JP2544754B2 - Laminated structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is a substrate selected from polycarbonate, polyacrylic resin and polyamide, and in particular, at least one surface of a polycarbonate substrate has a Tg (glass transition point) of 50 ° C. or less. Of the polyester amide and a saponified product of ethylene-vinyl acetate copolymer (hereinafter referred to as EVOH).

B. Conventional Technology Polycarbonate has a wide range of uses as a resin having extremely excellent transparency among general-purpose resins. However, not all properties can be satisfied by polycarbonate alone. For example, when used in hollow containers for foods and non-foods, high gas barrier properties are required in fields where it is necessary to prevent oxidation of contents or retain scent. As a method of imparting gas barrier properties, a method in which a multilayer structure (film, sheet, parison, etc.) in which EVOH and polycarbonate are laminated is secondarily processed into a container or the like can be considered.

On the other hand, it is possible to form a coating with a relatively thin film thickness, to easily form a coating on a substrate having a complicated shape such as a hollow container, and to perform a coating operation with a relatively simple device.
A solution coating method of applying a solution dissolved in an EVOH solvent to a substrate is currently drawing attention. Further, in the coating method, since EVOH is a resin having oil resistance, it is possible to impart oil resistance to the polycarbonate by forming an EVOH layer on the polycarbonate surface.

When the polycarbonate layer and the EVOH layer are laminated by using the solution coating method, the two do not adhere at all unless an adhesive layer is provided in the intermediate layer. As the adhesive used for such an application, a polyurethane-based adhesive is mainly used, but usually, the adhesive solution is applied and dried on a polycarbonate as a base material, and then an EVOH solution is applied and dried to obtain an EVOH. And a laminated structure of polycarbonate is obtained. However, the process of applying and drying the adhesive solution and the EVOH solution respectively requires complicated equipment and is disadvantageous in terms of cost.

Therefore, if a solution obtained by mixing an adhesive with an EVOH solution is used, it is very useful in terms of cost by simplifying the coating and drying process of the adhesive and omitting the solvent of the adhesive solution. As a method thereof, Japanese Patent Publication No. 30600/1985 proposes blending polyethyleneimine with an EVOH solution. However, this method strongly adheres to the polyolefin-based polymer but hardly adheres to the polycarbonate.

In addition, USP4459400 (JP-A-60-144330) and U.S.P.
SP4481238 (Tokuyo Sho-60-501312) describes the use of polyesteramide as an interlayer adhesive between EVOH layer and PET layer, but polyesteramide is superior to polycarbonate or polyacrylic resins and polyamide. It does not disclose that it has adhesiveness, and further that it laminates a mixture layer of EVOH and polyesteramide and the above-mentioned resin such as polycarbonate, and that by doing so, a laminated structure having excellent adhesiveness can be obtained.

C. Problems to be Solved by the Invention The present invention is to provide a laminated structure in which EVOH is firmly adhered to a resin such as the above-described polycarbonate while simplifying the step of applying and drying the adhesive.

D. Means for Solving the Problems According to the present invention, the above object is to provide a polyester amide having a Tg (glass transition point) of 50 ° C. or less and an ethylene-vinyl acetate copolymer on at least one surface of the above-mentioned resin base material such as polycarbonate. This is achieved by providing a laminated structure having a mixture layer in which the weight ratio of the polymer saponified product is 5:95 to 35:65.

E. More Detailed Description of the Invention The most important feature of the present invention is that the mixture of polyesteramide and EVOH strongly adheres to the polycarbonate substrate.

The polyesteramide referred to in the present invention needs to have a Tg (glass transition point) of 50 ° C. or lower, preferably 40 ° C. or lower, particularly preferably 30 ° C. or lower. When Tg exceeds 50 ° C., not only the compatibility with EVOH decreases but also the adhesive strength between the polycarbonate substrate and EVOH decreases.

Polyesteramide is a polymer composed of a reaction product of a diamine component, a diol component and a dicarboxylic acid component and having an ester repeating unit and an amide repeating unit in one polymer chain. The diamine component consists of at least one diamine having about 2 to 14 carbon atoms and is preferably aliphatic, but aromatic diamines may be added within the range not departing from the spirit of the present invention. Suitable diamines include hexamethylene diamine, piperazine,
1-aminoethylpiperazine, bisaminopropylpiperazine, 1,3-dipiperidylpropane, 1,4-cyclohexanebismethylamine, 1,2-ethanediamine, or a mixture thereof or the like is included. The diol component is about 2
It consists of at least one diol containing up to 14 carbon atoms. Suitable diols include ethylene glycol, 1,4
-Butanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol,
Or a mixture thereof and the like are included.

The polyesteramide further comprises a dicarboxylic acid component. The dicarboxylic acid component consists of at least one dicarboxylic acid containing up to about 5 to 14 carbon atoms and is preferably aliphatic, but addition of an aromatic dicarboxylic acid within the scope of the present invention is not critical. Is also good. Suitable dicarboxylic acids are sebacic acid, azelaic acid, adipic acid,
A mixture thereof and the like are included.

The polyesteramide referred to in the present invention is synthesized by a method generally known in the art for producing a polyesteramide. Usually, it is produced by a melt phase polymerization method from a diamine component, a diol component and a dicarboxylic acid component in the presence of a catalyst (preferably a titanium compound). Examples include JP-A-60-144330, JP-A-61-501312, and the like. The polyesteramide used in the present invention is an ester component and an amide component in the polymer chain of 5:95 ~.
The resin is contained in a molar ratio range of 40:60, preferably 10:90 to 30:70. If the amount of the ester component is 5 mol% or less, the adhesive strength with the polycarbonate is lowered, while if it is 40 mol% or more, the compatibility with EVOH is lowered.

EVOH used in the present invention has an ethylene content of 20 to 60 mol%,
Preferably 25 to 55 mol%, the degree of saponification of the vinyl acetate component is 90
% Or more, preferably 95% or more. 20 ethylene content
When it is at most mol%, the gas barrier property at high humidity will be lowered, or the water resistance will be lowered. On the other hand, if it is 60 mol% or more, sufficient gas barrier properties cannot be obtained. . Further, when the saponification degree is 90% or less, the gas barrier property and the moisture resistance decrease.

EVOH is also a small amount of propylene, isobutene, α
An α-olefin such as octene, an unsaturated carboxylic acid or a salt thereof, a partial alkyl ester thereof, a complete alkyl ester thereof, a nitrile thereof, an amide thereof, an anhydride thereof,
It may contain a comonomer unit such as an unsaturated sulfonic acid or a salt thereof.

Regarding the blending ratio of polyesteramide and EVOH, if the blending ratio of polyesteramide is low, the adhesiveness with polycarbonate is poor and a satisfactory composite structure cannot be obtained.
On the other hand, if the blending ratio of the polyesteramide is too large, the gas barrier property is deteriorated. Therefore, the blending ratio of the polyesteramide is in the range of 5 to 35% by weight, preferably 10 to 30% by weight, based on the total weight of the polyesteramide and EVOH.

As a method of providing a mixture layer of polyesteramide and EVOH on at least one surface of a polycarbonate substrate, polyesteramide and EVOH are dissolved in these common solvents,
The method of applying this is the most effective. The common solvent here is methyl alcohol, ethyl alcohol,
Monohydric alcohols such as propyl alcohol and butyl alcohol, dihydric alcohols such as ethylene glycol and propylene glycol, trihydric alcohols such as glycerin, phenols such as phenol and cresol, amines such as ethylenediamine and trimethylenediamine, and formic acid. Acids, dimethylsulfoxide, dimethylacetamide, N-methylpyrrolidone, and the like, and hydrates thereof are used alone or in combination of two or more. Particularly preferably used solvents are water-alcohol-based mixed solvents such as water-normal propyl alcohol, water-isopropyl alcohol and water-methyl alcohol.

The concentration of the mixed solution of polyesteramide and EVOH can be applied at any concentration, but normally, it is preferably about 2 to 20% by weight.

As a method for applying a solution of a mixture of polyesteramide and EVOH, any known method such as a roller coating method, a spray coating method, a dip coating method, or the like can be applied. The coating surface of the polycarbonate substrate is 1
It may be a surface, two surfaces, or the entire surface.

After applying a mixed solution of polyesteramide and EVOH to a polycarbonate substrate, drying is performed. The drying temperature is
30 ~ 200 ℃, preferably 10 ~ 10 seconds at a temperature of about 50 ~ 150 ℃
It may be heated for about a minute. The coating can be dried until the volatile content is almost eliminated, but the volatile content in the coating can be prevented in order to prevent cracking of the coating and to maintain the transparency of the coating and the adhesive strength of the layer for a long period of time. It is advantageous to leave 0.5 to 5% by weight.

In the present invention, a mixture of EVOH and polyesteramide may be appropriately blended with additives such as a weather resistance stabilizer, an antioxidant, a filler, a reinforcing agent (such as glass fiber), a colorant, a surfactant, and a soluble inorganic salt. You can

In the present invention, the film thickness (thickness after evaporation of the solvent) of the mixture layer of polyesteramide and EVOH applied to the polycarbonate substrate is practically about 0.5 to 20 μm.
If it is 0.5 μm or less, sufficient gas barrier properties are obtained. On the other hand, if it is 20 μm or more, operations such as increasing the number of coatings are required in order to obtain a film having a target film thickness, which causes a problem that productivity is remarkably reduced.

The formation of the composite structure is not limited to solution coating and can be performed by a method called hot pressing or coextrusion. For example, the composite structure can be formed by pressing a melt-blended film of EVOH and polyesteramide and a polycarbonate film under heating, or by coextruding a mixture of EVOH and polyesteramide and polycarbonate.

In the present invention, the polycarbonate is a diol component linearly bonded in the molecule through a carbonic acid ester bond. As the diol component, 4,4'-dihydroxydiphenyl-1,1-ethane, 4,4'-dihydroxydiphenyl-2,2-propane, 4,4'-dihydroxydiphenylsulfone and the like are used. These are methods of transesterifying a carbonic acid ester such as diphenyl carbonate with or without a catalyst, and then placing it under reduced pressure.
Alternatively, it can be obtained by a known method such as a method of reacting with phosgene in the presence of an acid binder. The polycarbonate substrate may be any film, sheet, hollow bottle, tube or the like.

Applications of the laminate of the present invention include packaging materials for foods, beverages, medicines, medical products, containers and the like. It is also possible to coat or laminate a mixture of EVOH and polyester amide on a polycarbonate substrate, and then draw and / or heat-treat to obtain a desired molded product.

Further, if necessary, a moisture-proof layer can be formed on the EVOH-polyesteramide layer of the composite structure by vinylidene chloride resin coating, vinyl chloride-vinyl acetate copolymer coating, or the like. In addition to the composite structure, the composite material laminated on polyester, polyolefin or the like can be used as a packaging material for foods, beverages, medicines, medical treatments, containers or the like.

In the present invention, even when a mixture of EVOH and polyesteramide is laminated on a polyacrylic resin or a polyamide resin other than polycarbonate, a laminated structure in which both are firmly adhered can be obtained.

Polyacrylic resins and polyamide resins have excellent moldability, but their gas barrier properties are not sufficient. Furthermore, the oil resistance of polyacrylic resins is not sufficient. Therefore, by laminating a mixture of EVOH and polyester amide on a polyacrylic resin or a polyamide resin, these properties are improved and it becomes useful for food packaging materials (materials such as containers, cups and films).

The method of laminating the mixture of EVOH and polyesteramide on these resin substrates is the same as the method of laminating on the above-mentioned polycarbonate substrate. In order to improve the adhesive strength, the base material may be subjected to surface treatment such as corona discharge treatment or fire treatment in advance.

Examples of the polyacrylic resin include polyacrylic acid esters (eg, polymethyl acrylate, polyethyl acrylate), polymethacrylic acid esters (eg, polymethyl methacrylate), polyacrylonitonil, and the like. Polymethylmethacrylate is preferably used.

Examples of polyamides include 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon and derivatives thereof.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. All percentages and parts are by weight unless otherwise specified. Also, Tg (glass transition point)
Was measured using a Perkin-Elmer DSC-2 differential scanning calorimeter.

F. Examples Examples 1 to 4 Polyesteramide (Tg: 20.5) composed of azelaic acid / cyclohexanedimethanol / piperazine = 0.50 / 0.09 / 0.41 (molar ratio; ester component: amide component = 18: 82)
℃) and ethylene content 32 mol%, saponification degree 99.5% EVOH in a weight ratio of 5:95, 10:90, 15:85, 20:80 10 parts of a mixture of 35% water, 65% n-propyl alcohol Mixed solvent containing 90
And added to each part and stirred at 70 to 80 ° C. for about 2 hours to obtain 4 kinds of transparent solutions. After cooling these solutions to a liquid temperature of 25 ° C, a polycarbonate film 100μ (Iupilon film: manufactured by Mitsubishi Gas Chemical Industry Co., Ltd.) was coated with the above solution by an applicator coating method and dried at 70 ° C for 10 minutes to volatilize. A coating film of EVOH (film thickness 5 μ) having a content of about 3% was formed.

 Various performances of the composite structure are shown in Table 1.

Example 5 Azelaic acid / ethylene glycol / piperazine = 0.
50 / 0.13 / 0.37 (molar ratio; ester component: amide component = 2
6:74) polyester amide (Tg: -2.3 ° C) and EVOH with an ethylene content of 32 mol% and a saponification degree of 99.5%
10 parts of a mixture of 5:85 was added to 90 parts of a mixed solvent containing 30% of water and 70% of n-propyl alcohol, and stirred at 70 to 80 ° C for about 2 hours to obtain a transparent solution. Liquid temperature of this solution
After cooling to 25 ℃, polycarbonate film 100μ
(Eupiron film: manufactured by Mitsubishi Gas Chemical Industry Co., Ltd.) is coated with the above solution by an applicator coating method and dried at 80 ° C. for 5 minutes to form a coating film of EVOH (film thickness 2 μ) having a volatile content of 1.5%. It was

When the transparency of the composite structure was measured, the Haze degree was 2.6.
%, Indicating good transparency.

The oxygen permeability of the composite structure was measured under the condition of 20 ° C-65% RH, and it was 9.3cc / m ² · day · atm (EV
OH layer only).

In addition, the composite structure polycarbonate film and EV
When the 180 degree peel strength between the OH coated films was measured, it was 950 g /
It was 15 mm wide.

Example 6 Sebacic acid / neopentyl glycol / piperazine =
0.50 / 0.05 / 0.45 (molar ratio; ester component: amide component =
10:90) polyester amide (Tg: 23.3 ° C) and EVOH with an ethylene content of 44 mol% and a saponification degree of 99.6% have a weight ratio of 1
10 parts of the mixture of 0:90 were added to 90 parts of a mixed solution containing 30% of water and 70% of n-propyl alcohol, respectively, and stirred at 70 to 80 ° C. for about 2 hours to obtain a transparent solution. Liquid temperature of this solution
After cooling to 25 ℃, polycarbonate film 100μ
(Eupiron film: manufactured by Mitsubishi Gas Chemical Industry Co., Ltd.) is coated with the solution by an applicator coating method and dried at 80 ° C. for 5 minutes to form a coating film of EVOH (thickness 2 μm) having a volatile content of 1.2%. It was

When the transparency of the composite structure was measured, the Haze degree was 1.8.
%, Indicating good transparency.

Further, when the oxygen permeability of the composite structure was measured under the condition of 20 ° C.-65% RH, it was 18.2 cc / m ² · day · atm (E
VOH layer only).

In addition, the composite structure polycarbonate film and EV
When the 180 degree peel strength between the OH coated films was measured, it was 180 g /
It was 15 mm wide.

Comparative Examples 1 to 2 Various performances of the composite structure in which the mixing ratio of polyesteramide and EVOH is 2:98, 40:60 are shown by the same coating film forming method as shown in Examples 1 to 4. Shown in 1.

In Comparative Example 1, the Haze degree indicating transparency and the oxygen permeability indicating gas barrier property were comparable to those in Examples 1 to 4, but the 180 degree peel strength indicating adhesive strength was very small, which was a problem in practical use. there were.

In Comparative Example 2, there was no problem in the adhesive strength and transparency, but the gas barrier property was extremely lowered.

Example 7 Polyesteramide (Tg: 20.5) consisting of azelaic acid / cyclohexanedimethanol / piperazine = 0.50 / 0.09 / 0.41 (molar ratio; ester component; amide component = 18: 82)
℃), ethylene content 32 mol%, saponification degree 99.5% EVOH 10: 90 weight ratio of the mixture of 10 parts to 90 parts of a mixed solvent containing 35% water and 65% n-propyl alcohol, respectively. In addition, the mixture was stirred at 70 to 80 ° C for about 2 hours to obtain two types of transparent solutions. After cooling these solutions to a liquid temperature of 25 ° C, the solution is applied to a polymethylmethacrylate (PMMA) sheet 1000μ (Clarex sheet: Nitto Jushi Kogyo Co., Ltd.) by the applicator coating method, and the solution is applied at 80 ° C After drying for 1 minute, a coating film of EVOH (film thickness 5 μm) having a volatile content of about 2.5% was formed.

Table 2 shows the 180-degree peel strength between the PMMA sheet and the EVOH coated film of the composite structure.

Example 8 Two types of EVOH solutions were obtained in the same manner as in Example 7. Corona discharge treatment of these solutions in advance (corona discharge output: 1 kw, treatment speed: 20 m / min.) 6-nylon film 15μ (emblem: Unitika) was coated with the above solution by an applicator coating method, and the temperature was raised to 80 ° C. The coating was dried for 10 minutes to form a coating film of EVOH (film thickness 5 μm) having a volatile content of about 2.5%.

Table 2 shows the 180-degree peel strength between the 6-nylon film and the EVOH-coated film of the composite structure.

G. Effect of the Invention According to the present invention, it is possible to obtain a laminated structure in which EVOH is firmly adhered to a substrate such as polycarbonate, polyacrylic resin, or polyamide, which has excellent gas barrier properties and oil resistance.

Claims (6)

(57) [Claims] 1. Tg on at least one surface of a substrate selected from polycarbonate, polyacrylic resin and polyamide.
The weight ratio of polyesteramide (glass transition point) below 50 ℃ and saponified ethylene-vinyl acetate copolymer is 5:95 to 3
Laminated structure having a mixture layer of 5:65. 2. A polyesteramide having at least one repeating unit of a diamine component having 2 to 14 carbon atoms, at least one repeating unit of a diol component having 2 to 14 carbon atoms, and a dicarboxylic acid component having 5 to 14 carbon atoms. The laminated structure according to claim 1, which comprises at least one repeating unit of, and contains the ester component and the amide component in the polyester amide at a molar ratio of 5:95 to 40:60. 3. A saponification product of an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, and a saponification degree of a vinyl acetate component of 90.
The laminated structure according to claim 1, which has a content of at least%. 4. The laminated structure according to claim 1, wherein the film thickness of the mixture layer of the polyesteramide and the saponified product of the ethylene-vinyl acetate copolymer is 0.5 to 20 μm. 5. The laminated structure according to claim 1, wherein the surface of a base material selected from polycarbonate, polyacrylic resin and polyamide is previously subjected to corona discharge treatment or flame treatment. 6. A mixture layer of polyesteramide and a saponified product of ethylene-vinyl acetate copolymer, which is obtained by coating a mixed solution of a polyesteramide and a saponified product of ethylene-vinyl acetate copolymer and drying. The laminated structure according to item 1.