JP2006052298A - Coating liquid and vapor-deposited film having protective layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating liquid forming a protective layer of a vapor-deposited film having resistance to solvents used in a printing ink, slightly causing leveling trouble after transfer of the printing ink, affording an excellent print and preventing the lowering of gas barrier properties of a vapor-deposited thin-film layer by printing. <P>SOLUTION: The coating liquid comprises a poly(meth)acrylic acid or an acrylic or a methacrylic acid/an acrylic ester or a methacrylic ester copolymer containing ≥10 mass% of the acrylic acid or methacrylic acid and a polyurethane-urea resin having ether bonds as film-forming components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating solution for forming a protective layer on the surface of a deposited thin film layer of a deposited film on which a metal oxide deposited thin film layer such as alumina or silicon oxide is formed.

  A vapor-deposited film in which a vapor-deposited thin film layer of aluminum, silicon oxide or aluminum oxide is formed on a film such as PET (polyethylene terephthalate) or NY (nylon) is excellent in gas barrier properties, decorative properties, light blocking properties, flexibility, etc. Therefore, it is often used for food packaging. Usually, these deposited thin film layers are often printed.

  It is known that when the gravure printing is performed on the vapor-deposited thin film layer, the gas barrier property is lowered due to the influence of the colorant (pigment) in the printing ink composition. Yes. Conventionally, polyester resins and polyurethane / urea resins have been used for forming the protective layer. These resins have a molecular weight of several tens of thousands, are dissolved in a solvent, and are used as a one-component or two-component coating solution.

  However, the protective layer immediately after being formed by applying these coating liquids has low resistance to the solvent used in the printing ink, and as a result, the printing ink has poor transferability, and the printed matter has high design properties. There is a disadvantage that it cannot be obtained. For this reason, the actual situation is that the coating solution is made into a two-component specification and this defect is compensated by aging. Aging with a two-component specification requires separate coating and aging processes, and therefore the protective layer formation and printing cannot be performed continuously, resulting in reduced productivity and increased cost. In addition, as another method, there is also the use of a coating solution using solvent-resistant PVA (polyvinyl alcohol), but the coating solution is an aqueous solution of PVA, and it is necessary to dry the coating film at a high temperature. However, there is a problem of introducing large-scale equipment or low-speed machining.

  The present invention has been made in view of the above circumstances, and the problem of the present invention is that it has resistance to the solvent used in the printing ink, has few leveling obstacles after transfer of the printing ink, and is excellent in printed matter. It is possible to provide a coating liquid that can form a protective layer for a vapor deposition film in which deterioration of gas barrier properties of the vapor deposition thin film layer due to printing can be prevented.

  As a result of repeated studies to achieve the above-mentioned problems, the inventor has adhered a film made of a mixture of a polymer such as poly (meth) acrylic acid and a certain type of polyurethane / urea resin to the deposited thin film layer. Excellent resistance to solvents such as ethyl acetate, methyl ethyl ketone, and toluene used in printing inks. Films made of the above resin mixture have few leveling obstacles after transfer of printing ink and provide excellent printed matter. It was found that the gas barrier property of the deposited thin film layer was not reduced by printing.

The present invention has the following configuration.
1. Poly (meth) acrylic acid or (meth) acrylic acid / (meth) acrylic acid ester copolymer containing 10% by mass or more of (meth) acrylic acid (hereinafter collectively referred to as “(meth) acrylic acid resin”) And a polyurethane / urea resin having an ether bond as a film-forming component.
2. 2. The coating liquid according to 1 above, which contains a crosslinking agent.
3. 3. The coating solution as described in 2 above, wherein the crosslinking agent is a bifunctional or higher functional epoxy resin, polyisocyanate or block polyisocyanate.
4). 3. The coating liquid according to 1 or 2 containing a silane coupling agent.
5. The vapor deposition film characterized by having a protective layer formed from the coating liquid of any one of said 1-4 on the metal oxide vapor deposition film surface of a vapor deposition film.
In the present invention, “(meth) acrylic acid” means both acrylic acid and methacrylic acid.

  The protective layer of the vapor-deposited film consisting of (meth) acrylic acid-based resin and polyurethane / urea resin with ether bond does not deteriorate the gas barrier property of the vapor-deposited thin film layer by printing the printing ink on the surface. Maintains adhesion to the thin film layer. The protective layer is resistant to the solvent used in the printing ink even immediately after formation, and when printing, the first color is printed on the protective layer, and after that, even if normal printing is performed, the printed matter is excellent without impairing the printing effect As a result, the production can be rationalized, and the cost is lower than the method of forming the protective layer and printing in separate steps. Since the coating liquid for forming the protective layer of the vapor-deposited film of the present invention is dissolved in a quick-drying solvent, no special drying equipment is required.

  The coating liquid of the present invention uses (1) (meth) acrylic acid resin and (2) polyurethane-urea resin having an ether bond as a film forming component. The (meth) acrylic acid resin has excellent adhesion to the deposited thin film layer, and has resistance to solvents such as ethyl acetate, methyl ethyl ketone, and toluene used in printing inks. Has less leveling hindrance after the transfer of printing ink and can provide excellent printed matter. However, the film is hard and brittle, and is not preferable as a protective layer for the deposited thin film layer. Polyurethane / urea resin, on the other hand, is flexible and has the necessary performance as a protective layer, but is soluble in ethyl acetate, methyl ethyl ketone, and toluene used in printing inks. On the surface of the film, leveling failure after transfer of the printing ink occurs, and an excellent printed matter cannot be obtained.

  As a result of various investigations, among polyurethane / urea resins, polyurethane / urea resins having an ether bond in the molecule are miscible (compatible) in a wide range of mixing ratios with (meth) acrylic acid resins. The film made of a mixture is flexible, resistant to solvents such as ethyl acetate, methyl ethyl ketone, and toluene used in printing inks, without any leveling problems after printing ink transfer, and deposited thin film after printing It was found that there was no decrease in gas barrier properties of the layer.

  (Meth) acrylic acid resins used in the present invention include (meth) acrylic acid homopolymers and copolymers of (meth) acrylic acid and (meth) acrylic acid esters (hereinafter simply referred to as “acrylic copolymers”). "). The homopolymer of (meth) acrylic acid to be used preferably has an average molecular weight in the range of 10,000 to 60,000. Moreover, the copolymerization ratio of (meth) acrylic acid and (meth) acrylic acid ester in the acrylic copolymer decreases the solvent resistance as the ratio of (meth) acrylic acid ester increases, and (meth) acrylic acid When the ratio is high, the solvent resistance increases, but (meth) acrylic acid needs to be 10% by mass or more. If the (meth) acrylic acid is less than 10% by mass, the effect of the present invention cannot be obtained. As the (meth) acrylic acid ester, a (meth) acrylic acid alkyl ester is preferable, and examples of the alkyl group include a methyl group, an ethyl group, a butyl group, a 2-ethylhexyl group, a lauryl group, and other alkyl groups. These acrylic copolymers preferably have an average molecular weight in the range of 10,000 to 60,000.

  The polyurethane-urea resin used in the present invention must have an ether bond in its structure. The ether bond is brought about by using a polyol having an ether bond as a raw material of the polyurethane / urea resin, but it is not necessary for all polyols to have an ether bond. Even if it is a carbonate bond, there is no problem.

  As the polyol having an ether bond, any conventionally known polyether polyols such as polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can be used, and are not particularly limited. The mixing ratio of these ether polyols and other polyols is arbitrary. When emphasizing miscibility with (meth) acrylic acid-based resins, the coating ratio (protective layer) can be increased by increasing the proportion of ether-based polyols, and when emphasizing solvent resistance, the proportion of other polyols is increased. The performance of the can be controlled freely.

  The ether-based polyol and other polyols may be used in combination when synthesizing a polyurethane / urea resin, or each polyurethane / urea resin is synthesized using each polyol, and the resulting polyurethane / urea is synthesized. You may mix and use resin. In any case, the amount of the polyol having an ether bond is preferably 20 to 100% by mass of the total polyol. When the amount of the polyol having an ether bond is less than 20% by mass, it is not preferable in terms of the mixing property with the (meth) acrylic acid resin. The molecular weight of the polyurethane-urea resin is not particularly limited, but the average molecular weight is usually preferably in the range of 10,000 to 50,000.

  The (meth) acrylic acid resin (1) and the polyurethane-urea resin (2) having an ether bond can be mixed at any ratio, and the mixing ratio can be freely selected from the transferability of printing ink and the function of protecting the deposited film layer. I can decide. The mixing mass ratio of (1) and (2) is preferably in the range of 5:95 to 95: 5.

  By forming the protective layer at a mixing ratio in the above range, the protective layer has sufficient functions, but has a bifunctional or higher functional epoxy resin as a crosslinking agent (curing agent) for the purpose of increasing resistance to the ink solvent. A protective layer having high physical properties can be obtained by adding polyisocyanate or the like. Furthermore, water resistance can be improved by adding a silane coupling agent.

  Examples of the crosslinking agent (curing agent) used in the present invention include an epoxy resin having two or more epoxy groups, a polyisocyanate having two or more isocyanate groups, and a block polyisocyanate. It can be used and is not particularly limited. The amount of the crosslinking agent to be used is not particularly limited, and is usually about 5 to 20% by mass with respect to the film forming component (the polymer mixture) in the coating solution.

  Examples of the silane coupling agent used in the present invention include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxymethoxysilane, γ-mercaptopropyltrimethoxysilane, N-β- ( Hydrolysis of aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. Any of those having a functional alkoxysilyl group can be used. The usage-amount of a silane coupling agent is not restrict | limited in particular, Usually, it is about 5-20 mass% with respect to the film formation component (said polymer mixture) in a coating liquid.

  The coating liquid used to form the protective layer on the vapor-deposited film of the present invention is a common film-forming component (meth) acrylic resin (1) and polyurethane-urea resin (2) having an ether bond. The solution can be dissolved together in a solvent, or each can be dissolved in a separate solvent (soluble in each other) to form a solution, and these solutions can be mixed. It is not particularly limited.

  As a soluble solvent of (meth) acrylic acid resin, for example, an alcohol solvent such as methanol, ethanol, isopropyl alcohol, propylene glycol monomethyl ether, etc., as a soluble solvent of polyurethane-urea resin having an ether bond, for example, Examples thereof include ester solvents such as ethyl acetate and normal propyl acetate, ketone solvents such as methyl ethyl ketone, and mixed solvents of these with alcohol solvents. If necessary, additives such as the above-mentioned crosslinking agent, silica, fatty acid amide, polyethylene wax and the like can be appropriately added to the coating solution. The coating liquid is usually adjusted to a solid content of about 5 to 15% by mass.

In order to form a protective layer on the surface of the vapor-deposited film, using a normal coating means such as gravure coating, roll coating, gravure reverse coater, the coating amount is, for example, A coating solution is applied to the surface of the deposited film so as to be about 0.1 to 1 g / m ² (dry). After the application is completed, it is dried appropriately. In this invention, a vapor deposition film is not specifically limited, Any may be sufficient if it has a metal oxide vapor deposition thin film layer.

  EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these Examples. In the following examples, the mixing ratio, part and% are all based on mass.

Examples 1-3, Comparative Examples 1-2
Polymethacrylic acid having an average molecular weight of 30,000 is prepared, and as a polyurethane / urea resin, a polyester polyol (average molecular weight) obtained by polymerization of polypropylene glycol (average molecular weight 2,000), neopentyl glycol and adipic acid. 2,000) is mixed with a 1: 9 mixture of isophorone diisocyanate so that the equivalent ratio of NCO / OH is 3: 2. In addition, a polyurethane-urea resin having an amino group at the terminal obtained by elongation was prepared.

The polymethacrylic acid was dissolved in isopropyl alcohol, and the polyurethane-urea resin was dissolved in a 2: 2: 1 mixed solvent of ethyl acetate / methyl ethyl ketone / isopropyl alcohol (solid content 30% each). These solutions were mixed to prepare a solution containing the above polymer at a mixing ratio shown in Table 1 below, and a coating solution having a solid content of 15% was prepared with a 1: 1 mixed solvent of ethyl acetate / isopropyl alcohol. Apply each coating solution to Ecosia VN200 (deposited film manufactured by Toyobo Co., Ltd .: silica and alumina deposited on nylon film) using a gravure printing machine so that the coating amount is 0.5 g / m ² (dry). Thus, a protective layer was formed. Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 1 below.

Examples 4-6, Comparative Examples 3-4
To each coating liquid of Examples 1 to 3 and Comparative Examples 1 to 2, an epoxy curing agent (Epototo YP300, non-volatile content 100%: manufactured by Toto Chemical Co., Inc.) is added 10% with respect to the solid content of the coating liquid, A protective layer was formed in the same manner as in Example 1 and the performance was evaluated by printing and dry laminating by the methods described below. The obtained results are shown in Table 2 below.

Examples 7-9, Comparative Examples 5-6
10% of polyisocyanate (Takenate D160N, non-volatile content 75%, manufactured by Mitsui Takeda Chemical Co., Ltd.) was added to each of the coating liquids of Examples 1 to 3 and Comparative Examples 1 and 2 with respect to the solid content of the coating liquid. A protective layer was formed in the same manner as in Example 1. Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 3 below.

Examples 10-12, Comparative Examples 7-8
Block polyisocyanate (Takenate B800, nonvolatile content 50%: manufactured by Mitsui Takeda Chemical Co., Ltd.) is added to each coating solution of Examples 1 to 3 and Comparative Examples 1 to 2 to the solid content of the coating solution, After coating in the same manner as in Example 1 and the like, it was ignited at 160 ° C. for 10 minutes to form a protective layer. Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 4 below.

Examples 13-15, Comparative Examples 9-10
As a copolymer of methacrylic acid and ethyl methacrylate, a copolymer (average molecular weight of 30,000) comprising methyl methacrylate / n-butyl methacrylate / methacrylic acid of 4/3/3 (mass ratio) was prepared, and As a polyurethane-urea resin, a 1: 1 mixture of polypropylene glycol (average molecular weight 2,000) and polycaprolactone diol (average molecular weight 1,000) and isophorone diisocyanate have an NCO / OH (equivalent ratio) of 3: 2. A polyurethane-urea resin having an amino group at the terminal was prepared by adding 1.1 times the equivalent of isophorone diamine to the terminal isocyanate prepolymer obtained by the reaction as described above.

The above copolymer was dissolved in a 1/1 mixed solvent of ethyl acetate / isopropyl alcohol, and the polyurethane-urea resin was dissolved in a 2: 2: 1 mixed solvent of ethyl acetate / methyl ethyl ketone / isopropyl alcohol (both solid contents were 30). %). These solutions were mixed such that the polymer had a mixing ratio shown in Table 5 to obtain a coating solution. Each coating solution is adjusted to a solid content of 15% with a 1: 1 mixed solvent of ethyl acetate / isopropyl alcohol, and applied to Ecosia VN200 (deposited film manufactured by Toyobo Co., Ltd.) using a gravure printer. / M ² (dry) was applied to form a protective layer. Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 5 below.

Examples 16-18, Comparative Examples 11-12
10% of the solid content of the epoxy-based curing agent (Epototo YP300: manufactured by Toto Chemical Co., Inc.) coating solution was added to each coating solution of Examples 13 to 15 and Comparative Examples 9 to 10, and the same as Example 13 Thus, a protective layer was formed. Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 6 below.

Examples 19-21, Comparative Examples 13-14
A silane coupling agent (Shin-Etsu Silicon KBM403, non-volatile content: 100%: Shin-Etsu Chemical Co., Ltd.) is applied to each coating solution of Examples 4 to 6 and Comparative Examples 3 to 4 with respect to the solid content of the coating solution. And a protective layer was formed in the same manner as in Examples 1 to 3 and Comparative Examples 1 and 2. Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 7 below.

Comparative Examples 15-19
As a copolymer of methacrylic acid and ethyl methacrylate, a copolymer (average molecular weight of 30,000) comprising 50/50/1 (mass ratio) of methyl methacrylate / n-butyl methacrylate / methacrylic acid is prepared, and As a polyurethane-urea resin, a 1: 1 mixture of polypropylene glycol (average molecular weight 2,000) and polycaprolactone diol (average molecular weight 1,000) and isophorone diisocyanate have an NCO / OH (equivalent ratio) of 3: 2. A polyurethane-urea resin having an amino group at the terminal was prepared by adding 1.1 times the equivalent of isophorone diamine to the terminal isocyanate prepolymer obtained by the reaction as described above.

The above copolymer was dissolved in a mixed solvent of ethyl acetate / isopropyl alcohol 1/1, and the polyurethane / urea resin was dissolved in a mixed solvent 2: 2: 1 of ethyl acetate / methyl ethyl ketone / isopropyl alcohol (both solid contents were Adjusted to 30 parts). These solutions were mixed so that the above polymer had a mixing ratio shown in Table 8 below, and adjusted to a coating solution having a solid content of 15% with a 1: 1 mixed solvent of ethyl acetate / isopropyl alcohol. The protective layer was formed by applying to Ecosia VN200 (deposited film manufactured by Toyobo Co., Ltd.) so that the coating amount was 0.5 g / m ² (dry). Printing and dry lamination were performed by the method described below, and performance evaluation was performed. The obtained results are shown in Table 8 below.

Comparative Example 20
The film in which the protective layer was not formed (Ecosia VN200 (deposited film manufactured by Toyobo Co., Ltd.)) was subjected to printing and dry laminating in the same manner as in each Example, and performance evaluation was performed.

<Performance evaluation of protective layer>
Immediately printing was performed on the prepared protective layer (in Comparative Example 20, since the protective layer was not formed, and the surface of the deposited film). After one day, dry lamination was processed, and performance evaluation was performed after curing at 40 ° C. for 48 hours.
The ink used is NT Hiramic 701R White (manufactured by Dainichi Seika Kogyo Co., Ltd .: a composition in which titanium oxide is dispersed in a urethane / urea resin with a polyester skeleton), and the dry laminating agent is Seika Bond A154-2 / C88F (manufactured by Dainichi Seika Kogyo Co., Ltd.). : Composition of terminal isocyanate and terminal hydroxyl group in the PPG skeleton). The laminated film is LLDPE (Toyobo Co., Ltd. L4104: 40 μm thickness).

<Performance judgment method>
Adhesiveness: Judged by peeling the cellophane tape in the dry state of the protective layer.
○: No peeling Δ: About 50% peeling ×: 80% or more peeling Ink transferability: Judgment was made by comparing the concentration of the gravure halftone plate 10 to 100%.
○: Same as the non-coated surface (film surface) △: Less than 10-20% compared to the film surface ×: 20% decreased compared to the film surface Water resistance: The deposited film on which the protective layer is formed in water After immersion for 1 hour, the sample was taken out and judged by peeling the cellophane tape in a wet state.
○: No peeling Δ: About 50% peeling ×: 80% or more peeling Boil resistance: The laminate was immersed in warm water at 95 ° C. for 30 minutes, and judged from whitening of the protective layer.
◯: No whitening of coating film Δ: Slightly lower haze of coating film ×: Whitening of coating film and opaque barrier property: Judged from change in oxygen permeability.
Peel strength: The laminate was peeled between Ecosial VN200 (manufactured by Toyobo Co., Ltd.) and LLDPE, and the strength of the laminate was measured.
Seal strength: LLDPE surfaces of the laminate were heat-sealed at 150 ° C., 0.3 MPa, and 1 second, and the tensile strength of the heat-sealed portion was measured.

  From the above results, the protective layer of the vapor deposition film formed from the coating liquid containing (meth) acrylic acid resin and polyurethane / urea resin has the transferability of gravure printing ink and the laminate strength is polyurethane / urea resin alone It was confirmed that it was improved compared to. (Meth) acrylic acid resin is excellent in adhesiveness but hard and brittle. Therefore, barrier properties are reduced by printing, and the laminate strength is low. It was likewise confirmed that a durable high strength laminate could be obtained. The above results show that a protective layer having various performances required for the protective layer can be formed by combining these two types of resins.

The coating liquid of this invention is used for formation of the protective layer of the vapor deposition thin film of a vapor deposition film. The film formed by applying the coating liquid of the present invention has excellent adhesion to the deposited thin film, has resistance to the solvent of printing ink, has excellent ink transferability, and avoids leveling problems after ink transfer. There is no decrease in barrier properties due to printing.

Claims (5)

  Poly (meth) acrylic acid or (meth) acrylic acid / (meth) acrylic acid ester copolymer containing 10% by mass or more of (meth) acrylic acid and polyurethane / urea resin having an ether bond as a film forming component A coating liquid characterized by containing.   The coating liquid according to claim 1 containing a crosslinking agent.   The coating liquid according to claim 2, wherein the crosslinking agent is a bifunctional or higher functional epoxy resin, polyisocyanate, or block polyisocyanate.   The coating solution according to claim 1 or 2, comprising a silane coupling agent. The vapor deposition film characterized by having the protective layer formed from the coating liquid of any one of Claims 1-4 in the metal oxide vapor deposition film surface of a vapor deposition film.