JP2021121498A - Front printing laminate for flexible packaging and flexible packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging bag for a flexible packaging surface-printed laminate which does not block even if an excessive winding pressure is applied when winding the laminated body in the manufacturing process of the flexible packaging surface-printed laminate. In this case, it is an object of the present invention to provide a flexible packaging surface printing laminate in which the appearance deterioration of the pattern due to rubbing between the packaging bags is improved.
SOLUTION:
It has a base material layer in which two or more base materials are laminated and a printing layer laminated on one side of the base material layer, and the printing layer contains a binder resin and a hydrocarbon wax having a melting point of 50 ° C. or higher. However, the substrate layer is characterized in that the wetness index of the surface in contact with the print layer is larger than the wetness index of the surface not in contact with the print layer, and the difference is 3 yne / cm or more. body.
[Selection diagram] Fig. 1

Description

The present invention relates to a front printing laminate for flexible packaging and a flexible packaging bag.

When a film substrate such as an OPP film, PET film, NY film, or metal-deposited film is used as a packaging material, printing with a printing ink is usually performed to decorate the substrate or protect the surface. The printed base material is then sent to a laminating process through a slitting process, and finally becomes a flexible packaging for food packaging, cosmetic packaging, and all other uses.

Such a flexible packaging package is composed of a laminate in which a film base material, a printing layer, and an adhesive layer are arbitrarily combined and laminated (laminated) as needed, in which the printing layer constitutes a pattern. Laminates for flexible packaging are roughly classified into two types, those having a back print layer and those having a front print layer. The laminate having the back print printing layer has a laminated structure in which the printing layer is sandwiched between the film substrates, and the pattern can be confirmed through the transparent substrate. On the other hand, in a laminate having a front print layer, the print layer is the outermost layer of the laminate. Since each of these has a different texture when the pattern is viewed, there are separate requests.

In a method for manufacturing a laminate having a front print layer, a laminate that has been prepared in advance is often used as an object to be printed. Compared to printing on a single-layer plastic base material, it is difficult to print the laminate neatly unless it is printed with a strong tension (called printing tension), so the internal pressure of the wound material rises and the printing layer Is required to have high blocking resistance.
After that, the front-print laminate is cut to the size of the package, and the edges are heat-sealed (called a heat-sealing process) to form a packaging bag. Since the corners of the bag to which the laminate is heat-sealed are hard and chewy, they may rub against the print layer of another front print laminate and cause a poor appearance of the print layer.

For example, Patent Document 1 shows a surface printing laminate having a polyurethane resin as a printing layer, and a printing layer having a fatty acid amide has been proposed for the purpose of improving blocking resistance. However, since fatty acid amide can be an element that permeates into a base material and causes adhesion inhibition, it is still difficult to obtain a flexible packaging surface-printed laminate having a good appearance.

Further, Patent Document 2 describes an invention relating to a laminate for molding processing having a front print layer, and proposes coating with a resin film to protect the print layer. In this way, the front print layer is easily scratched and it is required to improve the resistance to rubbing. Among them, the laminate for flexible packaging is bent, wrinkled, bent, etc. on the printed surface. It was difficult to achieve because of the large load.

Japanese Unexamined Patent Publication No. 2003-136652 Japanese Unexamined Patent Publication No. 7-3330019

INDUSTRIAL APPLICABILITY According to the present invention, when a flexible packaging front-print laminate that does not block even if an excessive winding pressure is applied during winding of the laminate in the manufacturing process of the flexible packaging front-print laminate is used as a packaging bag. An object of the present invention is to provide a front-printing laminate for flexible packaging in which poor appearance of a pattern due to rubbing between packaging bags is improved.

As a result of diligent research on the above problems, the present inventor has found that the problem can be solved by using the flexible packaging surface printing laminate described below, and has completed the present invention.

That is, the present invention is a front printing laminate for flexible packaging having a base material layer and a printing layer laminated on one side of the base material layer.
The printing layer contains a binder resin and a hydrocarbon wax having a melting point of 50 ° C. or higher, and the base material layer has a base material 1 constituting a surface in contact with the printing layer and a back surface not in contact with the printing layer. Containing the constituent base material 2,
The present invention relates to a front printing laminate for flexible packaging in which the wetting index of the surface of the base material layer in contact with the printing layer is larger than the wetting index of the back surface not in contact with the printing layer, and the difference between the wetting indexes is 3 dyn / cm or more.

Further, the present invention relates to the flexible packaging front printing laminate, wherein the binder resin contains a polyurethane resin and / or a polyamide resin in a total amount of 30% by mass or more in the total weight of the binder resin.

Further, in the present invention, the flexible packaging comprises a polyurethane resin or a polyamide resin and a cellulosic resin and / or a vinyl chloride-vinyl acetate copolymer resin in a mass ratio of 30/70 to 95/5. Regarding the surface printing laminate.
Further, the present invention relates to the above-mentioned surface printing laminate for flexible packaging in which the degree of needle insertion of the hydrocarbon wax is 0.1 to 15.
Further, the present invention relates to the flexible packaging front printing laminate, wherein the hydrocarbon wax contains a polyethylene wax.
Further, in the present invention, the base material layer has the base material 1, the adhesive layer and the base material 2 in this order, and the wettability index of the surface in contact with the printing layer is 30 to 60 dyn / cm. Regarding the laminate.

Further, the present invention relates to a flexible packaging bag made of the front-printed laminate for flexible packaging.

According to the present invention, when the flexible packaging surface printing laminate that does not block even if an excessive winding pressure is applied during winding of the laminated body is used as a packaging bag in the manufacturing process of the flexible packaging surface printing laminate. It has become possible to provide a front-printing laminate for flexible packaging in which the appearance deterioration of a pattern due to rubbing between packaging bags is improved.

It is a schematic cross-sectional view which showed an example of the structure of the front printing laminate for flexible packaging of this invention.

Hereinafter, embodiments of the present invention will be described in detail, but the description of the constituent elements described below is an example (representative example) of the embodiments of the present invention, and the present invention is described as long as the gist of the present invention is not exceeded. Not limited to the content.

The present invention has a base material layer in which two or more base materials are laminated, and a printing layer in which two or more base materials are laminated on one side of the base material layer.
The printing layer contains a binder resin and a hydrocarbon wax having a melting point of 50 ° C. or higher.
The base material layer is a surface printing laminate for flexible packaging, characterized in that the wettability index of the surface in contact with the printing layer is larger than the wetting index of the surface not in contact with the printing layer, and the difference is 3 dyn / cm or more. be.

<Print layer>
The print layer is a layer that constitutes a pattern. The print layer may be a print layer in which multiple colors are printed on top of each other, or only one color may be printed. The film thickness is preferably 1 to 10 μm. Further, the print layer is preferably a print layer obtained from gravure ink or flexo ink because the appearance is good. The printing layer contains a binder resin and a hydrocarbon wax having a melting point of 50 ° C. or higher. The mass ratio of the binder resin to the hydrocarbon wax is preferably 99: 1 to 90:10.

<Binder resin>
In the present invention, the binder resin refers to a thermoplastic resin soluble in an organic solvent, and preferably contains a total of 30% by mass or more of a polyurethane resin and / or a polyamide resin. Other binder resins include, for example, cellulose-based resin, vinyl chloride-vinyl acetate copolymer resin, acrylic resin, polyester resin, rosin-based resin, rosin-modified maleic acid-based resin, polystyrene-based resin, styrene-acrylic resin, and styrene-malein. Examples thereof include acid-based resins and modified resins thereof. You may use several kinds of these together. As the other binder resin, a cellulosic resin and / or a vinyl chloride-vinyl acetate copolymer resin is preferable.

The polyurethane resin or polyamide resin preferably has a glass transition temperature of −70 to 70 ° C. Here, the glass transition temperature refers to the temperature at the peak of the temperature-Tanδ value curve in the dynamic viscoelasticity measurement. The dynamic viscoelasticity measurement can be performed using, for example, DDV01-GP manufactured by A & D Co., Ltd. The measuring method may be a tensile type measuring method or a shearing type measuring method.

The binder resin preferably has a weight average molecular weight of 2000 to 100,000. The weight average molecular weight is a value measured by gel permeation chromatography (GPC).

The binder resin preferably contains a polyurethane resin and / or a polyamide resin in a total amount of 30% by mass or more, and more preferably 40% by mass or more. Further, it is preferable to contain a cellulose resin and / or a vinyl chloride-vinyl acetate copolymer resin, and 30/70 of the polyurethane resin or the polyamide resin and the cellulose resin and / or the vinyl chloride-vinyl acetate copolymer resin. It is preferably contained in a mass ratio of ~ 95/5, more preferably 40/60 to 95/5. It is preferable that these are contained in the binder resin in an amount of 70% by mass or more in total.

<Polyurethane resin>
The polyurethane resin is preferably a polyurethane resin composed of, for example, a polyol and a polyisocyanate. These have a structural unit composed of a urethane bond and a polyol and a structural unit composed of a polyisocyanate. Further, the chain may be further extended by a urea bond with an amine compound such as diamine or triamine. From the viewpoint of adhesiveness to the base material layer, the polyurethane resin preferably has a hydroxyl group and / or an amino group. The hydroxyl value is preferably 1 to 30 mgKOH / g, more preferably 1 to 20 mgKOH / g. The amine value is preferably 1 to 30 mgKOH / g, more preferably 1 to 20 mgKOH / g. The hydroxyl value is a value obtained by JISK0070 (1992), and the amine value is a value obtained by JISK1557-7 (2011). Further, the polyurethane resin preferably has a weight average molecular weight of 1000 to 100,000, more preferably 1000 to 70000. Further, the glass transition temperature is preferably −50 to 0 ° C.

Examples of the polyol include polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol and the like, and it is preferable to contain polyester polyol. The polyester polyol preferably has a structure composed of a condensate of sebacic acid or adipic acid and a diol. The diol preferably has 2 to 15 carbon atoms, and preferably contains a diol having a branched structure in which at least one hydrogen of the diol is substituted with an alkyl group. As the diol having a branched structure, for example, propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol and the like are preferable. These polyols preferably have a number average molecular weight of 200 to 3000.

Examples of the polyisocyanate include aliphatic polyisocyanates and aromatic polyisocyanates, and examples of the aliphatic polyisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate, which are aromatic. Examples of the diisocyanate include toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and the like, and the bonding position of the isocyanate group with the aromatic group may be any of the ortho-position, the meta-position, and the para-position.

In the production of the polyurethane resin, the reaction ratio (NCO / OH) of the isocyanate group of the polyisocyanate and the hydroxyl group of the polyol is preferably adjusted appropriately in the range of 0.8 to 2.5.

When an amine compound is used to carry out a chain extension reaction by a urea bond, it is preferable to use a diamine compound such as isophorone diamine, hexamethylenediamine, or methylenediamine.

The polyurethane resin is preferably produced in an organic solvent, and the organic solvent includes an aromatic organic solvent such as toluene, a ketone organic solvent such as methyl ethyl ketone, and an ester organic solvent such as ethyl acetate and n-propyl acetate. , Isopropanol, alcohol-based organic solvents such as ethanol, and mixed organic solvents thereof are preferable.

The polyurethane resin can be appropriately produced by a known production method. Examples of the production method include the methods described in JP-A-2017-0225256, JP-A-2017-039896, and the like.

<Polyamide resin>
The polyamide resin refers to a thermoplastic polyamide that is soluble in an organic solvent and can be obtained by polycondensing a polybasic acid and a polyvalent amine. In particular, it is preferably a polyamide resin containing an acid component containing a polymerized fatty acid and / or dimer acid and a reaction product of an aliphatic and / or aromatic polyamine, and further containing a part of primary and secondary monoamines. Is preferable.

The polybasic acid used as a raw material for a polyamide resin is not limited to the following, but is not limited to adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, and pimerin. Acids, oxalic acids, malonic acids, succinic acids, maleic acids, terephthalic acids, 1,4-cyclohexyldicarboxylic acids, trimellitic acids, dimer acids, hydrogenated dimer acids, polymerized fatty acids, among others, dimer acids, water Additive dimeric acid and polymerized fatty acid are preferable. Here, the polymerized fatty acid is obtained by a dry or semi-dry fat or oil fatty acid or an ester polymerization or transesterification reaction thereof, and includes a monobasic fatty acid, a dimerized polymerized fatty acid, a trimerized polymerized fatty acid and the like.
A monocarboxylic acid can also be used in combination with the polybasic acid. Examples of the monocarboxylic acid used in combination include acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, cyclohexanecarboxylic acid and the like.

Examples of the polyvalent amine include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine and methylaminopropylamine, and aliphatic polyamines such as diethylenetriamine and triethylenetetramine. Examples of the alicyclic polyamine include cyclohexylene. Examples thereof include diamine and isophorone diamine. Further, examples of the aromatic aliphatic polyamine include xylylenediamine, and examples of the aromatic polyamine include phenylenediamine and diaminodiphenylmethane.
Primary and secondary monoamines can be used in combination with the polyvalent amine. Examples of the primary and secondary monoamines include n-butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine.

The polyamide resin can be produced by a usual method for synthesizing a polyamide resin. The reaction temperature is 180 to 230 ° C., and the reaction is preferably carried out in an inert gas, and since it is a dehydration reaction, it is preferable to use a fractional distillation facility. Further, the reaction may be carried out under reduced pressure. The equivalent ratio of carboxyl group: amino group of the reaction component is preferably 0.9: 1.0 to 1.0: 0.9.

The polyamide resin preferably has a softening point of 80 to 140 ° C. and a weight average molecular weight of 2,000 to 70,000. When the softening point is 80 ° C. or higher, the surface tack breakage of the ink film of the printed matter becomes good, and blocking is prevented. When the softening point is 140 ° C. or lower, the ink film becomes flexible and the adhesiveness to the substrate is improved. When the weight average molecular weight range is 2,000 or more, the film strength of the ink is good, and the abrasion resistance, heat resistance, and high-speed printing suitability are improved. When the molecular weight is 70,000 or less, the viscosity of the ink can be lowered and the storage stability becomes good. The softening point represents a value measured by JIS K2207 (ring ball method).

<Vinyl chloride-vinyl acetate copolymer resin>
The vinyl chloride-vinyl acetate copolymer resin is a resin containing a copolymer of vinyl chloride and vinyl acetate as a main component. The weight average molecular weight is preferably 5000 to 100,000, more preferably 2000 to 70000. The content of the structural unit derived from the vinyl acetate monomer is preferably 1 to 30% by mass, and the content of the structural unit derived from the vinyl chloride monomer is 70 to 95% by mass in the solid content of the vinyl chloride-vinyl acetate copolymer resin. It is preferably%. In this case, the solubility in an organic solvent is improved, and the adhesion to the base material, the physical characteristics of the film, the lamination strength and the like are improved.
Further, in order to improve the solubility in an organic solvent, those containing a hydroxyl group derived from vinyl alcohol by saponification reaction or copolymerization are more preferable, and the hydroxyl value is preferably 20 to 200 mgKOH / g. The glass transition temperature is preferably 50 ° C to 90 ° C.

<Cellulose resin>
Examples of the cellulosic resin include nitrocellulose, cellulose acetate propionate, cellulose acetate butyrate, hydroxyalkyl cellulose, and carboxyalkyl cellulose. Examples of the alkyl group optionally contained in the cellulose resin include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group and the like. The alkyl group may have a substituent. Of these, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred. The weight average molecular weight is preferably 5000 to 100,000, more preferably 1000 to 20000. Further, the glass transition temperature is preferably 100 ° C. to 160 ° C.

(Nitrocellulose)
Nitrocellulose is a nitrate ester of cellulose, and natural cellulose is reacted with nitrate to obtain a nitrate ester in which 3 hydroxyl groups in the 6-membered ring of anhydrous glucopyranose group in natural cellulose are replaced with nitrate groups. The ones having an average degree of polymerization of 35 to 480, more preferably those in the range of 50 to 200 are preferable. When the average degree of polymerization is 50 or more, the strength of the ink film is improved, and the abrasion resistance and the rubbing resistance are improved, which is preferable. Further, when the average degree of polymerization is 200 or less, the solubility in a solvent, the low temperature stability of the ink, and the compatibility with the combined resin are improved, which is preferable. The nitrogen content is preferably 10.5 to 12.5% by mass.

<Hydrocarbon wax>
The printed layer contains a hydrocarbon wax having a melting point of 50 ° C. or higher. The melting point is preferably 70 ° C. or higher, and more preferably 90 to 130 ° C. In this case, the abrasion resistance and blocking resistance of the printed layer are improved, and the adhesion to the base material layer is also excellent.
Its content is preferably 0.1 to 17% by mass in the printed layer. It is more preferably 0.3 to 15% by mass, further preferably 0.5 to 12% by mass, and most preferably 0.8 to 12% by mass. In the gravure ink for forming the printing layer, it is preferable that the hydrocarbon-based wax is contained in an amount of 0.1 to 2.5% by mass in 100% by mass of the ink.

The melting point means a value measured by differential scanning calorimetry (DSC method).

By using a hydrocarbon-based wax in combination with a binder resin containing a polyurethane resin or a polyamide resin, even when the flexible packaging front printing laminate is used as a flexible packaging bag, when they rub against each other or overlap each other. It is possible to suppress scratches caused by the generated friction. It is considered that this is because when the hydrocarbon wax has the melting point, the affinity with the binder resin becomes good, and the printed layer becomes uniform and tough.

As the hydrocarbon wax, for example, polyethylene wax, polypropylene wax, Fishertroph wax, carnauba wax, paraffin wax, microstalin wax and the like are suitable, and two or more kinds may be used in combination. Among them, polyethylene wax and / or Fischer-Tropsch wax are preferable, and polyethylene wax is more preferable. As described above, these have a high affinity with polyurethane or polyamide resins, and are considered to have an effect of strengthening the printed layer.

The degree of needle insertion (hardness) of the hydrocarbon wax is ^{preferably 0.1 to 15 (unit: 10 -1} mm), and more preferably 0.5 to 15. Here, the degree of needle insertion means a value obtained by JIS K2207. Further, from the viewpoint of water resistance, the acid value is preferably 30 mgKOH / g or less.

Further, the printed layer preferably further contains a fatty acid amide. The fatty acid amide is preferably a saturated or unsaturated hydrocarbon having 8 to 25 carbon atoms, and for example, an oleic acid amide or a palmitic acid amide is preferable.

<Pigment>
The printing layer preferably contains a pigment. The mass ratio of the binder resin to the pigment (binder resin / pigment) is preferably 99/1 to 10/90. Further, it is more preferably 80/20 to 20/80. This is because the adhesiveness with the base material layer is good in the corresponding range.

As the pigment, either an organic pigment or an inorganic pigment can be used, and the inorganic pigment may be used in combination with the organic pigment. Further, an extender pigment such as barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate and silica may be contained. Organic pigments and inorganic pigments are preferable.

Organic pigments are not limited to the following examples, but are soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, anthanthrone-based, dianslaquinoni-based, anthrapyrimidine-based, perylene-based, Pigments such as perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethinazo, flavanthron, diketopyrrolopyrrole, isoindoline, indanslon, carbon black, etc. Be done. Also, for example, Carmin 6B, Lake Red C, Permanent Red 2B, Disazo Yellow, Pyrazolone Orange, Carmin FB, Chromophtal Yellow, Chromophtal Red, Phtalocyanin Blue, Phthalocyanin Green, Dioxazine Violet, Quinacridone Magenta, Kinacridone Red, Indance. Ron blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, carbon black, diketopyrrolopyrrole red, daylight fluorescent pigment, etc. are listed in the color index. Can be used at any time.

Inorganic pigments include zinc oxide, zinc sulfide, chromium oxide, aluminum particles, mica (mica), bronze powder, chromium vermilion, chrome yellow, cadmium yellow, cadmium red, ultramarine, dark blue, red iron oxide, yellow iron oxide, and iron black. Etc., and aluminum may be either a leafing type or a non-leaving type.

Titanium oxide is not particularly limited, but is preferably rutile-type, which is surface-treated with at least silica or alumina and has a crystal structure of rutile type. Further, it may be treated with other metals, and examples thereof include simple metals composed of elements of Si, Al, Zn and Zr, oxides of Al and Zn, and the like. The "treated" refers to a state in which the surface of the titanium oxide particles is coated.

The amount of oil absorbed by the measuring method specified in JIS K5101 is preferably 14 to 35 ml / 100 g, and more preferably 17 to 32 ml / 100 g. The average particle size (median particle size) measured by a transmission electron microscope is preferably 0.15 to 0.35 μm, more preferably 0.2 to 0.3 μm. The total content of the titanium oxide pigment is preferably 10 to 60% by weight, more preferably 10 to 45% by weight, based on 100% by weight of the ink. Further, a plurality of types of titanium oxide pigments may be used in combination. In addition to the titanium oxide pigment, other inorganic pigments and organic pigments can be further used in the gravure ink of the present invention.

<Other ingredients>
The printing layer may further contain an additive component. Examples of the additive include a pigment dispersant, a smoothing agent, a trapping agent, a defoaming agent, a chelating agent, a blocking agent, a lubricant, a viscosity modifier and the like.

<Base material layer> The base material layer is one in which two or more base materials are laminated so as to form the outermost surface of the base material layer, and the base material forming the outermost surface that comes into contact with the printing layer. An adhesive layer or another base material may be provided between 1 and the base material 2 that constitutes a surface that does not come into contact with the print layer.
The base material constituting the base material layer is preferably a film-like plastic base material, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polycarbonate and polylactic acid, polystyrene, AS resin, ABS resin and the like. Examples thereof include a film base material such as polystyrene resin, nylon, polyamide, polyvinyl chloride, polyvinylidene chloride, and cellophane, and a film base material made of a composite material thereof. The plastic base material may be vapor-deposited with a metal such as silica, alumina, or aluminum, or a metal oxide, and the vapor-deposited surface may be coated with a paint such as polyvinyl alcohol. Generally, the surface of the base material to be printed may be subjected to surface treatment such as corona treatment. Further, for these plastic substrates, it is possible to use a film obtained by processing a plastic film such as anti-fog agent coating, kneading, matting agent surface coating, and kneading in advance.

The antifogging agent is preferably a surfactant, for example, polyhydric alcohol fatty acid ester such as sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, glycerin fatty acid ester, and ionic surfactant such as ethylene oxide adduct. One or more agents may be used.

In the base material layer, the wetting index of the surface in contact with the printing layer (hereinafter abbreviated as the front surface) is larger than the wetting index of the surface not in contact with the printing layer (hereinafter abbreviated as the back surface). The difference is 3 dyn / cm or more, preferably 5 to 20 dyn / cm. The wetting index (wetting tension) refers to a value measured by the method described in JIS K 6768 using a wet index standard solution. When the difference in wettability index is within the above range, the adhesiveness between the front surface and the print layer is excellent, and blocking between the back surface and the print layer when the laminate is wound as the object to be printed in printing is suppressed. Can be done.

The surface of the base material layer is composed of the base material 1, and the wetting index of the surface is preferably 30 to 60 dyn / cm, more preferably 35 to 55 dyn / cm. The base material 1 is preferably a uniaxially or biaxially stretched plastic base material, and preferably has an easily adhesive surface that has been easily adhered so that the wetting index is within the above range. Examples of the easy-adhesion treatment include corona discharge treatment, ultraviolet / ozone treatment, plasma treatment, oxygen plasma treatment, primer treatment and the like. For example, in the corona discharge treatment, a hydroxyl group, a carboxyl group, a carbonyl group and the like are expressed on the substrate. Since hydrogen bonds can be used, the binder resin preferably has a functional group such as a hydroxyl group or an amino group.

The back surface of the base material layer is preferably composed of the base material 2, and the wettability index of the back surface is preferably 25 to 45 dyn / cm. The base material 2 is preferably a thermoplastic base material because the back surfaces of the front-print laminates are heat-sealed to form a flexible packaging bag. As the thermoplastic base material, unstretched polyethylene, unstretched polypropylene or other unstretched plastic base material is preferable.

<Adhesive layer>
The base material layer preferably has an adhesive layer between the base material 1 and the base material 2. Typical laminating methods include extrusion laminating, dry laminating, and non-solvent laminating, and further examples include a wet laminating method, a thermal laminating method, and a hot melt laminating method.
Examples of the adhesive layer include a layer made of an anchor coating agent, a urethane-based laminated adhesive, a molten resin, and the like, and these may be used in combination.
Anchor coating agents (AC agents) are preferably used in extrusion lamination, and examples of the AC agents include imine-based AC agents, isocyanate-based AC agents, polybutadiene-based AC agents, and titanium-based AC agents. Polyethylene is a typical molten resin, and those that melt at 280 to 360 ° C. can be appropriately used.
Examples of the urethane-based laminate adhesive include a polyether urethane-based laminate adhesive, a polyester urethane-based laminate adhesive, and the like, and examples thereof include a resin composed of a resin having a hydroxyl group and a resin having an isocyanate group. The one containing an organic solvent is a dry laminate adhesive, and the one without a solvent is a solvent-free laminate adhesive. It is preferable to use a polyester urethane-based laminated adhesive for flexible packaging applications that require a process such as retort.

<Table printing laminate for flexible packaging>
The front-printing laminate for flexible packaging of the present invention (hereinafter, may be abbreviated as a laminate) has a printing layer on one side of the base material layer.
As a method for producing the laminated body, a method in which a base material layer on which two or more base materials are laminated is first manufactured in advance and a printing layer is formed on the base material layer is preferable. Alternatively, a printed matter having a printing layer on the base material 1 may be prepared in advance and laminated with another base material containing the base material 2.
As a method of laminating the base material, for example, in the extrusion laminating, the base material 1 is coated with an anchor coating agent, and then a polyethylene resin heated and melted is hung from a thin slit called a T-die in a thin curtain shape to perform AC. It is placed on a layer, and the base material 2 is further pressure-bonded onto the molten polyethylene. These are performed in a series of operations. Examples of the manufacturing machine include a Co extrusion laminator manufactured by Musashinokikai.
In the dry laminate, an adhesive such as urethane is applied to the base material 1, dried, and a plastic film is laminated on the adhesive. Since the laminate adhesive is often a two-component type, it takes a certain period of time to cure, and it is preferable to cure it in about 24 to 48 hours.
The non-solvent laminating process is almost the same as the dry laminating process, but does not require a drying process because it does not contain a solvent. Examples of the machine for producing these dry laminates and non-solvent laminates include a dry laminator manufactured by Musashinokikai Co., Ltd. As for other laminating methods, it can be manufactured by a known method at any time.

<Flexible packaging bag>
The laminate that can be produced as described above is appropriately cut to the size of a food package (called a slit process). The cut laminate is combined into a bag shape, and the edge portion is heat-bonded (called a heat sealing process) to form a flexible packaging bag.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is merely an example of an embodiment of the invention, and the present invention is not limited to these examples. Unless otherwise specified, parts and% in the present invention represent parts by weight and% by weight.

(Hydroxy group value)
Obtained according to JIS K0070.
(Amine value)
Obtained according to JIS K1557-7: 2011.

(Weight average molecular weight)
The weight average molecular weight was determined by measuring the molecular weight distribution using a GPC (gel permeation chromatography) apparatus (HLC-8220 manufactured by Tosoh Corporation) and using polystyrene as a standard substance as a converted molecular weight. The measurement conditions are shown below.
Column: The following columns were connected in series and used.
TSKgel SuperAW2500 manufactured by Tosoh Corporation
TSKgel SuperAW3000 manufactured by Tosoh Corporation
TSKgel SuperAW4000 manufactured by Tosoh Corporation
TSKgel guardcolum SuperAWH manufactured by Tosoh Corporation
Detector: RI (Differential Refractometer)
Measurement conditions: Column temperature 40 ° C
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min

(Wetting index of base material)
It was determined according to the method described in JIS K 6768 using a wetness index standard solution.

(Glass-transition temperature)
It was determined by measuring with a dynamic viscoelasticity measuring machine (DDV01-GP manufactured by A & D Co., Ltd.) in a measurement temperature range of −70 to 250 ° C.

(Melting point)
It was determined by measuring by differential scanning calorimetry (DSC method) at a heating rate of 10 ° C./min in a measurement temperature range of 25 to 180 ° C. As the measuring machine, DSC-60Plus manufactured by Shimadzu Co., Ltd. was used.

[Preparation of base material layer] (Structure: base material 1 / adhesive layer / base material 2)
A polyester urethane-based laminated adhesive (TM250HV / CAT-RT86L-60 manufactured by Toyo Morton Co., Ltd.) was prepared as an ethyl acetate solution having a solid content of 20% in the following OPP, PET and alumina vapor-deposited PET, and the adhesive layer after drying was 2.0 g. After coating and drying so as to be / m ² , the CPP corresponding to the base material 2 is bonded to the adhesive layer and dry-laminated to perform the base material layers J (OPP), K (PET), L. (Alumina vapor-deposited PET) were obtained respectively. The difference in wettability index between the front surface and the back surface of the base material layer is J (5 dyn / cm), K (15 dyn / cm), and L (27 dyn / cm).
<Base material 1>
-OPP: Biaxially stretched polypropylene base material manufactured by Toyobo Co., Ltd. Product name P2261 Film thickness 20 μm Wetting index of the above surface 38 dyn / cm
-PET: Unitika Ltd. Biaxially stretched polyester base material Product name PTM Film thickness 12 μm Wetting index of the above surface 48 dyn / cm
-Alumina-deposited PET: Alumina-deposited biaxially stretched polyester base material manufactured by Mitsui Chemicals Tohcello Co., Ltd. Product name TL-PETHS The above-mentioned surface wettability index 60 dyn / cm
<Base material 2>
-CPP: Unstretched polypropylene base material manufactured by Toray Industries, Inc. Product name 9405S Film thickness 60 μm Wetting index 33 dyn / cm on the back surface described above

(Synthesis Example 1) [Polyurethane Resin PU1]
80 parts of polyester polyol with a number average molecular weight of 1000, 20 parts of polypropylene glycol with a number average molecular weight of 1000, 24.9 parts of dicyclohexylmethane-4,4'-diisocyanate, and 208 parts of ethyl acetate, which is a condensate of neopentyl glycol and adipic acid. Was reacted at 80 ° C. for 4 hours under a nitrogen stream. Further, the temperature was set to 40 ° C., and 208 parts of a mixed solvent of ethyl acetate: isopropanol (IPA) 1: 1 was added to adjust the solid content to 30% to obtain a polyurethane resin solution PU1. PU1 had an amine value of 0.0 mgKOH / g, a hydroxyl value of 4.5 mgKOH / g, a weight average molecular weight of 38,000, and a glass transition temperature of −15 ° C.

(Synthesis Example 2) [Polyurethane Resin PU2]
90 parts of polyester polyol having a number average molecular weight of 1000, 10 parts of polypropylene glycol having a number average molecular weight of 1000, 46.7 parts of isophorone diisocyanate, and 36.7 parts of ethyl acetate, which are a condensate of methylpentanediol and adipic acid. The reaction was carried out at 80 ° C. for 4 hours, and the reaction solution was cooled to 40 ° C. Next, 40 parts of the reaction solution was added to a mixed solution consisting of 13.7 parts of isophorone diamine, 5.0 parts of 2- (2-aminoethylamino) ethanol, and 328.4 parts of a mixed solvent of ethyl acetate: isopropanol 1: 1. The mixture was gradually added at ° C. and then reacted at 80 ° C. for 1 hour to obtain a polyurethane resin solution PU2. PU2 had a solid content of 30%, an amine value of 5.5 mgKOH / g, a hydroxyl value of 16.3 mgKOH / g, a weight average molecular weight of 55,000, and a glass transition temperature of −30 ° C.

(Manufacturing Example 1) [Manufacturing of Gravure Ink S1]
The mixture was mixed with the following composition and kneaded and dispersed in a sand mill for 20 minutes to obtain a gravure ink S1.
-Polyurethane resin solution PU2 (solid content 30%): 36 parts-Vinyl chloride-vinyl acetate copolymer resin solution (solvine TA3 solid content 30%): 4 parts In the table, it is abbreviated as "PVC resin solution".
・ Titanium oxide (CR-80 rutile type crystal structure manufactured by Ishihara Sangyo Co., Ltd., surface treatment with silica and alumina, average particle size 0.25 μm, oil absorption 20 (ml / 100 g)) 30 parts ・ Wax particles 1 (polyethylene (wax) particles) Needle penetration 13 Melting point 110 ° C): 0.2 parts ・ Mixed solvent (propyl acetate / IPA = 70/30) 29.8 parts

(Manufacturing Examples 2 to 15) [Manufacturing of gravure inks S2 to S15]
Gravure inks S2 to S15 were produced in the same manner as in Production Example 1 except that the raw materials shown below were used. Table 1 shows the ink composition. The abbreviations of the raw materials in Table 1 are as follows. -S-2800: Polyamide resin manufactured by Kao Corporation Softening point 115 ° C. Weight average molecular weight 3500 (solid content 30% IPA / toluene = 30/70 solution)
-Solvine TA3: Vinyl chloride-vinyl acetate copolymer resin manufactured by Nissin Chemical Co., Ltd. Vinyl chloride structure / vinyl acetate structure / hydroxy acrylic structure = 83/4/13 (ethyl acetate solution with a solid content of 30%)
DLX5-8: Nitrocellulose manufactured by ICI Novel enterprises
Nitrogen content 12.0% (solid content 30% isopropanol solution)
・ FG7400G: Pigment Blue 15: 4 made by Toyo Color Co., Ltd. ・ Phthalocyanine pigment ・ Wax particles 2: Polyethylene (wax) particles Needle penetration 7 Melting point 109 ℃
-Wax particles 3: Fischer-Tropsch (wax) particles Needle penetration 2 Melting point 102 ° C.-Wax particles 4: Paraffin (wax) particles Needle penetration 17 Melting point 53 ° C

(Comparative Production Examples 1 to 7) [Preparation of Gravure Inks T1 to T7]
With the raw materials and compounding compositions shown in Table 2, gravure inks T1 to T7 were obtained by the same method as described in Production Examples 1 to 15 above.
-Oleic acid amide: Fatty acid amide Melting point 70 ° C
-Wax particles 5: Paraffin (wax) particles Needle penetration 30 Melting point 47 ° C

(Example 1)
<Formation of surface printing laminate for flexible packaging> (Gravure printing on substrate layers J, K, L)
The gravure ink S1 obtained above is diluted with a mixed solvent (methyl ethyl ketone: N propyl acetate: isopropanol = 40: 40: 20) so that the viscosity becomes 16 seconds (25 ° C., Zahn cup No. 3). , Corrosion 175-line solid plate (plate type compressed, 100% solid pattern) is used to print on the surfaces of the base material layers J, K and L at a printing speed of 100 m / min. L1 was obtained respectively. The printing conditions were a temperature of 25 ° C. and a humidity of 60%.

(Examples 2 to 15)
Using the inks shown in Table 1, the flexible packaging front printing laminates J2 to J15, K2 to K15, and L2 to L15 were obtained in the same manner as in Example 1.

(Comparative Examples 1 to 7)
Using the inks shown in Table 2, the flexible packaging front printing laminates JJ1 to JJ7, KK1 to KK7, and LL1 to LL7 were obtained in the same manner as in Example 1.

<Evaluation>
The following evaluations were made on the laminated bodies of Examples and Comparative Examples. The results are shown in Tables 3 and 4.

<Blocking resistance>
The blocking resistance of the flexible packaging front print laminates J1 to J15, K1 to K15 and L1 to L15 and JJ1 to JJ7, KK1 to KK7 and LL1 to LL7 was evaluated under the following conditions.
(Sample and pressure)
A pressure of ^{6 kg / cm 2} was applied by superimposing the printing layer of the front printing laminate for various flexible packaging and the back surface of the above-mentioned CPP.
(Standing condition) 40 ° C-80% RH 48 hours (Evaluation method) The stacked laminates are peeled off, and the degree of peeling of the ink film from the printed surface is visually judged.
Judgment criteria 5. The print layer does not peel off at all and the peeling resistance is low (good)
4. The peeling area of the print layer is 1% or more and less than 5%, and the peeling resistance is small (practical)
3. 3. The peeled area of the print layer is 5% or more and less than 20% (slightly defective)
2. The peeled area of the print layer is 20% or more and less than 50% (defective)
1. 1. Print layer peels off by 50% or more (extremely defective)
Note that 5 and 4 are ranges in which there is no practical problem.

<Scratch resistance>
For the flexible packaging front print laminates J1 to J15, K1 to K15 and L1 to L15, and JJ1 to JJ7, KK1 to KK7 and LL1 to LL7, the surface of the print layer was rubbed three times with a nail to evaluate the degree of damage to the print layer. ..
Judgment criteria 5. No scratches on the print layer (good)
4. The print layer is not scratched, but a slight nail mark remains. (Practical)
3. 3. The print layer is scratched and the surface of the print layer is slightly scooped out. (Slightly bad)
2. The printed layer is scratched and the substrate is slightly visible. (Defective)
1. 1. The printed layer is scratched and the substrate is clearly visible. (Extremely bad)
Note that 5 and 4 are ranges in which there is no practical problem.

<Abrasion resistance>
The flexible packaging front print laminates K1 to K15 and KK1 to KK7 are cut into 20 mm x 250 mm pieces to make test pieces, and a Gakushin type friction resistance tester (manufactured by Daisung Kagaku Seiki Seisakusho Co., Ltd.) is used. , The abrasion resistance of the printed layer was evaluated under the following conditions.
Load: 200g (Kanakin No. 3) Number of frictions: 40 times Reciprocating temperature: 25 ° C
Judgment criteria 5. No peeling of print layer (good)
4. The peeled area of the print layer is less than 10% (practical)
3. 3. The peeled area of the print layer is 10% or more and less than 30% (slightly defective)
2. The peeled area of the print layer is 30% or more and less than 50% (defective)
1. 1. Full peeling (extremely defective)
Note that 5 and 4 are ranges in which there is no practical problem.

(Comparative Example 8)
[Preparation of base material layer] (Structure: base material 1 / adhesive layer / base material 2)
In the following OPP, a polyester urethane-based laminate adhesive (TM250HV / CAT-RT86L-60 manufactured by Toyo Morton Co., Ltd.) is used as an ethyl acetate solution having a solid content of 20%, and the adhesive layer after drying is 2.0 g / m ^2. After coating and drying, the CPP corresponding to the base material 2 was attached to the adhesive layer and dry-laminated to obtain a base material layer M (OPP).
<Base material 1>
-OPP: Biaxially stretched polypropylene base material manufactured by Futamura Chemical Co., Ltd. Product name FOA Film thickness 20 μm Wetting index of the above surface 28 dyn / cm
<Base material 2>
-CPP: Unstretched polypropylene base material manufactured by Toray Industries, Inc. Product name 9405S Film thickness 60 μm Wetting index 33 dyn / cm on the back surface described above
The gravure ink S4 prepared in Example 1 was printed on the surface of the base material layer M in the same manner as in Example 16 to obtain a front print laminate M1 for flexible packaging. The above-mentioned performance evaluation of the obtained laminate was blocking resistance: 2, scratch resistance: 3, and abrasion resistance: 3.

According to the present invention, when the flexible packaging surface printing laminate that does not block even if an excessive winding pressure is applied during winding of the laminated body is used as a packaging bag in the manufacturing process of the flexible packaging surface printing laminate. It has become possible to provide a front-printing laminate for flexible packaging in which poor appearance of a pattern due to rubbing between packaging bags is improved.

1 ... Printing layer 2 ... Base material 1
3 ... Adhesive layer 4 ... Base material 2

Claims (7)

A flexible packaging front printing laminate having a base material layer and a printing layer laminated on one side of the base material layer.
The printing layer contains a binder resin and a hydrocarbon wax having a melting point of 50 ° C. or higher, and the base material layer has a base material 1 constituting a surface in contact with the printing layer and a back surface not in contact with the printing layer. Containing the constituent base material 2,
A front printing laminate for flexible packaging in which the wetting index of the surface of the base material layer in contact with the printing layer is larger than the wetting index of the back surface not in contact with the printing layer, and the difference between the wetting indexes is 3 dyn / cm or more. The cover printing laminate for flexible packaging according to claim 1, wherein the binder resin contains a polyurethane resin and / or a polyamide resin in a total amount of 30% by mass or more in the total mass of the binder resin. The first or second claim, wherein the binder resin contains a polyurethane resin or a polyamide resin and a cellulosic resin and / or a vinyl chloride-vinyl acetate copolymer resin in a mass ratio of 30/70 to 95/5. Front printing laminate for flexible packaging. The front-print laminate for flexible packaging according to any one of claims 1 to 3, wherein the degree of needle insertion of the hydrocarbon wax is 0.1 to 15. The front-print laminate for flexible packaging according to any one of claims 1 to 4, wherein the hydrocarbon-based wax contains a polyethylene wax. The softness according to any one of claims 1 to 5, wherein the base material layer has the base material 1, the adhesive layer, and the base material 2 in this order, and the wettability index of the surface in contact with the printing layer is 30 to 60 dyn / cm. Front printing laminate for packaging. A flexible packaging bag made of the front-printed laminate for flexible packaging according to any one of claims 1 to 6.

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