KR20200105048A - Lightweight bread packaging material and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a lightweight bread packaging material and a manufacturing method thereof and, more specifically, to a cast polypropylene (CPP) film comprising: a corona skin layer including random poly propylene; a core layer including block polypropylene and homo polypropylene; and a skin layer including a propylene-1-butene-ethylene copolymer. The present invention also relates to a bread packaging material using the CPP film, and to a manufacturing method thereof. According to the present invention, the thickness of the CPP film is reduced to reduce the amount of plastic packaging materials used, and at the same time, the deformation of the film appearance occurring during hot air drying, and the deformation of the film appearance occurring in a process of passing between a roll and a roll, and a discharge process by heat can be minimized. In addition, it is possible to minimize the bursting of the packaging material in a process of opening the entrance with air to put food into the packaging material during automatic packaging of food.

Description

Lightweight bread packaging material and manufacturing method thereof

The present invention relates to a lightweight bread packaging material and a method for manufacturing the same, and more specifically, to a lightweight CPP film, a lightweight bread packaging material including the same, and a manufacturing method thereof.

CPP film is a non-stretched film made of polypropylene as its main raw material. It has excellent transparency and surface gloss and excellent thermal adhesive strength. It is used as a sealant film for snack packaging and retort food packaging.

PP film (polypropylene film) is a low-cost, general-purpose resin that controls crystallinity and can be formed into a transparent film. Compared to PE, it has higher rigidity, has better surface gloss, has excellent chemical resistance, has good secondary processing ability, and is hygienic. Therefore, it does not generate harmful gas even when burned. However, due to its high melting point, the heat seal temperature is high and it is a crystalline resin. In addition, there is no hot tack and no gas barrier properties. In order to compensate for these drawbacks, PP is often used after various random copolymers have been developed and modified. PP is used in two main types. It is stretched and used as a surface layer film (BOPP), or an olefin-based polymer alone or as a blend to be used as a thermal bonding film. The PP film used for bonding is mainly made of a copolymer resin with ethylene by the T-die method. The resin used for the universal CPP thermal bonding film is a random copolymer resin having an ethylene content of about 2 to 5%. CPP film is the most commonly used film for thermal bonding for retort pouch, and it is a block copolymer of ethylene and propylene, which has properties that can withstand retort sterilization such as impact strength and heat resistance.

As the use of recently discarded CPP film packaging materials increases, there is a need to reduce the amount of discharged CPP film packaging materials, as well as the need to meet the reduction of carbon dioxide emissions according to the recent greenhouse gas reduction plan.

As a conventional prior art, Korean Utility Model Registration No. 20-0432305 relates to a sheet using a CPP film, comprising: a primer layer 11; A white CPP composite layer 12 located on the upper surface of the primer layer 11; A printing layer 13 located on the upper surface of the white CPP synthetic paper layer 12; An adhesive layer 14 located on the upper surface of the printing layer 13; A CPP film layer 15 located on the upper surface of the adhesive layer 14; And it discloses a configuration including a surface layer 16 located on the upper surface of the CPP film layer 15.

However, the sheet using the CPP film as in the prior art does not disclose a material or structure for reducing the weight of the CPP film, and also, while reducing the weight of the CPP film, the deformation of the film appearance required during the packaging material manufacturing process and prevention of the bursting of the packaging material It does not disclose a technology that can maintain or improve the quality characteristics.

Korean Utility Model Registration No. 20-0432305 (2006. 11. 24)

Accordingly, an object of the present invention is a lightweight CPP film that can reduce the amount of plastic packaging material by reducing the thickness of the CPP film, while at the same time minimizing the deformation of the film appearance that occurs during hot air drying of the CPP film, which has a reduced thickness in the packaging material manufacturing process, It is to provide a lightweight bread or food packaging material containing this and a method of manufacturing the same.

Another object of the present invention is to reduce the use of plastic packaging materials by reducing the thickness of the CPP film, and at the same time, the process of passing between rolls and rolls in the processing process of manufacturing the film in the form of a bag, and the appearance of the film occurring in the unpacking process by heat. It is to provide a lightweight CPP film capable of minimizing deformation, a lightweight bread or food packaging material including the same, and a manufacturing method thereof.

Another object of the present invention is a lightweight CPP film capable of minimizing the bursting of the packaging material in the process of opening the entrance with air to put food into the packaging material during automatic packaging of food, a lightweight bread or food packaging material including the same, and It is to provide a manufacturing method thereof.

CPP film according to a preferred embodiment of the present invention for achieving the above object, a corona skin layer including random polypropylene (Random poly propylene); Block polypropylene (Block poly propylene) and a core layer comprising a homo polypropylene (Homo poly propylene); And it may include a skin layer comprising a propylene-1-butene-ethylene copolymer (Propylene-1-butene-ethylene copolymer).

In the present invention, the term CPP (Cast Polypropylene) film refers to a film manufactured using a T-die method using PP (Polypropylene) without drawing.

In the present invention, the term homo polypropylene (HOMO PP) is composed of a single bond of propylene only, has high crystallinity, and has excellent mechanical properties such as tensile strength and stiffness. Here, the homo propylene (Homo propylene) is preferably polypropylene. -> Delete

In the present invention, the term block polypropylene (BLCOK PP) is an improvement in the low-temperature impact properties of Homo polypropylene, and is manufactured by copolymerization of propylene and ethylene, and ethylene is blocked by homopropylene. It is composed of and is copolymerized.

In the present invention, the term random polypropylene (RANDOM PP) is an ethylene-propylene copolymer that has improved transparency and flexibility in homopolypropylene, and is prepared by copolymerizing propylene and ethylene to arrange two monomers in disorder, It is used for products that require transparency and flexibility, such as food and clothing packaging.

In the present invention, the term propylene-1-butene-ethylene copolymer (Propylene-1-butene-ethylene copolymer, TER PP) is manufactured using ethylene and butene as monomers (Co-monomer) in addition to propylene, compared to homopropylene. It has excellent properties in terms of transparency and has a low melting point, so it is used as a raw material for products that need to be processed at low temperatures.

In the present invention, the term, the corona skin layer, increases the surface tension of the CPP film to facilitate printing and coating.

In addition, in the CPP film according to an embodiment of the present invention, the weight ratio of the block polypropylene and the homo polypropylene is characterized in that 70:30 ~ 30:70.

A bread packaging material or food packaging material according to a preferred embodiment of the present invention is characterized in that it comprises the CPP film.

In a method of manufacturing a food packaging material using a CPP film according to a preferred embodiment of the present invention, RANDOM PP to be introduced into the first extruder and additives are mixed, and Block PP, HOMO PP and additives to be introduced into the second extruder are mixed. , Mixing TER PP and additives to be introduced into the third extruder; Introducing each of the blended raw materials into the first to third extruders; Extruding in the first to third extruders to form a CPP film; And it may include the step of corona treatment on one side of the extruded film. At this time, the food is preferably bread.

In addition, in the manufacturing method of a food packaging material using a CPP film according to an embodiment of the present invention, the block polypropylene (Block poly propylene) is an ethylene-propylene copolymer, Homo polypropylene (Homo poly propylene) is polypropylene It is characterized in that it is a single bond of only.

According to the lightweight CPP film of the present invention, a food packaging material using the same, and a manufacturing method thereof, the present invention reduces the thickness of the CPP film to reduce the amount of use of the plastic packaging material, while at the same time reducing the thickness of the CPP film generated during hot air drying. It can minimize deformation.

In addition, it is possible to minimize the deformation of the film appearance occurring in the process of passing between the rolls and the rolls in the processing process of manufacturing the film in the form of a bag, and in the unpacking process by heat.

In addition, it is possible to minimize the bursting of the packaging material in the process of opening the entrance with air to inject food into the packaging material during automatic packaging of food.

In addition, according to the present invention, even though the thickness of the packaging material has been reduced compared to the conventional packaging material, the quality characteristics of the haze value of the film, the strength of the S/W (side welding), the defect rate of processing contact, and the shrinkage length after printing are affected. In the same manner, or more improved and excellent effect.

1 is a schematic diagram showing a conventional three-layered CPP film.
Figure 2 is a schematic diagram showing a three-layer structure CPP film according to an embodiment of the present invention.
3 is a photograph of measuring the thermal bonding strength of a portion where thermal bonding is performed according to an embodiment of the present invention.
4 is a photograph showing the presence or absence of a hole in the thermal adhesive contact according to an embodiment of the present invention.
5 is a photograph showing a deformation of a film appearance according to film shrinkage according to an embodiment of the present invention.
6 is a result of measuring physical properties and quality characteristics for Example 1 and Comparative Examples 1 to 3 according to an embodiment of the present invention.
7 is a result of measuring physical properties and quality characteristics for Comparative Examples 4 to 5 according to an embodiment of the present invention.
8 is a photograph of a cross-sectional thickness of a conventional three-layer CPP film.
9 is a photograph of a cross-sectional thickness of a three-layered CPP film according to an embodiment of the present invention.

Since the present invention may apply various transformations and may have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, when it is determined that a detailed description of a related known technology may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof does not preclude in advance.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrative purposes only, and it will not be construed that the scope of the present invention is limited by these examples.

<Example 1>

A corona skin layer including random poly propylene; Block polypropylene (Block poly propylene) and a core layer comprising a homo polypropylene (Homo poly propylene); And extruders (first to first) for manufacturing each layer to manufacture a bread packaging material having a three-layer structure consisting of a skin layer including a propylene-1-butene-ethylene copolymer. 3 extruder) is separately provided, and it is manufactured by extruding the three layers formed in each extruder. Each extruder is equipped with a separate blender, and a storage unit for storing raw materials is provided inside the blender.

First, RANDOM PP and additives to be introduced into the first extruder were mixed. Next, Block PP and HOMO PP were mixed in the same ratio in the second extruder, and additives were mixed. TER PP and additives were blended in the third extruder. The additive is an anti-blocking agent or a slip agent, and is preferably 1 to 3% of the total weight of the raw materials introduced into each extruder.

It is put in a blender at a set ratio and mixed, and then it is fed into the extruder through the hopper by 10 kg. The extrusion conditions are set at 180°C for the feed part and 230°C for the melting part with respect to the temperature of the screw inside the extruder. The melted resin passes through a feed block (mold) that forms a three-layer structure and moves to the T-DIES multi-layer extruder, and the discharge temperature of the T-DIES multi-layer extruder is set to 240°C to discharge the resin. The melted resin is molded to a certain thickness and cooled after passing through the primary and secondary cooling rolls (temperature: 22~26℃) to form a CPP film. Thereafter, the thickness is measured, passed between the roll and the roll while repeating movement left and right using an oscillator, and the cross-section undergoes a corona treatment process to impart printability, followed by an aging process after winding. After aging, the CPP film is produced after the slitting process that cuts to the required size. To make bread packaging, gravure printing or flexo printing is performed using a film. During the printing process, ink is coated on the surface of the film. This ink contains urethane resin, additives, organic solvents, and organic solvents contained in the coated ink. The drying process proceeds. At this time, for drying the organic solvent, the ink-coated film passes through the chamber and the temperature of the chamber is set at 50 to 60°C, which changes according to the coating amount. When the film passes through the chamber, the air volume is kept constant for stable running. The above-described process is a 1 degree printing process and is repeated from 1 degree to 10 degrees depending on the frequency of the finished product. In principle, shrinkage within 3mm after printing. Afterwards, in the processing process of forming into a bag, the finished product was packaged by folding the film at the part corresponding to the front standard bottom of the finished product packaging in a “M” shape and cutting it in a triangular shape at the same time in order to form the film into a finished product. When to free up space. Thereafter, both sides of the finished product packaging material are cut in a straight line with heat bonding to seal the sides. In the previous process, the part cut in a triangular shape and the part cut in a straight line are matched at the contact point to produce a normal product. When inserting and sealing the contents into one packaging material, use air to open the entrance to open the packaging material, insert the contents such as bread, and seal the opening opening.

<Examples 2 to 3>

In Example 1, the weight ratio of block polypropylene and Homo polypropylene to the second extruder was 70:30 (Example 2) and 30:70 (Example 3). Except for the remaining steps, the same was performed.

<Comparative Examples 1 to 3>

In Example 1, 100% of block polypropylene (Comparative Example 1), 100% of Homo polypropylene (Comparative Example 2), and 100% of TER PP in the second extruder (Comparative Example 1) Except for Comparative Example 3), the remaining steps were carried out in the same manner. At this time, the film thickness of Comparative Examples 1 to 3 was manufactured to be thinner than the thickness of the conventional packaging material (about 40 μm) to have the same thickness as the film of Example 1 (about 30 μm).

For Example 1 and Comparative Examples 1 to 3, properties such as haze, S/W strength, defect rate at the machined contact point, and shrinkage length after printing were evaluated, and the results are summarized in Table 1.

S/W (Side welding) process is a CPP film that has been printed in a roll form, but in the process of processing it into a bag, it is necessary to cut it one by one and heat-bond and seal it outside the two sides of the envelope entrance and the folded side (M-shaped). , At this time, the S/W (Side welding) process refers to the process of sealing (heat bonding) the two sides of the envelope while cutting it with a heat knife.

Defect rate at the processing contact means that when processing the packaging material into a bag form, it is necessary to secure a space for the contents of the packaging material, so in order to make the bottom surface of the packaging material wider, it is folded in an “M” shape and folded in an M shape in the process of removing unnecessary parts. There is a contact point where the intestinal packaging material and the two packaging materials in the body of the packaging material meet, and if these contact points do not match, a major problem occurs in the shelf life due to the influence of foreign substances and internal atmosphere pollution (refer to Figure 4). It refers to the defective rate.

According to Table 1, when using 100% Homo PP, problems occurred in the transparency and productivity of the packaging material (poor S/W strength) due to an increase in the haze value of the film and an increase in the strength (HARDNESS).

When using 100% of TER PP, the haze value of the film is increased, the softness is increased, heat resistance and dimensional safety are reduced, so a problem occurred in the appearance and productivity of the packaging material (failure to check the processed contact).

When using 100% BLOCK PP, the productivity of the packaging material was degraded due to the influence of the S/W strength and the results of the process contact check test.

Example 1 including a core layer of BLOCK PP and Homo PP was reduced to 30 μm in thickness compared to the conventional 40 μm-thick packaging material, but cloudiness, S/W strength, defect rate at processed contact points, after printing In terms of characteristics such as shrinkage length, it was possible to obtain an excellent effect showing the same or improved quality characteristics as those of the conventional 40 μm-thick packaging material.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Based on conventional 40㎛ thickness, TER PP 100% Cloudiness (%) 1.4 2.2 2.5 2.2 2.0 or less S/W intensity measurement result 3% 8% 15% 4% Defect rate 3% Machining contact check result 2% 9% 3% 13% Defect rate 3% Shrink length after printing (mm) Within 3 Within 3 5-6 Within 3 3 or less

The results of measuring physical properties and quality characteristics for Example 1 and Comparative Examples 1 to 3 are shown in FIG. 6.

<Comparative Examples 4 to 5>

In Example 1, the weight ratio of block polypropylene and homo polypropylene to the second extruder was 80:20 (Comparative Example 4) and 20:80 (Comparative Example 5). Except for the remaining steps, the same was performed.

For Examples 2 to 3 and Comparative Examples 4 to 5, characteristics such as haze, S/W strength, defect rate at the machined contact point, and shrinkage length after printing were evaluated, and the results are summarized in Table 2. .

According to Table 2, it is preferable that the weight ratio of block polypropylene and homo polypropylene in the core layer is 70:30 ~ 30:70, which is a block polypropylene component of 30 If the content is added in an amount of less than% by weight, there is a problem of technical defects or an increase in the defect rate in terms of transparency, haze, and shrinkage length increase. On the contrary, when the homopropylene component is added in an amount less than 30% by weight, the defect rate due to S/W strength Because it increases.

Example 2 Example 3 Comparative Example 4 Comparative Example 5 Based on conventional 40㎛ thickness, TER PP 100% Cloudiness (%) 2.0 2.0 2.3 2.5 2.0 or less S/W intensity measurement result 5 6 11 13 Defect rate 3% Machining contact check result 3 3 11 5 Defect rate 3% Shrink length after printing (mm) Within 3 Within 3 3-5 Within 3 3 or less

7 shows the results of measuring physical properties and quality characteristics for the Comparative Examples 4 to 3.

Meanwhile, in the above, the present invention has been illustrated and described in connection with specific preferred embodiments, but the present invention is variously modified and modified within the scope of not departing from the technical features or field of the present invention provided by the following claims. It is obvious to one of ordinary skill in the art that it can be changed.

Claims (9)

A corona skin layer including random poly propylene;
Block polypropylene (Block poly propylene) and a core layer comprising a homo polypropylene (Homo poly propylene); And
A skin layer comprising a propylene-1-butene-ethylene copolymer;
CPP (Cast Polypropylene) film comprising a.
The method of claim 1,
CPP film, characterized in that the weight ratio of the block polypropylene (Block poly propylene) and homo polypropylene (Homo poly propylene) is 70:30 ~ 30:70.
The method of claim 1,
The random polypropylene (Random poly propylene) is a CPP film, characterized in that the ethylene-propylene copolymer.
The method of claim 1,
The block polypropylene (Block poly propylene) is an ethylene-propylene copolymer, Homo polypropylene (Homo poly propylene) is a CPP film, characterized in that the single bond of propylene.
A food packaging material comprising the CPP film according to any one of claims 1 to 4.
The method of claim 5, wherein the food is bread.
Blending RANDOM PP and additives to be introduced into the first extruder, blending Block PP, HOMO PP and additives to be introduced into the second extruder, and mixing TER PP and additives to be introduced into the third extruder;
Introducing each of the blended raw materials into the first to third extruders;
Extruding in the first to third extruders to form a CPP film; And
Corona treatment on one side of the extruded film;
A method of manufacturing a lightweight food packaging material comprising a.
The method of claim 6,
The block polypropylene (Block poly propylene) is an ethylene-propylene copolymer, Homo polypropylene (Homo poly propylene) is a method of manufacturing a lightweight food packaging material, characterized in that the polypropylene.
The method of claim 7 or 8, wherein the food product is bread.

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