KR102502893B1 - eco-friendly packaging film - Google Patents

Abstract

The present invention provides an eco-friendly packaging film which is eco-friendly and has excellent printability and durability. According to the present invention, the eco-friendly packaging film comprises: a first polymer film; an eco-friendly ink printing layer laminated on one surface of the first polymer film; an adhesive layer laminated on the other surface of the printed layer; and a second polymer film laminated on the other surface of the adhesive layer. The eco-friendly ink contains 10 to 35 wt% of polyurethane resin, 10 to 35 wt% of pigment, 5 to 10 wt% of vinyl butyral polymer, 0.5 to 5 wt% of emulsifying wax, 0.5 to 5 wt% of and coco-betaine, and 30 to 60 wt% of ethanol solvent.

Description

Eco-friendly packaging film {eco-friendly packaging film}

The present invention relates to an eco-friendly packaging film, and more particularly, to an eco-friendly packaging film that does not contain harmful substances to the human body such as volatile organic compounds (VOCs) and formaldehyde.

Various packaging materials (including packaging films) including food and household items in the prior art contain volatile organic compounds (VOC), including Toluene, MKE, EA, MeOH, and IPA, which are regulated volatile organic compounds (VOC). It was produced through a gravure printing process using ink used as a diluting solvent.

As the gravure ink used for the gravure printing, oil-based ink containing base resin, pigment, wax, filler, and solvent has been conventionally used. However, such oil ink contains harmful chemical components such as benzene, toluene, xylene, methyl ethyl ketone, methylene chloride, chloroform, etc., which are regulated substances of volatile organic compounds (VOC), as solvents. These organic solvents, as well as odor, have a harmful effect on the human body or the environment by themselves, causing problems such as environmental pollution and deterioration in safety and hygiene of workers.

More specifically, these organic solvents are released into the air during the ink drying process, become air pollutants, are directly exposed to workers and are harmful to the human body, and pose a risk of fire during printing. In addition, if these organic solvents remain on printed materials, hygienic printed materials cannot be obtained, and in particular, when food wrapping paper is printed using such an oil-based ink, the organic solvent remaining on the wrapping paper may have a harmful effect on the final consumer. There was a possible problem. In addition, organic solvents with low boiling points evaporate during the printing process, which easily changes the viscosity of the ink and deteriorates printability. And standards such as the wearing of protective equipment by workers are strengthened, resulting in many restrictions in storage, management and handling.

On the other hand, the use of an aqueous gravure ink that does not use an organic solvent as described above has been considered, but there is a problem in that productivity decreases due to an increase in the time required to dry the printed matter, and consequently, problems such as deterioration in the quality of printed matter occur Therefore, it was difficult to apply in the actual field.

Therefore, there is a demand for the development of a packaging film using eco-friendly ink, which is environmentally friendly because it does not use organic solvents that have a harmful effect on the human body and the atmosphere, and has excellent workability and print quality.

Republic of Korea Patent No. 10-2136002

The present invention has been made to solve the problems of the prior art described above,

It is an object of the present invention to provide an eco-friendly packaging film that is environmentally friendly because it hardly generates harmful substances such as volatile organic compounds (VOCs) and formaldehyde, and has excellent printability and durability.

In order to achieve the above object, the present invention

A first polymer film, an eco-friendly ink printing layer laminated on one surface of the first polymer film, an adhesive layer laminated on the other surface of the printed layer, and a second polymer film laminated on the other surface of the adhesive layer,

The eco-friendly ink contains 10 to 35% by weight of polyurethane resin, 10 to 35% by weight of pigment, 5 to 10% by weight of vinyl butyral polymer, 0.5 to 5% by weight of emulsifying wax, coco An eco-friendly packaging film containing 0.5 to 5% by weight of betaine and 30 to 60% by weight of an ethanol solvent is provided.

The eco-friendly packaging film according to the present invention is eco-friendly because it hardly generates harmful substances such as volatile organic compounds (VOCs) and formaldehyde, and provides excellent printability and durability.

1 is a cross-sectional view schematically showing a cross-section of an eco-friendly packaging film as an embodiment of the present invention.
2 is a view showing measurement conditions in Test Example 3 regarding the measurement of harmful gas emissions for an eco-friendly ink composition.

Hereinafter, the present invention will be described in detail.

As shown in FIG. 1, the eco-friendly packaging film 100 of the present invention includes a first polymer film 10, an eco-friendly ink printing layer 20 laminated on one side of the first polymer film, and a layer on the other side of the printing layer. It includes a laminated adhesive layer 30, and a second polymer film 40 laminated on the other side of the adhesive layer,

The eco-friendly ink contains 10 to 35% by weight of polyurethane resin, 10 to 35% by weight of pigment, 5 to 10% by weight of vinyl butyral polymer, 0.5 to 5% by weight of emulsifying wax, coco It is characterized by including 0.5 to 5% by weight of betaine and 30 to 60% by weight of an ethanol solvent.

The first polymer film is not particularly limited, but, for example, an oriented polypropylene (OPP) film or a polyethylene terephthalate (PET) film may be used.

The second polymer film is not particularly limited, but, for example, a non-stretched film (CPP), an aluminum deposited non-stretched film (VM-CPP), or a linear low density polyethylene (LLDPE) film may be used. .

Hereinafter, the eco-friendly ink used in the present invention will be described in detail.

As the polyurethane resin, a polyurethane resin known in the art may be purchased and used, and in particular, it is more preferable to use a polyurethane resin having the following characteristics.

That is, the polyurethane resin is a urethane prepolymer manufacturing step of preparing a urethane prepolymer by reacting a polyol and a diisocyanate compound; A dilution step of mixing the urethane prepolymer with an ethanol solvent; and a polyurethane resin production step of preparing a polyurethane resin by reacting the urethane prepolymer that has undergone the dilution step with an amine-based chain extender.

The urethane prepolymer preparation step may be performed by mixing a polyol and a diisocyanate compound in an equivalent ratio of 1: 1 to 3 and reacting at 60 to 90 ° C. for 2 to 5 hours. At this time, in order to improve the reactivity, a catalyst such as dibutyltin dilaurate may be mixed and reacted together.

The polyol is a general one used in the field, and the type is not particularly limited, but considering the printability of the ink and the adhesion to the substrate, a polyether polyol containing an ether linkage having a number average molecular weight of 1000 to 3000 is selected. It can be used more preferably. Non-limiting examples of such polyether polyols include polytetramethyl ether glycol (PTMG), polyethylene glycol (PEG), polypropylene glycol (PPG), 1,2-butanediol ( 1,2-Butandiol) and at least one selected from the group consisting of mixtures thereof. More preferably, polytetramethyl ether glycol may be used alone or polytetramethyl ether glycol and 1,2-butanediol may be used together.

The diisocyanate compound is a general one used in the art, and the type is not particularly limited, but non-limiting examples include hexamethylene diisocyanate, isophorone diisocyanate, 2,4 - At least one selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and mixtures thereof may be used. More preferably, a mixture of hexamethylene diisocyanate and isophorone diisocyanate at a weight ratio of 1:0.5 to 1 may be used.

The amine-based chain extender is a general one used in the art, and the type is not particularly limited, but non-limiting examples include ethylene diamine, propylene diamine, and hexamethylene diamine. ), isophorone diamine, dicyclohexylmethane 4,4-diamine, diethylene triamine, triethylene teramine and mixtures thereof. One or more types selected from the group consisting of can be used. More preferably, ethylene diamine may be used.

The polyurethane resin is preferably contained in the range of 10 to 35% by weight based on the eco-friendly ink. When the content of the polyurethane resin is less than 10% by weight, the above-described improvement effect may be insufficient, and when the content of the polyurethane resin exceeds 35% by weight, the color of the ink becomes blurred and the color development or printability is deteriorated. It can be.

The pigment is added to impart color, and is not limited to organic pigments or inorganic pigments. The pigment is preferably contained in the range of 10 to 35% by weight based on the eco-friendly ink. If the content of the pigment is less than 10% by weight, the above-mentioned improvement effect may be insufficient, and if the content of the pigment exceeds 35% by weight, the viscosity of the ink increases, the dispersibility of the pigment decreases, and the aggregation and sedimentation of the pigment problems may occur.

The pigments include carbon black, monoazo pigments, diazo pigments, azo lake pigments, phthalocyanine pigments, perylene pigments, perinone pigments, polyazo pigments, quinatridone pigments, natural aqueous derived from indigo (Persicaria tincroria) Pigment, natural aqueous pigment derived from red wood, natural aqueous pigment derived from tumeric, natural aqueous pigment derived from clove, natural aqueous pigment derived from gallnut, natural aqueous pigment derived from rubis tinctoria root, At least one pigment selected from the group consisting of a natural aqueous pigment derived from Phellodendron amurense, a natural aqueous pigment derived from Solindago virgaurea, and a natural aqueous pigment derived from walnut (Juglans regia) may be used.

The vinyl butyral resin (vinyl butyral polymer) has excellent miscibility with the polyurethane resin and performs a function of well dispersing the pigment. When the vinyl butyral resin is included in an amount exceeding 5 to 10% by weight, it is not preferable because the quality of the ink is deteriorated.

The emulsifying wax functions to increase releasability by improving the solidification speed after the eco-friendly ink is transferred to the base film. The emulsifying wax may be pulverized into fine powder or used in a pre-dissolved state in a solvent.

The emulsifying wax is preferably contained in the range of 0.1 to 5% by weight. If the content of the emulsifying wax is too small, the improvement effect may be insufficient, and if the content is too large, excellent adhesion and dispersibility to the substrate may be deteriorated.

The coco betaine (Coco-betaine) performs a function of improving the dispersibility of the pigment as a surfactant. The coco betaine is an amphoteric surfactant obtained from coconut oil, and since it has both negative and positive charges, it functions to improve the dispersibility of the pigment. The coco betaine may be purchased and used commercially regardless of the type.

The coco betaine is included in an amount of 0.1 to 5% by weight, and when included in a range outside this range, it is difficult to expect an effect of improving the dispersibility of the pigment.

In one embodiment of the present invention, the eco-friendly ink may further include 5 to 10% by weight of a copolymer represented by Formula 1 below.

[Formula 1]

In the above formula, a, b and c represent mole fractions,

Wherein a is 0.1 to 0.4, b is 0.1 to 0.4, c is 0.3 to 0.7, and a+b+c is 1.

In the present invention, the copolymer represented by Chemical Formula 1 strengthens the adhesive strength of the eco-friendly ink and performs a function of allowing the pigment to be fixed in a well-dispersed state.

[Formula 1]

In the above formula, a, b and c represent mole fractions,

Wherein a is 0.1 to 0.4, b is 0.1 to 0.4, c is 0.3 to 0.7, and a+b+c is 1.

The 2-octylcyanoacrylate monomer-derived unit included in the copolymer of Chemical Formula 1 is a monomer that provides excellent adhesion to organic and inorganic materials. In addition, methacryloxypropyl tris (trimethylsiloxy) silane (METHACRYLOXYPROPYLTRIS (TRIMETHYLSILOXY) SILANE, CAS No: 17096-07-0) monomer derived unit forms a very good bond with organic and inorganic materials. In addition, the derived unit of the t-butyl acrylate monomer also forms an excellent bond with organic and inorganic materials.

The copolymer of Chemical Formula 1 allows the pigment to be well dispersed in the ink composition, improves the strength of the printed film, and enables the environmentally friendly ink to form a strong bond with the first polymer film.

The copolymer of Chemical Formula 1 is a random copolymer, and may have a weight average molecular weight of 50,000 to 500,000, more preferably 150,000 to 300,000.

The eco-friendly ink composition may further include a dispersant known in the art. The dispersant can provide excellent printability, fast drying speed, and excellent adhesion to a substrate by improving the dispersibility of the eco-friendly ink.

In addition, the eco-friendly ink composition may further include a curing agent known in the art, the curing agent may be an isocyanate-based or epoxy-based curing agent, and as other curing agents, Ethacure-300 (Dimethyl-thiotoluene diamine), HQEE (Hydroquinone bis (2-hydroxyethyl) ether) and the like may be used.

The adhesive layer may be formed of an environmentally friendly adhesive composition containing 60 to 80% by weight of polyurethane resin and 20 to 40% by weight of ethanol.

In addition, the adhesive layer may be formed of an environmentally friendly adhesive composition containing 50 to 70% by weight of a polyurethane resin, 20 to 40% by weight of ethanol, and 5 to 10% by weight of a copolymer represented by Formula 1 below.

[Formula 1]

In the above formula, a, b and c represent mole fractions,

Wherein a is 0.1 to 0.4, b is 0.1 to 0.4, c is 0.3 to 0.7, and a+b+c is 1.

An adhesive composition further containing the copolymer represented by Formula 1 is preferable because adhesive strength is greatly improved and a strong bond can be formed in a small amount.

Hereinafter, the present invention will be described in detail through preferred embodiments. However, this only has the purpose of clarifying the practice of the invention to those skilled in the art, and does not mean that the scope of the present invention is limited by these examples.

Preparation Example 1: Preparation of polyurethane resin

A polyol (polytetramethyl ether glycol) and a diisocyanate compound (isophorone diisocyanate) were mixed in an equivalent ratio of 1:3 and reacted at 65° C. for 5 hours to prepare a urethane prepolymer. The prepared urethane prepolymer and ethanol were mixed at a weight ratio of 1:1.5 to dilute the urethane prepolymer. Thereafter, 100 parts by weight of the diluted urethane prepolymer was mixed with 3.5 parts by weight of an amine-based chain extender (ethylene diamine) and 1.5 parts by weight of N-2-(aminoethyl)-3-aminopropyl trimethoxysilane at 45 ° C. A polyurethane resin was prepared by reacting for 4 hours.

Preparation Example 2-1: Preparation of eco-friendly adhesive composition

An eco-friendly adhesive composition was prepared by mixing 75% by weight of the polyurethane resin prepared in Preparation Example 1 and 25% by weight of ethanol.

Preparation Example 2-2: Preparation of eco-friendly adhesive composition

An eco-friendly adhesive composition was prepared by mixing 70% by weight of the polyurethane resin prepared in Preparation Example 1, 25% by weight of ethanol, and 5% by weight of the copolymer of Chemical Formula 1 prepared in Preparation Example 3 below.

Preparation Example 3: Preparation of the copolymer of Formula 1

2-octylcyanoacrylate, methacryloxypropyltris(trimethylsiloxy)silane (METHACRYLOXYPROPYLTRIS(TRIMETHYLSILOXY)SILANE, CAS No: 17096-07-0) and t-butyl acrylate were mixed with ethylbenzene as a reaction solvent in a ratio of 0.2:0.5 : 0.3, and 0.5 parts by weight of normal mercaptan was mixed with 100 parts by weight of all monomers to make it uniform.

The polymerization solution prepared above was introduced into a 20 L reactor at a rate of 10 L/hr and polymerized at a temperature of 100 ° C., and unreacted monomers and reaction solvents were removed in a volatilization tank at a temperature of 150 ° C., followed by washing, dehydration and drying. A copolymer of Formula 1 having a weight average molecular weight of 245,000 was obtained.

[Formula 1]

In the above formula, a, b and c represent mole fractions,

The a is 0.2, b is 0.3, and c is 0.5.

Example 1: Preparation of eco-friendly ink composition

Polyurethane resin prepared in Preparation Example 1 25% by weight, pigment 25% by weight, vinyl butyral resin 8% by weight, emulsifying wax 3% by weight, coco betaine 3% by weight , and 36% by weight of ethanol were mixed to prepare an eco-friendly ink composition.

Example 2: Preparation of eco-friendly ink composition

Polyurethane resin prepared in Preparation Example 1 25% by weight, pigment 25% by weight, vinyl butyral resin 7% by weight, emulsifying wax 2% by weight, coco betaine 2% by weight , An eco-friendly ink composition was prepared by mixing 7% by weight of the copolymer represented by Formula 1 prepared in Preparation Example 3 and 32% by weight of ethanol.

Comparative Example 1: Gravure Ink

A commercially available "gravure eco ink" (manufactured by YOULSAN) was purchased and used as Comparative Preparation Example 1.

Example 3: Manufacturing of eco-friendly packaging film

Using the eco-friendly ink composition prepared in Example 1, a gravure printing process (line 225, depth 13 μm) was performed on the OPP film. At this time, the gravure printing has a drying chamber temperature of 85 ° C or higher, an anodized spiral groove cooling roller is used as a cooling roller, the cooling water temperature is 19 ° C, and the angle between the printed copper plate and the doctor blade was 63°, the cell wall height of each color printed copper plate was 10 μm, and the air volume supplied to the drying box was 63 CMM.

The eco-friendly adhesive prepared in Preparation Example 2-1 was applied on the printed layer formed by the above process, dried and cured at 60 ° C, and a CPP film was laminated thereto to prepare an eco-friendly packaging film of the present invention.

Example 4: Manufacturing of eco-friendly packaging film

An eco-friendly packaging film of the present invention was manufactured in the same manner as in Example 3, except that the eco-friendly adhesive prepared in Preparation Example 2-2 was used instead of the eco-friendly adhesive prepared in Preparation Example 2-1 in Example 3.

Example 5: Manufacturing of eco-friendly packaging film

An eco-friendly packaging film of the present invention was prepared in the same manner as in Example 3, except that the eco-friendly ink composition prepared in Example 2 was used instead of the eco-friendly ink composition prepared in Example 1 in Example 3.

Example 6: Manufacturing of eco-friendly packaging film

An eco-friendly packaging film of the present invention was manufactured in the same manner as in Example 3, except that the eco-friendly adhesive prepared in Preparation Example 2-2 was used instead of the eco-friendly adhesive prepared in Preparation Example 2-1 in Example 5.

Comparative Example 2: Preparation of packaging film

An eco-friendly packaging film of the present invention was prepared in the same manner as in Example 3, except that the gravure ink of Comparative Example 1 was used instead of the eco-friendly ink composition prepared in Example 1 in Example 3.

Test Example 1: Evaluation of adhesion of printed layer

For the OPP films in which the gravure printing process was completed during the packaging film manufacturing process of Examples 3 to 6 and Comparative Example 2, the adhesion of the printed layer was evaluated by applying the ASTM D 2259 standard, and the average value of the results of repeating this three times (Only indicated up to one decimal place) is shown in Table 1 below. At this time, the ASTM D 2259 standard is the degree of ink layer (cured ink) separated from the substrate (film) when the adhesive tape is attached to the substrate (film), pressed with the same force, and then the adhesive tape is slowly peeled off. is identified, and evaluated by dividing it into 1B ~ 5B. At this time, 5B is 0% of the separated ink layer (best), 4B is less than 5% of the separated ink layer, 3B is 5 to 15% of the separated ink layer, 2B is 15 to 35% of the separated ink layer, and 1B is separated 35 to 65% of the separated ink layer, 0B means more than 65% of the separated ink layer (worst).

packaging film printing layer Example 3
(Using the ink prepared in Example 1) Example 5
(Using ink prepared in Example 2) Comparative Example 2
(Use commercially available ink) Adhesion evaluation result 4.4B 4.9B
3.8B

Test Example 2: Evaluation of tensile strength of eco-friendly packaging film

The T-type peel strength of the packaging films of Examples 3 to 6 and Comparative Example 2 was measured at a speed of 300 mm/min using a universal tester, and the results are shown in Table 2 below.

Example 3 Example 4 Example 5 Example 6 Comparative Example 2 Print film strength
(g/mm) 240 247 246 260 235

Test Example 3: Measurement of harmful gas emissions (TVOC and formaldehyde) for eco-friendly ink composition

The emissions of volatile organic compounds (hereinafter, VOCs) and formaldehyde (hereinafter, HCHO) emitted from eco-friendly ink compositions were measured using the small chamber method presented in the indoor air quality process test method. The test was conducted in a small chamber where the temperature, relative humidity, and ventilation per unit area were kept constant. The air inside the small chamber was thoroughly mixed, and the concentrations of VOCs and HCHO were measured in the air collected from the outlet side. The emission per unit area was calculated.

If the air concentration inside the chamber and the blank concentration are known, the amount of emission per unit area of VOCs and HCHO at a specific time can be measured in the eco-friendly ink composition under test by identifying the air flow flowing through the small chamber and the surface area of the test piece.

<Analysis method and analysis conditions>

According to the pollutant emission test of building materials, two specimens were fixed with a specimen fixing frame (actual exposed surface area 140 mm × 140 mm) and installed in the center of a small chamber. The number of ventilations was adjusted to 0.5 times per hour while flowing pure air at 167 mL/min into the small chamber so that the sample could be exposed to an atmosphere of 27°C and 60% relative humidity. Samples were collected after maintaining the small chamber under the same conditions for 7 days. In the case of VOCs, a total of 3.2 L of samples were collected at a flow rate of 167 mL/min using an adsorption tube filled with Tenax TA, and 10 L of formaldehyde was collected using a DNPH cartridge. The collected samples were immediately analyzed by TD-GC/MS (VOCs) and HPLC (formaldehyde).

The maintenance conditions of the small chamber, the sampling conditions, and the analysis conditions of each analysis equipment are shown in FIG. 2, and the experimental results are shown in Table 1 below.

matter Emission (mg/m ² h) Example 1 Example 2 Comparative Example 1 TVOC 0.011 0.011 0.5 Benzene 0.001 0.001 almost undetectable Toluene 0.001 0.001 0.001 Xylene almost undetectable almost undetectable almost undetectable Styrene (Stylene) N.D. N.D. almost undetectable Ethylbenzene almost undetectable almost undetectable almost undetectable Formaldehyde N.D. N.D. 0.045

TVOC: Total Volatile Organic Compounds

It was confirmed that the TVOC emission amount of the eco-friendly ink composition according to the present invention was significantly lower than that of the conventional gravure ink composition, and the formaldehyde emission amount was also significantly reduced.

The TVOC generation amount of the binder composition for eco-friendly ink of the present invention was 0.011 mg/m ² h, which was a level suitable for environmental mark certification, and was a level that could be certified for the highest grade in the HB mark certified by the Korea Air Cleaning Association. Five VOC substances (benzene, toluene, xylene, styrene, ethylbenzene) and formaldehyde, which are restricted by the Indoor Air Quality Control Act for Multi-Use Facilities, were also not detected. Therefore, it was found that the ink composition according to the present invention is an environmentally friendly product.

10: first polymer film
20: printing layer, 30: adhesive layer
40: second polymer film

Claims (5)

A first polymer film, an eco-friendly ink printing layer laminated on one surface of the first polymer film, an adhesive layer laminated on the other surface of the printed layer, and a second polymer film laminated on the other surface of the adhesive layer,
The eco-friendly ink contains 10 to 35% by weight of polyurethane resin, 10 to 35% by weight of pigment, 5 to 10% by weight of vinyl butyral polymer, 0.5 to 5% by weight of emulsifying wax, coco 0.5 to 5% by weight of betaine and 30 to 60% by weight of an ethanol solvent,
The eco-friendly ink further includes 5 to 10% by weight of a copolymer represented by Formula 1 below,
The adhesive layer is an eco-friendly packaging film, characterized in that formed of an eco-friendly adhesive composition containing 50 to 70% by weight of polyurethane resin, 20 to 40% by weight of ethanol, and 5 to 10% by weight of a copolymer represented by the following formula (1) :
[Formula 1]

In the above formula, a, b and c represent mole fractions,
Wherein a is 0.1 to 0.4, b is 0.1 to 0.4, c is 0.3 to 0.7, and a+b+c is 1. delete delete delete According to claim 1,
The first polymer film is an oriented polypropylene (OPP) film or a polyethylene terephthalate (PET) film,
The second polymer film is an eco-friendly packaging film, characterized in that a non-stretched film (CPP), an aluminum deposition non-stretched film (VM-CPP) or a linear low density polyethylene (LLDPE) film.

Images