0.05 parts by mass of maleic anhydride, and 0.014 parts of 2,5-dimethyl-2,5-bis(t-butyloxy)hexane ("Perhexa 25B" manufactured by NOF Co., Ltd.) as a radical initiator. A mixture obtained by dry-blending parts by mass was extruded using a twin-screw extruder TEX25αIII-52.5CW-3V (D = 25 mmφ, L / D = 53, manufactured by Japan Steel Works, Ltd.) at a temperature of 220 ° C. and a screw. Melt-kneading was performed at a rotational speed of 200 rpm and an extrusion rate of 20 kg/h. After that, the molten kneaded mixture was extruded into a string, cooled and then cut to obtain pellets of the modified polyester resin (A-2). The acid value of this modified polyester resin (A-2) was 23 equivalents/ton.
A laminate was produced in the same manner as in Example 1, except that this modified polyester resin (A-2) was used as the adhesive resin composition of the adhesive layer, and the adhesive strength was measured in the same manner.
Table 1 shows the results.

From Table 1, according to the modified polyester resin (A-1) with an acid value of 40 equivalents/ton or more, compared to the case of using the modified polyester resin (A-2) with an acid value of less than 40 equivalents/ton It can be seen that remarkably excellent adhesive strength can be obtained between the biodegradable resin layer and the polyvinyl alcohol-based resin layer.

The adhesive resin composition of the present invention is excellent for both biodegradable resins such as aliphatic polyester resins, aliphatic oxycarboxylic acid resins, aromatic-aliphatic copolyester resins, and polyvinyl alcohol resins. It shows the adhesive strength characteristics. In addition, the laminate of the present invention exhibits excellent adhesive strength properties, is excellent in strength and gas barrier properties, and can be made so that all components of the laminate are biodegradable. Therefore, the laminate of the present invention and the molded article obtained by secondary processing thereof can be used as packaging materials for general foods such as edible oil bottles, meat packaging films such as ham and sausages, coffee capsule containers, etc., and pharmaceuticals. , quasi-drugs, cosmetics, medical equipment, regenerative medicine products, and other medical or cosmetic packaging materials, outer packaging materials, labels, etc., can be widely and effectively used.

Claims (7)

A modified polyester obtained by graft-modifying an aromatic-aliphatic copolymer polyester resin (a) containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit with an unsaturated carboxylic acid and/or a derivative thereof An adhesive resin composition containing a resin (A),
The amount of aromatic dicarboxylic acid units in the aromatic-aliphatic copolymer polyester resin (a) is 50 mol% or less with respect to the total of the aliphatic dicarboxylic acid units and the aromatic dicarboxylic acid units,
An adhesive resin composition, wherein the modified polyester resin (A) has an acid value of 40 equivalents/ton or more. The adhesive resin composition according to claim 1, wherein the aromatic-aliphatic copolyester resin (a) is biodegradable. 3. The adhesive resin composition according to claim 1, wherein the aromatic-aliphatic copolyester resin (a) is polybutylene adipate terephthalate. The amount of the unsaturated carboxylic acid and/or derivative thereof as a modifier is 0.01 parts by mass to 3 parts by mass with respect to 100 parts by mass of the aromatic-aliphatic copolymer polyester resin (a). , The adhesive resin composition according to any one of claims 1 to 3. A laminate comprising an adhesive layer comprising the adhesive resin composition according to any one of claims 1 to 4. A solid-phase pressure-molded article comprising an adhesive layer comprising the adhesive resin composition according to any one of claims 1 to 4. A food packaging material comprising the molded article according to claim 6 .