JP2019111794A - Coating plastic molded body and manufacturing method therefor - Google Patents

Abstract

To provide a coating plastic molded body improved gas barrier property compared to conventional ones, and a manufacturing method therefor.SOLUTION: The coating plastic molded body 90 has a plastic molded body 91, a gas barrier thin film 93 coating a surface of the plastic molded body 91, and a curing layer 92 coating a surface of the gas barrier thin film 93 and consisting of a condensation polymer of a compound represented by the general formula (Chemical 1). (Chemical 1) R-M-(CH)(OR'). In the general formula (Chemical 1), M represents silicon or a metal, R represents a hydrocarbon chain having an amino group, R' represents an alkyl group having 1 to 4 carbon atoms, and n represents 0, 1 or 2.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to coated plastic moldings that can be combined with gas barrier films and methods of making the same.

  Plastics is excellent in transparency, lightness, impact resistance, corrosion resistance, processing and moldability, and has the advantages of being inexpensive and being able to cope with high-mix low-volume production, so packaging food, beverages, medicines, cosmetics, etc. Suitable as packaging material. However, plastic has lower gas barrier properties compared to other packaging materials, such as metal or glass, and has a problem that it is not suitable as a packaging material for contents that are resistant to oxidation or contents containing gas such as beer. .

  Therefore, a coated plastic molded body provided with a thin film having gas barrier properties (hereinafter also referred to as a gas barrier thin film) has been proposed. For example, a gas barrier film having excellent gas barrier properties is obtained by forming a coating film comprising non-water-soluble resin fine particles and one or more metal oxides selected from the group consisting of silica, zirconia, alumina and titania on a plastic substrate. It is proposed (for example, refer to patent documents 1). In addition, an anchor coat layer of a metal oxide having a thickness of 0.5 to 5.0 nm is formed between a base film and a thin film layer of a metal such as silicon, aluminum, magnesium, titanium, zirconia, tin, or their oxides. A laminated gas barrier film has been proposed (see, for example, Patent Document 2).

  In recent years, it has been proposed to coat the surface of a plastic container with a DLC (Diamond Like Carbon) film as a means for imparting gas barrier properties to a plastic container (see, for example, Patent Documents 3 and 4). The DLC film is a film having an amorphous three-dimensional structure of carbon atoms and hydrogen atoms, and is a hard carbon film which is hard and has excellent insulation, a high refractive index, and a very smooth morphology. In Patent Document 3, a diamond like carbon (DLC) film having a thickness of 5 to 35 nm is formed on the surface of a plastic container by a plasma chemical vapor deposition (CVD) method. In Patent Document 4, the surface of a polymer substrate is subjected to CVD plasma treatment using a mixed gas of methane and argon to form a carbon interlayer film, and CVD plasma treatment using a hydrocarbon-containing gas is further formed on the carbon interlayer film. Patent Document 1 discloses a technique of forming a DLC film excellent in adhesion on the surface of a polymer substrate by forming a diamond-like carbon film.

  However, while these gas barrier thin film technologies are currently put into practical use mainly with polyethylene terephthalate (PET) substrates, they are used in large quantities throughout the industry, not only in packaging containers, and are versatile polypropylene substrates. Commercialization has not been progressed with polyolefin substrates such as polyethylene substrates. The reason is that, for example, these polyolefin substrates are made of a chemically inert polymer, and the surface tends to be rough due to the influence of the nature and formability of spherulites. Then, the technique of performing a plasma processing on the surface of a polypropylene film for surface activation is disclosed (for example, refer patent document 5). In order to smooth the surface, before forming a vapor-deposited film of silicon oxide by the ion plating method, on the surface of the polypropylene film, one or two kinds of resins are the main components of the vehicle, to which a curing agent is added The technique which provides the plasma-resistant protective layer by the curable resin composition formed by adding is disclosed (for example, refer patent document 6). In addition, on a plastic base mainly composed of polyolefin, a gas barrier coating mainly composed of an alkali metal polysilicate is formed, and in order to improve the adhesion between the gas barrier coating and the plastic base, an alkali metal poly A technique is disclosed in which a nitrogen compound and / or a water-soluble polymer is further incorporated into a silicate (see, for example, Patent Document 7). There has been disclosed a technique of adding a silane coupling agent in order to enhance the adhesive strength between a substrate sheet of olefin resin and a thermoplastic resin layer of olefin resin (see, for example, Patent Document 8). In order to improve adhesion, a transparent primer layer consisting of a compound of a silane coupling agent, an acrylic polyol and an isocyanate compound is provided on the surface of a polypropylene film substrate, and a vapor deposition thin film layer consisting of an inorganic oxide is formed thereon. A technology to provide is disclosed (see, for example, Patent Document 9).

  Furthermore, a hardened layer is formed by condensation reaction as a raw material of a hardened layer covering the surface of a plastic molded body, instead of using a coupling agent having an amino group as a coupling agent, and the hardened layer is There is a technology that plays a role as an adhesion layer and a role as a base layer that favorably expresses the performance of a thin film, and further, the cured layer itself has gas barrier properties (see, for example, Patent Document 12).

JP, 2009-269217, A JP, 2010-605, A JP 2008-230648 A JP 2005-2377 A JP 2008-248374 A Japanese Patent Application Laid-Open No. 11-105218 Japanese Patent Application Laid-Open No. 2002-113826 JP-A-8-230113 Unexamined-Japanese-Patent No. 2000-254994 Japanese Patent Application Publication No. 08-53116 WO 2006/126677 JP 2012-193303 A

  In the gas barrier film described in Patent Document 1, for the purpose of improving the gas barrier property, a metal alkoxide is subjected to a hydrolysis / polycondensation reaction to form a metal oxide structure forming a coating film of the gas barrier property. . Since this hydrolysis / polycondensation reaction requires, for example, a reaction time of 1.5 hours at 110 ° C., processing takes time, and there is a concern that the substrate may be damaged by heat. Also, a gas barrier coating film is formed by a so-called wet method in which a coating solution is applied to a substrate film and dried, which is suitable for forming a film on a planar object such as a plastic film, It is not suitable for forming a film on a three-dimensional object such as a bottle. In the gas barrier film described in Patent Document 2 or Patent Document 6, the thin film is formed using a physical vapor deposition method, but the physical vapor deposition method is expensive because the manufacturing apparatus is expensive and the film forming rate is slow. It can not be said that it is an effective means as a manufacturing method of the plastic molding as a use.

  In Patent Document 5, a so-called weak boundary layer is formed on the surface of the polypropylene by plasma treatment, which may result in insufficient adhesion strength between the polypropylene film and the thin film. In Patent Documents 7 to 9, the silane coupling agent has an intrinsic role, that is, a role of linking the two by bonding to surfaces having different chemical properties by functional groups having different properties respectively at both ends thereof. It's being used. However, none of them mentions that the gas barrier thin film is used as an intermediate layer and is applicable to applications in direct contact with food or beverages.

  Although there are the aforementioned problems, the so-called wet method of applying and drying using a coating solution on the surface of a plastic bottle is active against the inertness or / and the roughness of the surface of the polyolefin substrate described above. And a promising means for forming a gas barrier thin film on a polypropylene substrate or a polyethylene substrate from the viewpoint of simultaneously achieving application of smoothness and leveling and from the viewpoint of not affecting the formability of the container It can be However, the coating solution used has adhesion to both polypropylene and polyethylene and the gas barrier thin film, and can perform high-speed processing capable of following the property of the thin film as an underlayer to develop gas barrier properties and the rate of container production Nature is required. Furthermore, in order to use for containers for drinks and food, safety for the human body is required. As far as the present inventors know, a coating solution applicable to a three-dimensional object such as a container, a treatment method using an underlayer of a gas barrier thin film, and a gas barrier container obtained as a result thereof are not known.

  Patent Document 12 discloses a molded body in which a DLC film is formed after an intermediate layer is formed on a polypropylene substrate, instead of directly forming a DLC film on a polypropylene substrate. By providing the intermediate layer, although the occurrence of cracks in the DLC film can be suppressed, the cracks may remain without disappearing. Therefore, there is a problem that the gas barrier properties can not be sufficiently improved.

  An object of the present disclosure is to provide a coated plastic molded body having further improved gas barrier properties than conventional and a method for producing the same.

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems and found that the coupling agent having an amino group is not used as a coupling agent, and is used as a top coat instead of an intermediate layer. The inventors have found that gas barrier properties can be further improved by forming a layer, and the present invention has been completed. That is, the coated plastic molded body according to the present invention comprises a plastic molded body, a gas barrier thin film which covers the surface of the plastic molded body, and a compound represented by the general formula (Chem. 1) which covers the surface of the gas barrier thin film And a cured layer comprising a condensation polymer of
(Formula 1) R-M- (CH ₃ ) _n (OR ') _3-n
In the general formula (Formula 1), M represents silicon or a metal. R represents a hydrocarbon chain having an amino group. R 'represents a C1-C4 alkyl group. Also, n represents 0, 1 or 2.

  In the coated plastic molded article according to the present invention, it is preferable that the hardened layer is an applied layer, and the condensation polymer intrudes into cracks of the gas barrier thin film. The top coating of the silane coupling agent allows the silane coupling agent to penetrate the cracks in the gas barrier thin film such as a DLC film, making it possible to close the cracks, and oxygen permeation from the cracked part is activated diffusion flow from the capillary flow mechanism It changes to a mechanism and can exhibit high gas barrier properties.

  In the coated plastic molding according to the present invention, the compound represented by the general formula (Formula 1) is N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3. -Aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane Included are forms that are silanes or 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

  In the coated plastic molded product according to the present invention, when the element concentration of M is 1, the hardened layer has an element concentration ratio of 2.0 to 10.2, and C of 4.0 to 15. It is preferable that it is a layer containing 0.6 and 5.1, 6 and N. The layer may be substantially colorless and have high barrier properties and physicochemical stability in an aqueous solution in a weakly acidic to neutral region (hereinafter sometimes referred to as content resistance). .

  In the coated plastic molded body according to the present invention, the plastic molded body includes a form formed of polypropylene, polyethylene, polyethylene terephthalate or a mixture thereof. Even if the plastic molding is a material that is chemically inert and has a relatively rough surface, gas barrier properties can be imparted.

  In the coated plastic molding according to the present invention, the gas barrier thin film includes a form in which it is a DLC film, a SiC film or an oxide film.

  In the coated plastic molding according to the present invention, the surface of the plastic molding is preferably a surface hydrophilized surface. Gas barrier properties can be further enhanced.

  In the coated plastic molded body according to the present invention, the plastic molded body includes a form which is a container. By covering at least one of the inner wall surface or the outer wall surface of the container, it is possible to make the container excellent in the preservation property of the contents.

The method for producing a coated plastic molded body according to the present invention comprises the steps of: forming a gas barrier thin film on the surface of the plastic molded body; and only the compound represented by the general formula (Chem. 1) as a reactant which undergoes a condensation reaction. A coating step of using a solvent-free coating solution on the gas barrier thin film to form a coating layer, and promoting a condensation reaction of the compound to cure the coating layer to form a cured layer And a process in order.
(Formula 1) R-M- (CH ₃ ) _n (OR ') _3-n
In the general formula (Formula 1), M represents silicon or a metal. R represents a hydrocarbon chain having an amino group. R 'represents a C1-C4 alkyl group. Also, n represents 0, 1 or 2.

  In the method for producing a coated plastic molding according to the present invention, it is preferable to have a pre-treatment step of subjecting the surface of the plastic molding to a surface hydrophilization treatment before the film forming step is performed. Furthermore, a coated plastic molded article with improved gas barrier properties can be produced.

  In the method for producing a coated plastic molding according to the present invention, the curing step is preferably a step performed at 0 ° C. or more and 40 ° C. or less. Within this temperature range, the condensation reaction can be prevented from occurring rapidly to form a crack-free cured layer, and the condensation reaction can be completed within a practical time.

  In the method of producing a coated plastic molding according to the present invention, the gas barrier thin film is preferably formed by a chemical vapor deposition method or a physical vapor deposition method. These film forming methods can be applied to various three-dimensional container shapes, and can be formed at low cost as compared with other methods.

  According to the present disclosure, it is possible to provide a coated plastic molded body with further improved gas barrier properties than conventional and a method for producing the same. That is, the gas barrier properties can be further improved by forming a cured layer as a top coat instead of an intermediate layer using the coupling agent having an amino group as a coupling agent, instead of using the coupling agent.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the coating plastic molded object which concerns on this embodiment. It is a graph which shows the relationship between the film thickness of a DLC thin film, and oxygen permeability about Examples 1-6 and Comparative Examples 1-8. 21 is a surface observation image by a laser microscope of Example 4. It is a surface observation image by the laser microscope of comparative example 3. 21 is a surface observation image by AFM of Example 4. It is a surface observation image by AFM of comparative example 3.

  EXAMPLES The present invention will next be described in detail by way of embodiments, which should not be construed as limiting the present invention. The embodiment may be variously modified as long as the effects of the present invention are exhibited.

FIG. 1 is a cross-sectional view showing an example of a coated plastic molding according to the present embodiment. The coated plastic molded body 90 according to the present embodiment is represented by a general formula (Chem. 1), which covers the surface of the plastic molded body 91, the gas barrier thin film 93 covering the surface of the plastic molded body 91, and the gas barrier thin film 93. And a hardened layer 92 made of a condensation polymer of The gas barrier thin film 93 serves as an intermediate layer.
(Formula 1) R-M- (CH ₃ ) _n (OR ') _3-n
In the general formula (Formula 1), M represents silicon or a metal. R represents a hydrocarbon chain having an amino group. R 'represents a C1-C4 alkyl group. Also, n represents 0, 1 or 2.

  The resin constituting the plastic molded body 91 is, for example, polyethylene terephthalate resin (PET), polybutylene terephthalate resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, cycloolefin copolymer resin (COC, cyclic olefin copolymerization), ionomer resin , Poly-4-methylpentene-1 resin, polymethyl methacrylate resin, polystyrene resin, ethylene-vinyl alcohol copolymer resin, acrylonitrile resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyamide resin, polyamideimide resin, polyacetal resin Polycarbonate resin, polysulfone resin, or tetrafluorinated ethylene resin, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin. These can be used in a single layer or in a stack of two or more.

  In the coated plastic molded body 90 according to the present embodiment, the plastic molded body 91 is more preferably made of polypropylene, polyethylene, polyethylene terephthalate or a mixture thereof. Polypropylene includes, for example, homopolymers, random polymers, block polymers. Polyethylene is, for example, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE). In addition, polypropylene, polyethylene, or a mixture thereof is not particularly limited as long as it is mainly composed of polypropylene and polyethylene. For example, the polymer alloy of polypropylene or polyethylene and a resin other than the above-described polypropylene or polyethylene, or polypropylene or polyethylene is obtained by adding various assistants such as an antioxidant, a lubricant, an antiblocking agent, a plasticizer, and a softener.

  In the coated plastic molded body 90 according to the present embodiment, the plastic molded body 91 includes a form that is a container or a film. The container includes a container used in a lid, a stopper or a seal, or a container used in an open state without using them. The size of the opening can be appropriately set according to the contents. The container includes a container having a predetermined thickness having a suitable degree of rigidity and a container formed of a non-rigid sheet material. The contents are, for example, beverages such as water, tea, soft drinks, carbonated beverages or fruit juices, liquids, viscous substances, powders or solid foods. Also, the container may be either a returnable container or a one-way container. Moreover, as a film, a long sheet-like thing and a cut sheet are included. The film may or may not be stretched. In the present embodiment, the shape of the plastic molded body 91 can be appropriately set according to the purpose and application, and is not particularly limited. Further, the present invention is not limited to the method of manufacturing the plastic molded body 91.

  The thickness of the plastic molded body 91 can be appropriately set according to the purpose and application, and is not particularly limited. For the plastic molded body 91 to be, for example, a container such as a beverage bottle, the thickness of the bottle is preferably 100 to 500 μm, more preferably 150 to 300 μm. Moreover, when the plastic molded body 91 is a film which comprises a packaging bag, it is preferable that the thickness of a film is 3-200 micrometers, More preferably, it is 10-100 micrometers.

  In the coated plastic molded body 90 according to the present embodiment, the surface of the plastic molded body 91 is preferably a surface hydrophilized surface. The adhesion between the gas barrier thin film 93 and the plastic molded body 91 is enhanced. Furthermore, when the compound represented by the general formula (Chem. 1) is applied to the surface of the gas barrier thin film 93, the compound penetrates into the cracks of the gas barrier thin film 93, and furthermore, a plastic molded body which is a base of the gas barrier thin film 93 When there is a gap on the surface 91, more specifically, between the gas barrier thin film 93 and the plastic molded body 91, it penetrates to the gap, and the crack can be filled more reliably.

  When the plastic molded body 91 is a container, the gas barrier thin film 93 and the hardened layer 92 are provided on either or both of the inner wall surface and the outer wall surface. When the plastic molded body 91 is a film, the gas barrier thin film 93 and the hardened layer 92 are provided on one side or both sides. In particular, when the plastic molded body 91 is a container for beverage or food, if the gas barrier thin film 93 and the hardened layer 92 are formed on the inner wall surface of the container, the reaction between oxygen etc. dissolved in the container wall and the contents It is possible to effectively suppress the quality deterioration of the contents, such as the sorption of the aroma components to the container wall. On the other hand, when the gas barrier thin film 93 and the hardened layer 92 are formed on the outer wall surface of the container, the gas barrier thin film 93 and the hardened layer 92 can be formed more easily. In particular, when the container material is made of a heat-resistant resin such as polypropylene, it can be a heat-resistant container that enables heat treatment such as boiling sterilization, and it is particularly significant to improve the gas barrier property.

  The type of the gas barrier thin film 93 is not particularly limited, but in addition to the gas barrier property, it has heat resistance and non-sorption, and can utilize the advantages of the plastic molded body 91 and can compensate for the insufficient performance. Preferably, the film is a DLC film, a SiC film, a SiCO film, a SiCN film, or a SiCNO film. Further, in the coated plastic molded body 90 according to the present embodiment, the gas barrier thin film is preferably a DLC film, a SiC film or an oxide film in that it has higher gas barrier properties.

  The thickness of the gas barrier thin film 93 is preferably 1 to 100 nm. More preferably, it is 5-80 nm. If it is less than 0.5 nm, gas barrier properties or other functions may not be obtained. If it exceeds 100 nm, internal stress may cause cracks, and the gas barrier properties or other functions may be degraded.

  The gas barrier thin film 93 can be formed by various known methods. A known method is, for example, a chemical vapor deposition (CVD) method such as a plasma CVD method or a heating element CVD method, a physical vapor deposition (PVD) method such as a vacuum evaporation method, a sputtering method, or an ion plating method. In the present specification, the heating element CVD method refers to a CVD method called a heating element CVD method, a Cat-CVD method or a hot wire CVD method. When the plastic molded body 91 is a container for beverages or food, it is more preferable that it is a plasma CVD method or a heating element CVD method. These can be applied to various three-dimensional container shapes, and can be deposited at low cost as compared with other methods.

  The cured layer 92 is made of a condensation polymer of a compound represented by the general formula (Chem. 1), which covers the surface of the gas barrier thin film 93. The compound represented by General formula (Formula 1) is demonstrated.

  In the general formula (Formula 1), M is silicon (Si) or a metal. The metal is preferably titanium (Ti) or dilnium (Zr). In the present embodiment, M is particularly preferably silicon. An inexpensive compound can be obtained, and the resulting cured layer 92 can be made into a safe and relatively flexible structure.

In the general formula (Formula 1), R is a hydrocarbon chain having an amino group. Amino group, _-NH 2, = NH or -NH-. The amino group is more preferably at the end of the hydrocarbon chain. R is preferably linear and has 3 to 5 carbon atoms. As a result, the resulting hardened layer 92 can be made relatively dense and flexible.

  In general formula (Formula 1), R 'is a C1-C4 alkyl group. Specifically, R 'is a methyl group, an ethyl group, a propyl group or a butyl group. Among these, R 'is more preferably a methyl group. That is, it is preferable that OR 'is a methoxy group. In addition, although it can also be set as the structure which has an acetyl group or an acyl group as R ', it is preferable to set it as an alkyl group from a viewpoint of hardening speed.

  In the general formula (Formula 1), n represents 0, 1 or 2. n is preferably 1, and more preferably 0.

  The compound represented by General formula (Formula 1) can utilize a well-known amine coupling agent. For example, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriol. Ethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxytitanium, 3-amino Propyltrimethoxyzirconium, 3-methacryloxypropyltrimethoxysilane or 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Among these, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-3 in that M is silicon and OR ′ is a methoxy group. Aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane or 3-mercaptopropyltrimethoxysilane Is preferred. In addition, 3-aminopropyltrimethoxysilane is particularly preferable in that M is silicon, OR ′ is a methoxy group, and n is 0.

  When the compound represented by the general formula (Chem. 1) is such that 3-aminopropyltrimethoxysilane, M is silicon, OR 'is a methoxy group, and n is 0, The hardened layer 92 has a high gas barrier property and can have a dense structure. On the other hand, although there is a tendency that the structure is relatively hard and easily cracked, as described above, the hardened layer as the top coat formed on the gas barrier thin film 93 by making the structure of the hydrocarbon chain appropriate. The flexibility of 92 can be secured, and the occurrence of cracks at the time of curing can be suppressed.

  Collectively, the compounds represented by the general formula (Formula 1) are generally used as amine coupling agents, and can be obtained safely and at relatively low cost. At the same time, a certain gas barrier property improvement effect can be expected. Moreover, adhesiveness with the gas barrier thin film 93 can be secured by containing an amino group. Furthermore, in the general formula (Chem. 1), by containing a hydrocarbon chain having OR ′ as a methoxy group, n as 0, and R as the above-mentioned carbon number, the entire compound having an amino group can be subjected to normal temperature and ordinary temperature. The structure can be stably stored under pressure. Then, when a coating liquid comprising the compound represented by the general formula (Chem. 1) is applied to the surface of the gas barrier thin film 93, the compound represented by the general formula (Chem. 1) starts special curing at normal temperature and normal pressure. The condensation reaction proceeds without the agent, and the coating layer can be cured to form the cured layer 92 as a top coat. In relation to these physical properties, the hardened layer 92 can be formed inexpensively and at high speed without using expensive equipment.

  The hardened layer 92 not only plays a role as a protective layer for the gas barrier thin film 93, but also has a role as a repair layer for closing the crack when the condensation polymer enters the crack produced in the gas barrier thin film 93. That is, when the silane coupling agent is top-coated, the silane coupling agent penetrates the cracks of the gas barrier thin film 93 such as a DLC film, and the crack can be closed, and oxygen permeation from the cracked part is activated from the capillary flow mechanism. It can be changed to a chemical diffusion flow mechanism and can exhibit high gas barrier properties. In the hardened layer 92, the alkoxysilane structure (-Si-OR ') in the molecule of the compound represented by the general formula (Chem. 1) is hydrolyzed, for example, by moisture in the air to form a silanol group (-Si-OH). ) Forms a siloxane bond (Si-O-Si) by condensation reaction between molecules. The siloxane bond forms a three-dimensional network, and although the reason is not clear, the cured layer 92 exerts high adhesion with the gas barrier thin film 93 and high gas barrier properties and blocks cracks in the gas barrier thin film 93. At this time, the hardened layer 92 is formed on the gas barrier thin film, thereby smoothing the surface while closing the crack. The compounds represented by the general formula (Formula 1) are generally used as amine coupling agents, but the coupling agents generally have functional groups each having different properties at both ends of the molecular structure. Each functional group has a role of connecting the two by bonding to surfaces having different chemical properties (for example, the surface of an organic substance and the surface of an inorganic substance). Therefore, it is often used mainly as a primer layer or an anchor coat layer for forming a gas barrier thin film. And, in such a general usage method, for example, when the organic substance is polypropylene or polyethylene, it is known that a coupling agent having a vinyl group or a methacryloxy group as a functional group that easily bonds to these is suitable. It is done. However, in the present invention, since a coupling agent having an amino group is selected, it can be said that the coupling agent having an amino group is not used in a general usage method as a coupling agent. In the present invention, by forming the cured layer 92 as a top coat on the gas barrier thin film 93 using a coupling agent having an amino group, the gas barrier thin film 93 is used not only as a protective layer for the gas barrier thin film 93. The condensation polymer intrudes into the crack produced and acts as a repair layer for closing the crack.

  The hardened layer 92 contains M (silicon or metal), O (oxygen), C (carbon), N (nitrogen) and H (hydrogen) as constituent elements. In the coated plastic molded body 90 according to the present embodiment, when the element concentration of M is 1, the hardened layer 92 has O at 2.0 to 10.2, C at 4.0 to 15 at the element concentration ratio. It is preferable that it is a layer containing 0.6 to 5.1 and N. More preferably, when the element concentration of M is 1, the element concentration ratio contains 2.3 to 6.8 O, 4.3 to 8.7 C, and 0.8 to 2.8 N. Do. By making the element concentration of O and the element concentration of C within the above ranges, a physicochemically stable layer can be obtained, even if it is directly or indirectly in contact with the content of weakly acidic to neutral regions rich in beverages or foods. Can. Moreover, the gas barrier property improvement effect of hardened | cured layer 92 itself can be acquired by making element concentration of N into the said range. The adhesion between the gas barrier thin film 93 and the hardened layer 92 can be secured. The measurement of the M, O, C and N element concentrations is preferably performed by using an energy dispersive X-ray fluorescence (EDX) analyzer.

  Next, a method of forming the gas barrier thin film 93 and the hardened layer 92 formed on the surface thereof will be described.

The method for producing a coated plastic molded body according to the present embodiment is represented by a film forming step of forming a gas barrier thin film 93 on the surface of the plastic molded body 91, and a reaction product having a condensation reaction represented by the general formula A coating step of applying only a compound but not using a solvent on the gas barrier thin film 93 to form a coating layer, and promoting a condensation reaction of the compound to cure the coating layer to form a cured layer 92 And curing steps in order.
(Formula 1) R-M- (CH ₃ ) _n (OR ') _3-n
In the general formula (Formula 1), M represents silicon or a metal. R represents a hydrocarbon chain having an amino group. R 'represents a C1-C4 alkyl group. Also, n represents 0, 1 or 2.

(Deposition process)
In the present embodiment, the method for forming the thin film 93 is not particularly limited, and can be appropriately selected according to the type of the gas barrier thin film 93. For example, in the case where the gas barrier thin film 93 is a DLC film, the film can be formed mainly by plasma CVD. For example, JP-A-8-53116, JP-A-8-53117 and JP-A-9-272567 And JP 10-226884. In the case where the gas barrier thin film is a SiC film or an oxide film, the film can be formed by a heat generating body CVD method. For example, WO2006 / 126677, JP2008-127053, JP2008- No.127054.

(Coating process)
Since the compound represented by the general formula (Formula 1) is a compound having a stable and appropriate viscosity, the coating liquid comprising the compound represented by the general formula (Formula 1) can be used as a gas barrier without using a solvent. It can be applied on the surface of the thin film 93. And since a solvent is not used, in the drying after application | coating, gas-barrier property does not fall with the void | hole formed when a solvent volatilizes. The coating step is preferably a method capable of forming a layer on the surface of the gas barrier thin film 93 under normal pressure or reduced pressure. The application method is not particularly limited, and various methods called application or spraying can be used. Specific examples are coating by bar coating, coating by spin coating, coating by spray coating, evaporation or spraying in vacuum, and a method of immersion in a coating solution. The thickness of the coating layer is not particularly limited, but it is preferable that the thickness of the cured layer 92 obtained by curing the coating layer be 0.5 nm to 100 μm. More preferably, it is 5 nm to 30 μm. Particularly preferably, it is 50 nm to 2 μm. If it is less than 0.5 nm, a uniform cured layer 92 may not be obtained. When it exceeds 100 μm, the curing time increases, which is uneconomical.

(Pre-treatment process)
Before performing the film forming process of the gas barrier thin film 93, it is preferable to perform a process of enhancing the wettability on the surface of the plastic molded body 91. Specific examples are plasma treatment with nitrogen, oxygen or argon, corona discharge, ozone treatment, and other various drug treatments. Among these, nitrogen plasma treatment is more preferable. The effect of improving the wettability and the adhesion of the gas barrier thin film 93 can be easily obtained without making the surface of the plastic molded body 91 rough. In addition, when the wettability of the surface of the plastic molded body 91 is improved, the coating liquid flowing in from the crack of the gas barrier thin film 93 penetrates to the gap when there is a gap between the plastic molded body 91 and the gas barrier thin film 93 Becomes easy.

(Curing process)
When the compound represented by the general formula (Chem 1) is applied to the surface of the gas barrier thin film 93 and left under an environment of normal temperature and pressure, the condensation reaction proceeds without the addition of a special curing initiator. , Will be cured. In the method for producing a coated plastic molded product according to the present embodiment, the curing step is preferably a step performed at 0 ° C. or more and 40 ° C. or less. More preferably, it is 10 ° C. or more and 30 ° C. or less. If it is less than 0 ° C., curing takes too much time, and it is difficult to be a practical production method. In particular, it is not practical for packaging applications. If the temperature is higher than 40 ° C., the curing proceeds rapidly, so that the layer obtained is likely to be cracked, and the gas barrier property improving effect and other functions may be deteriorated. Therefore, in order to accelerate the condensation reaction, it is preferable not to perform the acceleration step such as holding at high temperature. The time required for curing varies depending on the temperature at which the curing step is carried out, but is preferably, for example, 30 to 500 minutes.

  Next, the present invention will be described in more detail by way of examples, but the present invention is not construed as being limited to the examples.

Example 1
(Production process of plastic molding)
A 100 μm thick polypropylene film was used as the plastic molding. Using a commercially available press machine (AH-2003 manufactured by As One Corporation), 0.25 g of polypropylene (molecular weight 190,000) manufactured by Sigma Aldrich is used as a polypropylene film first at 180 ° C. for 5 minutes in a mold between stainless steel plates After sandwiching under the conditions weakly, the sandwiching pressure was increased to 8 MPa to form a film of 0.1 mm thickness under the conditions of 180 ° C. for 5 minutes.
(Pre-treatment process)
First, one side of the obtained film was treated with nitrogen plasma for 90 seconds in a plasma ion bombardment apparatus (PIB-10 manufactured by Vacuum Device) to select a hard mode for the output to make it hydrophilic. The current display value at that time was 10 mA.
(Deposition process)
The hydrophilic film was formed into a DLC thin film with a thickness of 100 nm using a parallel plate type plasma CVD apparatus (Custom-built manufactured by Hirano Koh-on). At that time, the pressure in the chamber was reduced to 0.8 Pa. Next, acetylene gas was supplied at a flow rate of 200 ml / min, and a 13.56 MHz high frequency power of 200 W was applied for 36 seconds. After film formation, the formed film was taken out of the chamber.
(Coating process)
Using a spin coater (MS-A100 manufactured by mikasa) on the surface of a DLC thin film, under conditions of 3000 rpm for 1 minute, 3-aminopropyltritri, which is a compound represented by the general formula (Chem. 1) as a coating liquid A coating layer was formed by spin coating using 200 μl of methoxysilane (hereinafter also referred to as APTMS) (KBM 903 manufactured by Shin-Etsu Silicone Co., Ltd.).
(Curing process)
The coated layer was cured in a room at 23 ° C. for 8 hours to form a DLC film on the surface of a polypropylene film, and a coated plastic molded body having a cured layer formed thereon was obtained. The film thickness of the hardened layer after drying was 1 μm.

(Example 2)
A coated plastic molding was obtained in the same manner as in Example 1 except that the film thickness of the DLC thin film was 5 nm and the high frequency application time was 2 seconds in Example 1.

(Example 3)
A coated plastic molded body was obtained in the same manner as in Example 1 except that the film thickness of the DLC thin film was 1 nm and the high frequency application time was 0.5 seconds in Example 1.

(Example 4)
A coated plastic molding was obtained in the same manner as in Example 1 except that the pretreatment step was not performed in Example 1.

(Example 5)
A coated plastic molding was obtained in the same manner as in Example 2 except that the pretreatment step was not performed in Example 2.

(Example 6)
A coated plastic molding was obtained in the same manner as in Example 3 except that the pretreatment step was not performed in Example 3.

(Example 7)
A coated plastic molding was carried out in the same manner as in Example 4 except that 3-aminopropyltriethoxysilane (hereinafter also referred to as APTES) (KBE 903 manufactured by Shin-Etsu Silicone Co., Ltd.) was used instead of APTMS in Example 4. I got

(Example 8)
A coated plastic molding was obtained in the same manner as in Example 4 except that 3-methacryloxypropyltrimethoxysilane (KBM 503 manufactured by Shin-Etsu Silicone Co., Ltd.) was used instead of APTMS.

(Example 9)
A coated plastic molding was carried out in the same manner as in Example 4, except that N-2- (aminoethyl) -3-aminopropyltrimethoxysilane (KBM603 manufactured by Shin-Etsu Silicone Co., Ltd.) was used instead of APTMS. I got

(Example 10)
A coated plastic molding was obtained in the same manner as in Example 4 except that 3-mercaptopropyltrimethoxysilane (KBM 803 manufactured by Shin-Etsu Silicone Co., Ltd.) was used in place of APTMS.

(Example 11)
A coated plastic molded body is obtained in the same manner as in Example 4 except that 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBM303 manufactured by Shin-Etsu Silicone Co., Ltd.) is used in place of APTMS. The

(Example 12)
A 100 μm thick high density polyethylene film was used as a plastic molding. The high density polyethylene film was prepared by first using 0.25 g of Sigma-Aldrich polypropylene (melt index 12 g / 10 min, 190 ° C./2.16 kg) and a commercially available press (AH-2003 manufactured by As One Corporation). After sandwiching weakly in a mold between stainless steel plates at 150 ° C. for 5 minutes, the sandwiching pressure was increased to 8 MPa to form a film of 0.1 mm thickness at 150 ° C. for 5 minutes. A coated plastic molding was obtained in the same manner as in Example 4 except that the above-mentioned high density polyethylene film was used in place of the polypropylene film in Example 4.

(Comparative example 1)
The polypropylene film produced in Example 1 was used as a measurement sample as it was without hydrophilization treatment.

(Comparative example 2)
The high density polyethylene film produced in Example 1 was used as a measurement sample as it was without hydrophilization treatment.

(Comparative example 3)
A measurement sample was obtained in the same manner as in Example 4 except that the cured layer was not provided in Example 4.

(Comparative example 4)
A measurement sample was obtained in the same manner as in Example 5 except that the hardened layer was not provided in Example 5.

(Comparative example 5)
A measurement sample was obtained in the same manner as in Example 6 except that the cured layer was not provided in Example 6.

(Comparative example 6)
A measurement sample was obtained in the same manner as in Example 1 except that the cured layer was not provided in Example 1.

(Comparative example 7)
A measurement sample was obtained in the same manner as in Example 2 except that the hardened layer was not provided in Example 2.

(Comparative example 8)
A measurement sample was obtained in the same manner as in Example 3 except that the cured layer was not provided in Example 3.

(Comparative example 9)
A measurement sample was obtained in the same manner as in Example 1 except that the DLC thin film was not provided in Example 1. This sample is provided with a hardened layer on the surface of a plastic molding.

(Comparative example 10)
(Production process of plastic molding)
A 100 μm thick polypropylene film was used as the plastic molding. Using a commercially available press machine (AH-2003 manufactured by As One Corporation), 0.25 g of polypropylene (molecular weight 190,000) manufactured by Sigma Aldrich is used as a polypropylene film first at 180 ° C. for 5 minutes in a mold between stainless steel plates After sandwiching under the conditions weakly, the sandwiching pressure was increased to 8 MPa to form a film of 0.1 mm thickness under the conditions of 180 ° C. for 5 minutes.
(Pre-treatment process)
First, one side of the obtained film was treated with nitrogen plasma for 90 seconds in a plasma ion bombardment apparatus (PIB-10 manufactured by Vacuum Device) to select a hard mode for the output to make it hydrophilic. The current display value at that time was 10 mA.
(Coating process)
Using a spin coater (MS-A100 manufactured by mikasa) on the surface of a polypropylene film which has been subjected to a hydrophilization treatment without performing the film forming step of the gas barrier thin film, a general formula ((coating solution) under the conditions of 3000 rpm for 1 minute The coating layer was formed by spin coating using 200 μl of 3-aminopropyltriethoxysilane (KBE 903 manufactured by Shin-Etsu Silicone Co., Ltd.), which is a compound represented by Chemical Formula 1).
(Curing process)
The coated layer was cured in a room at 23 ° C. for 8 hours to obtain a coated plastic molding having a cured layer formed on the surface of a polypropylene film. The film thickness of the hardened layer was 1 μm.

(Comparative example 11)
(Production process of plastic molding)
A 100 μm thick polypropylene film was used as the plastic molding. Using a commercially available press machine (AH-2003 manufactured by As One Corporation), 0.25 g of polypropylene (molecular weight 190,000) manufactured by Sigma Aldrich is used as a polypropylene film first at 180 ° C. for 5 minutes in a mold between stainless steel plates After sandwiching under the conditions weakly, the sandwiching pressure was increased to 8 MPa to form a film of 0.1 mm thickness under the conditions of 180 ° C. for 5 minutes.
(Pre-treatment process)
First, one side of the obtained film was treated with nitrogen plasma for 90 seconds in a plasma ion bombardment apparatus (PIB-10 manufactured by Vacuum Device) to select a hard mode for the output to make it hydrophilic. The current display value at that time was 10 mA.
(Coating process)
Using a spin coater (MS-A100 manufactured by mikasa) on the surface of a hydrophilized film, 3-amino which is a compound represented by the general formula (Chem. 1) as a coating solution under conditions of 3000 rpm and 1 minute A coated layer was formed by spin coating using 200 μl of propyltrimethoxysilane (KBM 903 manufactured by Shin-Etsu Silicone Co., Ltd.).
(Curing process)
The coated layer was cured in a room at 23 ° C. for 8 hours. The film thickness of the hardened layer was 1 μm.
(Deposition process)
The film was placed in a vacuum chamber in a parallel plate plasma CVD apparatus (Hirano Koh-on Custom-built), and the pressure was reduced until it reached 0.8 Pa. Next, acetylene gas was supplied at a flow rate of 200 ml / min, and 200 W of 13.56 MHz high frequency power was applied for 32 seconds. After film formation, the film on which the DLC thin film was formed was taken out from the vacuum chamber.

(Comparative example 12)
A measurement sample is obtained in the same manner as in Comparative Example 12 except that 3-aminopropyltriethoxysilane (KBE 903 manufactured by Shin-Etsu Silicone Co., Ltd.) is coated in place of 3-aminopropyltrimethoxysilane in Comparative Example 11 in the coating step. The

(Comparative example 13)
The high density polyethylene film produced in Example 12 was used as a measurement sample as it was without hydrophilization treatment.

  The sample preparation conditions and the oxygen permeability are shown in Table 1 for Examples and Comparative Examples.

  FIG. 2 shows the relationship between the film thickness of the DLC thin film and the oxygen permeability in Examples 1 to 6 and Comparative Examples 1 to 8. In FIG. 2, a polypropylene film not subjected to hydrophilic treatment is denoted as PP, and a polypropylene film subjected to hydrophilic treatment as pt-PP. The layer relationship is described in order from the upper layer and divided by /.

(Gas barrier property)
The oxygen permeability is measured using an oxygen permeability measuring device (model: Oxtran 2/21, manufactured by Modern Control) under conditions of 23 ° C., 90% RH, conditioned for 5 hours from the start of measurement, and the measurement started The value after 6 hours from

(Element concentration)
The element concentration of the hardened layer was measured for Example 1, Example 4, Example 7 and Example 12. The element concentration is EDX analysis using an EDX apparatus (EMAX X-Max manufactured by Horiba, Ltd.) in a field of view (100 μm square) where the surface of the hardened layer is magnified 1000 times with a scanning electron microscope (SU1510 manufactured by Hitachi High-Technologies Corp.) Did. The conditions for EDX analysis are as follows. The analysis was performed on three places while changing the part to be observed. Table 2 shows the ratio of the element concentration of O, C and N when the element concentration of M is 1.
Acceleration voltage: 8.0kV
Measurement pressure: 60Pa
Probe current: 67.0 μA

(Surface observation 1)
The surface observation image by the laser microscope of Example 4 is shown in FIG. The surface observation image by the laser microscope of the comparative example 3 is shown in FIG.

(Surface observation 2)
The surface observation image by AFM of Example 4 is shown in FIG. The surface observation image by AFM of the comparative example 3 is shown in FIG.

(Wetability)
The sample of Comparative Example 1 (referred to as Sample 1), the sample of Comparative Example 1 subjected to the pre-treatment step similar to Example 1 and subjected to hydrophilic treatment (referred to as Sample 2) and Comparative Example 3 (referred to as Sample 3) The contact angle measurement (droplet method) of APTMS was performed. APTMS used the APTMS used in the application step of Example 1 as a droplet. The contact angle was measured by the droplet method in accordance with JIS R3257. The results are shown in Table 3. The results shown in Table 3 indicate that APTMS has high wettability to the hydrophilized polypropylene film and DLC thin film. Structural analysis of the surface of the DLC thin film by XPS suggested the presence of hydrophilic groups on the surface of the DLC thin film.

  Referring to FIG. 2, in comparison with Comparative Examples 1 to 8, Examples 4 to 6 (denoted as APTMS / DLC / PP) have gas barrier properties to those having the same DLC thin film thickness. It was improving. Furthermore, in Examples 1 to 3 (expressed as APTMS / DLC / pt-PP) in which a polypropylene film was subjected to a hydrophilization treatment, the gas barrier properties were further improved as compared with Examples 4 to 6. In Examples 1 to 6, as the film thickness of the DLC thin film is larger, the gas barrier property is improved. As in Example 3 and Example 6, even a thin DLC film of 1 nm can exhibit gas barrier properties, and can reduce coloration due to the DLC thin film.

  When Comparative Example 1 and Comparative Example 9 are compared, it can be seen that providing a 1 μm thick cured layer hardly contributes to the improvement of the gas barrier properties. On the other hand, when Example 4 and Comparative Example 3 are compared, the gas barrier property is greatly improved by providing a 1 nm thick cured layer as a top coat. Thus, it has been found that using APTMS as a top coat improves barrier properties more than using it as an intermediate layer.

  Furthermore, when FIG. 3 and FIG. 4 are compared, the hardened layer entered the crack of the DLC thin film by providing the hardened layer, and the entire surface of the hardened layer including the portion other than the crack portion was smoothed. I understood it. When FIG. 5 and FIG. 6 were compared, it turned out that the hardened layer fills the unevenness | corrugation of a DLC thin film, and surface roughness is reduced by providing a hardened layer. Thus, even if the hardened layer is a thin layer of about 1 μm, it is considered that the gas barrier property is improved by the hardened layer entering the cracks of the DLC thin film.

  Then, referring to Table 3, since APTMS has high wettability to the hydrophilized polypropylene film and DLC thin film, it is considered that Example 1 has very high gas barrier properties. That is, when the wettability of the surface of the polypropylene film is improved, not only the coating solution flows into the cracks of the gas barrier thin film 93, but also when there is a gap between the plastic molded body 91 and the gas barrier thin film 93 It is considered that the gas barrier property is further improved because the gas enters the gap.

  In Examples 1, 4 and 12, no significant difference was found in the element concentration ratio regardless of the substrate. From this, it is considered that the composition of the outermost surface of APTMS becomes almost constant regardless of the substrate.

  As shown in Example 12, even when a high density polyethylene film was used as a substrate, improvement in the gas barrier properties could be confirmed.

  The coated plastic molding according to the present invention has gas barrier properties and resistance to content in the weakly acidic to neutral region, and in particular, containers for beverages such as water, tea, soft drinks, carbonated beverages, fruit juices, tablets and the like It is suitable as a packaging material for solid pharmaceutical containers and food containers.

90 Coated plastic molded body 91 Plastic molded body 92 Hardened layer 93 Gas barrier thin film

Claims (12)

Plastic molded body,
A gas barrier thin film for covering the surface of the plastic molded body,
What is claimed is: 1. A coated plastic molded article comprising: a cured layer formed of a condensation polymer of a compound represented by the general formula (Chem. 1), which covers the surface of the gas barrier thin film.
(Formula 1) R-M- (CH ₃ ) _n (OR ') _3-n
In the general formula (Formula 1), M represents silicon or a metal. R represents a hydrocarbon chain having an amino group. R 'represents a C1-C4 alkyl group. Also, n represents 0, 1 or 2.   The coated plastic molding according to claim 1, wherein the cured layer is a coating layer, and the condensation polymer is intruded in the crack of the gas barrier thin film.   The compound represented by the general formula (Formula 1) is N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-amino Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane or 2- (3,4-epoxy) The coated plastic molding according to claim 1 or 2, which is cyclohexyl) ethyltrimethoxysilane.   When the element concentration of M is 1, the hardened layer has an element concentration ratio of 2.0 to 10.2, O of 4.0 to 15.6, C of 0.6 to 5. The coated plastic molded body according to any one of claims 1 to 3, which is a layer containing one.   The coated plastic molded body according to any one of claims 1 to 4, wherein the plastic molded body is made of polypropylene, polyethylene, polyethylene terephthalate or a mixture thereof.   The coated gas-barrier molded article according to any one of claims 1 to 5, wherein the gas barrier thin film is a DLC film, a SiC film or an oxide film.   The coated plastic molded body according to any one of claims 1 to 6, wherein the surface of the plastic molded body is a surface hydrophilized surface.   The coated plastic molded body according to any one of claims 1 to 6, wherein the plastic molded body is a container. A film forming step of forming a gas barrier thin film on the surface of the molded plastic;
Applying a coating solution using no solvent, using only the compound represented by the general formula (Chem. 1) as a reactant to undergo a condensation reaction, on the gas barrier thin film to form a coating layer;
A curing step of promoting the condensation reaction of the compound and curing the coated layer to form a cured layer, and the method further comprises the steps of:
(Formula 1) R-M- (CH ₃ ) _n (OR ') _3-n
In the general formula (Formula 1), M represents silicon or a metal. R represents a hydrocarbon chain having an amino group. R 'represents a C1-C4 alkyl group. Also, n represents 0, 1 or 2.   The method for producing a coated plastic molded body according to claim 9, further comprising a pretreatment step of subjecting the surface of the plastic molded body to a surface hydrophilization treatment before the film forming step is performed.   The method for producing a coated plastic molding according to claim 9, wherein the curing step is a step performed at 0 ° C or more and 40 ° C or less.   The method according to claim 9 or 10, wherein the gas barrier thin film is formed by a chemical vapor deposition method or a physical vapor deposition method.