KR101316941B1 - Breathable film composition applied hot pack and manufacturing method of breathable film including thereof - Google Patents

Abstract

PURPOSE: An air permeable film composition for hot packs is provided to be able to maintain a low air permeability suitable for hot packs for a long time, and to be able to control the heating temperature and the heating duration time of a heating element. CONSTITUTION: An air permeable film composition comprises a metallocene catalyst polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler and an additive. The metallocene catalyst polyolefin resin and the linear low density polyethylene resin simultaneously satisfy Chemical formula 1: 0.915<=D<=0.940, Chemical formula 2: 2.0<=MI<=5.0, Chemical formula 3: 85deg.C<=Tv<=120deg.C and Chemical formula 4: 100deg.C<=Tm<=130deg.C. In the Chemical formulas, D is a density (g/cm^3, 25deg.C), MI is a melt flow index (g/10 min, 190deg.C, 2.16 kg), Tv is a Vicat softening point (deg.C), and Tm is a melting point (deg.C).

Description

The breathable film composition applied to the hot pack and the manufacturing method of the breathable film for a hot pack including the same {BREATHABLE FILM COMPOSITION APPLIED HOT PACK AND MANUFACTURING METHOD OF BREATHABLE FILM INCLUDING THEREOF}

The present invention relates to a breathable film composition applied to a hot pack and a method for manufacturing a breathable film for a hot pack including the same. The present invention relates to a breathable film composition applied to a finely controllable hot pack and a method for manufacturing a breathable film for a hot pack including the same.

Breathable film is a film that allows gas such as air and steam to pass but does not allow liquid such as water to pass through. Disposable clothing such as covers for disposable diapers and disposable women's products, sportswear, protective clothing, waterproof clothing, construction house wraps, packaging materials, It is used for various purposes such as sanitary materials. Since the physical properties required for each product to which the breathable film is applied are different, in order to maintain suitable properties for each use, the type and content of the breathable film compound composition must be appropriately designed, and a manufacturing method of the film must be developed.

For a long time, we have been using heated stones for relieving the cold, and today, using the heat function of the hot pack, to go beyond the simple body warming function used for cold weather during outdoor activities on the cold day, to medical treatment to relieve pain. It is diverse and expanding rapidly. As a result, demand for breathable films for packaging heating elements of hot packs is increasing.

Breathable film applied to the hot pack is to be able to maintain a constant and constant temperature of the body parts attached by allowing to finely control the exothermic temperature and the exothermic duration of the heating element according to the ventilation.

The principle of oxidation reaction of heating element applied to hot pack is as follows.

Fe + 3/4 O ₂ + 3/2 H ₂ O → Fe (OH) ₃ + 96 kcal / mol

The heating element is composed of pure iron, activated carbon, salts, porous inorganics, and the like containing some moisture and air to promote oxidation. In order to control the temperature generated by the oxidation reaction, the content of iron and other additives included in the heating element are controlled, but there is a limit in controlling the exothermic temperature and the exothermic duration.

In the case of hot packs, direct or indirect contact with the human body increases the amount of oxygen in contact with iron, causing a rapid increase in the exothermic temperature, which poses a risk of self-burning. Since the same problem may occur, the degree of heat generation can be controlled, and the importance of a breathable film having a small variation in airflow is emerging.

Such a breathable film can be produced by various methods, but among them, an inorganic filler is mixed with a polyolefin resin to make a compound, and then molded into a film, and the film is biaxially or uniaxially stretched to form an interface between the resin and the filler. The method of physically separating and forming breathable micropores to secure breathability is the most widely used method.

Republic of Korea Registration No. 10-0358711 (Patent Document 1) to use the ethylene-based low crystalline polymer to have a high processability when forming a film to enable high-speed production, but due to the low crystalline polymer properties of the film is poor Due to high-speed production, it is not easy to control fine pores, so there is a big problem in mechanical property deterioration and aeration deviation.

In addition, Republic of Korea Patent No. 10-0987398 (Patent Document 2) is applied to two sheets of film in order to minimize the deviation of the air permeability of the film with a high air permeability and both ends of the film having a weak air permeability in order to reduce the variation of air permeability In order to reduce the deviation by adjusting the air permeability by the amount of the pressure-sensitive adhesive, there was a problem that the increase in the manufacturing cost and the variation in mechanical properties due to the change in the pressure-sensitive adhesive content increases.

Therefore, it is possible to maintain a low level of air permeability suitable for the hot pack steadily, the situation is required to develop a composition for a breathable film and a manufacturing process of the film that significantly reduced the variation of the air permeability.

Republic of Korea Registration No. 10-0358711 Republic of Korea Patent No. 10-0987398

In order to solve the above problems, a single layer or multilayer film is uniaxially or biaxially stretched by using a breathable film composition for a hot pack including a metallocene catalyst-based polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler and an additive. By manufacturing a, it is possible to maintain a low air permeability suitable for a hot pack for a long time, it is an object to provide a breathable film composition for a hot pack that can control the exothermic temperature and the exothermic duration of the heating element.

Moreover, it aims at providing the breathable film for hot packs containing the breathable film composition for hot packs.

In addition, it is an object of the present invention to provide a breathable film for hot packs, which is easy to process even at low temperatures due to high thermal adhesive strength and mechanical strength.

Moreover, it aims at providing the manufacturing method for manufacturing the breathable film for hot packs.

The present invention for achieving the above object comprises a metallocene catalyst polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler and an additive, the metallocene catalyst polyolefin resin and a linear low density polyethylene resin It is related with the breathable film composition for hot packs which satisfy | fills 1 and Formula 2.

0.915 ≤ D ≤ 0.940 [Equation 1]

2.0 ≤ MI ≤ 5.0 [Equation 2]

(In Equation 1, D is density (g / cm 3, 25 ° C.), and MI in Equation 2 is melt flow index (g / 10 min, 190 ° C., 2.16 kg).

The metallocene catalyst polyolefin resin and the linear low density polyethylene resin may simultaneously satisfy the following Equations 3 and 4 below.

85 ° C ≤ T _v ≤ 120 ° C [Equation 3]

100 ° C ≤ T _m ≤ 130 ° C [Equation 4]

(In Equation 3, T _v is the Vicat softening point (° C.), and T _m in Equation 4 is the melting temperature (° C.).)

The metallocene catalyst-based polyolefin resin may include 30 to 50% by weight, linear low density polyethylene resin 5 to 60% by weight, low density polyethylene resin 3 to 8% by weight, inorganic filler 5 to 50% by weight and additives 0.5 to 10% by weight. have.

The metallocene catalyst-based polyolefin resin includes linear low density polyethylene or 1-butene, 1-pentene, 1-hexene, 4-methylpentene, 1-heptene, 1-octene, and 1-decene polymerized using a metallocene catalyst. It may include any one or two or more compounds selected from the group consisting of ethylene olefin block copolymer comprising.

The hot pack breathable film composition may further include a heat adhesion improver further 1 to 20% by weight, wherein the heat adhesion improver has a melt flow index of 0.5 to 50 g / 10min and a density of 0.925 to 0.950 g / cm 3. Ethylene vinyl acetate or metallocene polyethylene having a density of 0.850 to 0.900 g / cm 3.

The present invention for achieving the above object comprises a breathable film composition for a hot pack described above, and relates to a breathable film for a hot pack formed in a single layer or multiple layers.

The breathable film for hot packs formed in the multilayer is formed of an outer layer / middle layer / outer layer, and the extrusion ratio of the outer layer: middle layer: outer layer may be 1: 4 to 8: 1 to 3.

The hot pack breathable film may satisfy the following Equations 5 and 6.

4,000 ≤ P _air ≤ 20,000 [Equation 5]

10 ≤ | P _air | ≤ 20 [Equation 6]

(In Formula 3, Pair is the air permeability of the breathable film for hot packs (sec / 100cc), and in Formula 4, | P _air | is the deviation of air permeability of the breathable film for hot packs (%).)

In addition, the present invention for achieving the above object is a) preparing a breathable compound by mixing a breathable film composition comprising a metallocene catalyst-based polyolefin resin, linear low density polyethylene resin, low density polyethylene resin, inorganic filler and additives ; b) extruding or coextruding the breathable compound to produce a single or multilayer unstretched film; And c) uniaxially or biaxially stretching the non-stretched film to prepare a breathable film.

The breathable film composition is 30 to 50% by weight of the metallocene catalyst-based polyolefin resin, 5 to 60% by weight of linear low density polyethylene resin, 3 to 8% by weight of low density polyethylene resin, 5 to 50% by weight of inorganic filler and 0.5 to 10% by weight of additive May contain%.

When the multi-layer unstretched film is manufactured by coextrusion of the breathable compound in step b), the multilayer unstretched film is formed of an outer layer / middle layer / outer layer, and the extrusion ratio of the outer layer: middle layer: outer layer is 1: 4. 8 to 1 to 3, the stretching ratio during uniaxial or biaxial stretching may be 3.0 to 6.0 times.

According to the breathable film composition applied to the hot pack of the present invention and a method for producing a breathable film for a hot pack including the same, a single layer or a multilayer including a metallocene-based polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler and an additive Regardless of the location to be manufactured by forming a breathable film, the ventilation per unit area appears uniformly, has excellent mechanical properties, and has an advantage of easy processing by forming a low thermal bonding temperature.

Hereinafter, a preferred embodiment and a method for measuring physical properties of a breathable film composition applied to a hot pack of the present invention and a method for manufacturing a breathable film for a hot pack including the same will be described in detail.

The present invention relates to a breathable film composition for application to a hot pack, comprising a metallocene catalyst-based polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, inorganic fillers and additives having a predetermined density and melt flow index Extruded and uniaxially / biaxially stretched to form a single layer / multi-layer, keeping the air permeability constant regardless of the position of the film to be produced, thereby minimizing the air permeability deviation, and found that the exothermic temperature and the exothermic duration of the heating element can be more freely controlled. It was completed.

Hereinafter, the breathable film composition for a hot pack of the present invention will be described in detail.

The breathable film composition for a hot pack according to an embodiment of the present invention may include a metallocene catalyst-based polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler, and an additive.

The metallocene catalyst-based polyolefin resin is not limited to the polyolefin resin surface polymerized using a metallocene catalyst known in the art, for example, linear low density polyethylene or 1-polymerized using a metallocene catalyst. May comprise any one or two or more compounds selected from the group consisting of ethylene olefin block copolymers including butene, 1-pentene, 1-hexene, 4-methylpentene, 1-heptene, 1-octene and 1-decene have.

 Linear low density polyethylene resins are also not limited as long as linear low density polyethylene resins are known in the art, and ethylene including 1-pentene, 1-hexene, 4-methylpentene, 1-heptene, 1-octene and 1-decene Copolymers and mixtures thereof can be used.

When the ethylene copolymer is composed of polyethylene composed of 1-hexene or 1-octene, it is preferable to use 1-hexene polyethylene in an amount of 0.5 to 2 times that of 1-octene polyethylene.

In addition, the linear low density polyethylene having different copolymerization monomers is effective because the melt flow index and the density are similar, so that the rheological difference is not large, thereby lowering the air permeability and reducing the deviation of the air permeability.

The metallocene catalyst-based polyolefin resin and the linear low density polyethylene resin according to the embodiment of the present invention preferably satisfy the following Formulas 1 and 2.

0.915 ≤ D ≤ 0.940 [Equation 1]

2.0 ≤ MI ≤ 5.0 [Equation 2]

(In Equation 1, D is density (g / cm 3, 25 ° C.), and MI in Equation 2 is melt flow index (g / 10 min, 190 ° C., 2.16 kg).

When the density (D) is less than 0.915 g / cm 3, a problem may occur in that the tensile strength of the breathable film is significantly lowered and the elongation is maintained more than necessary. When the density (D) is more than 0.940 g / cm 3, the stretching may be performed. The non-uniformity causes the physical properties of the breathable film not to appear uniformly, and may cause a problem that the variation in airflow increases depending on the location of the breathable film.

In addition, when the melt flow index (MI) is less than 2 g / 10 min, the processing load increases during molding of the breathable film, the productivity is lowered, the flowability of the melt is not constant, the formability of the breathable film is unstable, 5 If it is more than g / 10min may cause a problem that the mechanical properties of the film is sharply reduced.

In addition, it is preferable that the metallocene catalyst-based polyolefin resin and the linear low density polyethylene resin satisfy the following formulas (3) and (4).

85 ° C ≤ T _v ≤ 120 ° C [Equation 3]

100 ° C ≤ T _m ≤ 130 ° C [Equation 4]

(In Equation 3, T _v is the Vicat softening point (° C.), and T _m in Equation 4 is the melting temperature (° C.).)

Therefore, the metallocene catalyst-based polyolefin resin and the linear low density polyethylene resin have the density, melt flow index, Vicat softening point and melting temperature in the above-described range, so that the air permeability suitable for the hot pack can be maintained uniformly, and the air permeability variation between sections is maintained. It is effective because it can reduce.

It is preferable that the metallocene catalyst-based polyolefin resin is 30 to 50% by weight and the linear low density polyethylene resin is 5 to 60% by weight based on 100% by weight of the total breathable film composition, and more preferably the metallocene catalyst-based polyolefin resin Is 33 to 41% by weight, the linear low density polyethylene resin is 9 to 56% by weight is excellent in processability, and is effective because it is suitable for the manufacture of a breathable film that can reduce the deviation.

When the metallocene catalyst-based polyolefin resin is less than 30% by weight, and the linear low density polyethylene resin is less than 5% by weight, the workability of the breathable film may decrease or pinholes may occur, and the metallocene catalyst-based polyolefin resin is more than 50% by weight. If the linear low-density polyethylene resin is more than 60% by weight, there is a possibility that a problem that the air permeability is significantly reduced.

Low-density polyethylene resin according to an embodiment of the present invention is added to improve the stability of the work, the density is preferably 0.915 to 0.925g / cm 3 (25 ℃), the melt flow index (MI) is 3 to 20g / It is preferable that it is 10min (190 ° C, 2.16 kg).

The content of the low density polyethylene resin is preferably contained 3 to 8% by weight, more preferably 4 to 7% by weight relative to the total 100% by weight of the breathable film composition of the present invention. If the low-density polyethylene resin is less than 3% by weight, the effect of improving the stability of the work is insignificant, and the workability is reduced, and if it is more than 8% by weight, mechanical properties may decrease, so it is effective to include the above-mentioned range. to be.

In addition, the inorganic filler according to an embodiment of the present invention can be used without limitation as long as it is an inorganic filler known in the art, for example, calcium carbonate, silica, barium sulfate, calcium sulfate, talc, kaolin, oxidation One, two or more may be selected from aluminum, mica, zeolite, diatomaceous earth, magnesium carbonate, clay, aluminum hydroxide or magnesium hydroxide. More preferably, an organic acid such as stearic acid is coated on the surface of the inorganic filler to uniformly disperse the inorganic filler in the breathable film composition.

The inorganic filler is not limited to a plate or granular form, and is fine particles having an average particle diameter of 1.0 to 3.0 μm in order to form uniform pores and maintain mechanical properties in the process of forming pores by stretching, and preferably have a large specific surface area. In particular, fine particles formed of calcium carbonate are preferred.

When the average particle diameter of the inorganic filler is less than 1.0 μm, the dispersibility of the inorganic filler may be decreased when manufacturing the breathable film composition, and workability may be reduced due to an increase in processing load. When the average particle size is more than 3.0 μm, There is a problem that it is difficult to control the air permeability and deviation of the film.

The content of the inorganic filler is preferably 5 to 50% by weight, more preferably 30 to 50% by weight, based on 100% by weight of the total air permeable film composition of the present invention.

If the content of the inorganic filler is less than 5% by weight, it is difficult to produce fine pores of the film, so that the air permeability is excessively lowered, and when the content of the inorganic filler is greater than 50% by weight, it is difficult to realize the physical properties and uniform breathing deviation of the breathable film, and the appearance of the film Since a bad problem may occur, it is most effective to include the above-mentioned range.

In addition, the breathable film composition for a hot pack of the present invention may further include additives such as antioxidants, lubricants and titanium dioxide for improving whiteness and hiding power to improve the physical properties and processability of the breathable film, as described above The additive can be used without limitation as long as it is obvious in the art.

The content of the additive is preferably included in an amount of 0.1 to 10% by weight, more preferably 1 to 3% by weight based on 100% by weight of the total breathable film composition of the present invention.

If the content of the additive is less than 0.1% by weight may cause a problem that the workability of the breathable film is lowered, when the content of more than 10% by weight may cause a problem of reducing the physical properties of the breathable film, it is included in the above range Most effective.

The breathable film composition according to an embodiment of the present invention may further include a heat adhesion improving agent, wherein the heat adhesion improving agent has a melt flow index of 0.5 to 50 g / 10min and a density of 0.925 to 0.950 g / cm 3. Effective is ethylene vinyl acetate or metallocene polyethylene having a density of 0.850 to 0.900 g / cm 3.

By including a heat-adhesion enhancer, it is easy to heat bond between the breathable film at low temperature, improve the heat-bond strength to increase the production speed of the hot pack manufacturing process, improve the peel strength with the film is heat-bonded There is an advantage to improve the durability.

The metallocene polyethylene of the thermal adhesion improver has a low softening point of 35 to 90 ℃ can widen the thermal bonding temperature range, ethylene vinyl acetate has a low softening point is easy to heat bond at low temperatures, the production speed of the hot pack It can be improved, and is cheaper than other ethylene-alpha-olefin-based copolymers, so that the mechanical properties can be preferentially applied within the effective range, thereby effectively reducing the process cost.

The content of the heat adhesion improving agent is preferably included 1 to 20% by weight, more preferably 10 to 15% by weight relative to 100% by weight of the total breathable film composition of the present invention.

If the thermal adhesion improver is less than 1% by weight, thermal adhesion may not be easy at low temperatures, and the improvement of thermal adhesion strength may be insignificant.If the thermal adhesion enhancer is more than 20% by weight, the mechanical properties are reduced and the ventilation is kept low. Since it may be difficult to cause problems, it is effective to add in the above-described range in order to implement more effective thermal adhesive strength.

Hot pack breathable film according to an embodiment of the present invention includes the above-mentioned breathable film composition, it is preferably formed in a single layer or multiple layers.

The multi-layer breathable film for hot packs may be formed as an outer layer / middle layer / outer layer, and the extrusion rate ratio of the outer layer: middle layer: outer layer is 1: 4 to 8: 1 to 3, indicating a uniform breathability. Regardless of the location where the film is manufactured, the permeability of the sections may be reduced.

Such, the breathable film for a hot pack according to an embodiment of the present invention may satisfy the following equations 5 and 6.

4,000 ≤ P _air ≤ 20,000 [Equation 5]

10 ≤ | P _air | ≤ 20 [Equation 6]

(In Formula 3, Pair is the air permeability of the breathable film for hot packs (sec / 100cc), and in Formula 4, | P _air | is the deviation of air permeability of the breathable film for hot packs (%).)

The breathable film for a hot pack of the present invention has a deviation of the air permeability and the air permeability of the above-described range, it is possible to maintain a uniform low air permeability suitable for the hot pack for a long time, regardless of the position where the film is manufactured, There is little variation, so there is an advantage in that the heating temperature and the heating duration of the heating element can be freely adjusted.

Hereinafter, a method of manufacturing a breathable film for hot packs of the present invention will be described in detail.

The present invention comprises the steps of: a) mixing a breathable film composition comprising a metallocene catalyst-based polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler and an additive to prepare a breathable compound;

b) extruding or coextruding the breathable compound to produce a single or multilayer unstretched film; And

c) uniaxially or biaxially stretching the non-stretched film to produce a breathable film.

The breathable film composition is 30 to 50% by weight of the metallocene catalyst polyolefin resin, 5 to 60% by weight of linear low density polyethylene resin, 3 to 8% by weight of low density polyethylene resin, 5 to 50% by weight of inorganic filler and 0.5 to 10% by weight of additives It is preferable to include, and the detailed description of each configuration is the same as described above.

When the multi-layer unstretched film is manufactured by coextrusion of the breathable compound in step b), the multilayer unstretched film is formed of an outer layer / middle layer / outer layer, and the extrusion ratio of the outer layer: middle layer: outer layer is 1: 4. It is preferable that it is formed from 8 to 1-3, and it is preferable that the content ratio of the inorganic filler of an outer layer: middle layer: outer layer is also 1: 1: 1-2: 1.

When the multi-layer breathable film is produced in the above range, the air permeability can be further reduced, it is effective because it can improve the mechanical properties.

In addition, the stretching ratio in the uniaxial or biaxial stretching in step c) is preferably 3.0 to 6.0 times.

If the draw ratio is less than 3.0 times, the tensile strength decreases as the elongation decreases, and thus mechanical properties are difficult to apply to the hot pack. If the draw ratio is more than 6 times, it is difficult to realize low ventilation and the variation of the ventilation is insignificant. Therefore, it is effective to draw in the above-mentioned range and to manufacture the breathable film for hot packs.

Hereinafter, the present invention may be better understood by the following examples, which are intended to illustrate the present invention and are not intended to limit the protection scope of the present invention.

Property measurement

1. Mechanical Properties

Mechanical properties (tensile strength and elongation) of the breathable film for hot packs of the present invention were measured by the KS M3016 standard using a universal testing machine.

2. Moisture permeability

The moisture permeability of the breathable film for hot packs of the present invention was measured by ASTM E96-92 standard under constant temperature and humidity conditions, and the moisture permeability according to the increase in weight was measured.

3. Aeration

The air permeability of the breathable film for hot packs of the present invention was measured according to JIS P8117 standard.

4. Aeration and deviation

3) In one sample of the breathable film for a hot pack of the present invention, 3) the difference between the average values measured 10 times at 10 different spots based on the values measured at the time of measurement of air permeability is expressed as a percentage.

5. Thermal bond strength

The thermal adhesive strength of the breathable film for hot packs of the present invention was measured using a universal testing machine in accordance with the ASTM F88 standard.

6. Formability

Taking a breathable film for the hot pack produced by the manufacturing method of the present invention by visual inspection it is described as "good" when the surface is uniform, and described as "pinhole generation" when the surface is poor and a pinhole or the like.

Example 1

As shown in Table 1 below, linear low density polyethylene (metallocene LLDPE (a), density: 0.918 g / cm ³ , melt flow index (190 ° C., 2.16 kg) using a metallocene catalyst: 3.7 g / 10 minutes , Softening point: 107 ° C) 70 parts by weight, linear low density polyethylene (linear LLDPE (c), density: 0.923 g / cm ³ , melt flow index (190 ° C, 2.16kg): 3.2 g / 10 min using Ziglanata catalyst) 20 parts by weight of softening point: 105 ° C., low density polyethylene (LDPE (d), density: 0.919 g / cm ³ , melt flow index (190 ° C., 2.16 kg): 7.5 g / 10 min, softening point: 85 ° C.) 1 part by weight of calcium stearate (Songwon Industry), 0.6 parts by weight of antioxidant (Hannon Adeka ADK2112), 1.5 parts by weight of titanium dioxide (HUNTSMAN, TRONOX TR28) were added to the blender, mixed for 10 minutes, and the extrusion temperature was 200 ° C. 70 parts by weight of an inorganic material (calcium carbonate (a)) coated with stearic acid having an average particle diameter of 1.2 占 퐉 and a stearic acid coated Melt extrusion was carried out while charging into a uniformly mixed breathable film composition was prepared. The prepared breathable film composition was uniaxially extruded with a T-die film molding machine at a temperature of 210 to 230 degrees, and a breathable film having a basis weight of 50 g / m ² was formed by four-fold stretching, and the physical properties thereof are shown in Table 2.

[Example 2]

As shown in Table 1 below, linear low density polyethylene (linear LLDPE (c), density: 0.923 g / cm ³ , melt flow index (190 ° C., 2.16 kg): 3.2 g / 10 min, softening point: 105 ° C.) 90 weight Part, low density polyethylene (LDPE (d), density: 0.919 g / cm ³ , melt flow index (190 ° C., 2.16 kg): 7.5 g / 10 min, softening point: 85 ° C.) 10 parts by weight, calcium stearate (Songwon Industry) 1 part by weight, 0.6 parts by weight of antioxidant (Hanong Adeka, ADK2112), 1.5 parts by weight of titanium dioxide (HUNTSMAN, TRONOX TR28) were added to the blender, mixed for 10 minutes, and then the extrusion temperature was maintained at 200 ° C. Injected into the inlet, the average particle diameter is 1.2㎛, 60 parts by weight of the inorganic material (calcium carbonate (a)) coated with stearic acid was melt-extruded while feeding into the side inlet of the twin screw extruder to prepare a uniformly mixed breathable film composition.

The air permeable film composition prepared above was introduced into an outer layer extruder, and only the inorganic filler (calcium carbonate (a)) was changed to 100 parts by weight of the air permeable film composition prepared in Example 1, and then introduced into a multi-layer extruder to transfer the film from the T-die film forming machine. Three-layer extrusion amount ratio of the outer layer / middle layer / outer layer was configured to 1: 8: 1 to prepare a film under the same conditions as in Example 1 and the physical properties are shown in Table 2.

[Example 3]

As shown in Table 1 below, linear low density polyethylene (linear LLDPE (c), density: 0.923 g / cm ³ , melt flow index (190 ° C., 2.16 kg): 3.2 g / 10 min, softening point: 105 ° C.) 70 weight Part 2, linear low density polyethylene (metallocene LLDPE (b), density: 0.870 g / cm ³ , melt flow index (190 ℃, 2.16 kg): 5.0 g / 10 minutes, softening point: 37 ℃) using a metallocene catalyst 20 parts by weight, and the remaining conditions were the same as in Example 2 to prepare a breathable film composition.

The prepared breathable film composition was introduced into an outer layer extruder, and the middle layer breathable film composition of Example 2 was introduced into a middle layer extruder, and the ratio of the three-layer extrusion amount of the outer layer / middle layer / outer layer of the film in the T-die film molding machine was 1: 8: It was composed of 1 and the film was prepared under the same conditions as in Example 2 and the physical properties thereof are shown in Table 2.

Comparative Example 1

As shown in Table 1 below, linear low-density polyethylene (linear LLDPE (c), density: 0.923 g / cm ³ , melt flow index (190 ° C., 2.16 kg)) without using metallocene LLDPE: 3.2 g / 10 min. , Softening point: 105 ° C) 90 parts by weight, low density polyethylene (LDPE (d), density: 0.919 g / cm ³ , melt flow index (190 ° C, 2.16kg): 7.5 g / 10 min, softening point: 85 ° C) 10 weight parts Part, an inorganic filler (calcium carbonate (a)) was changed to 90 parts by weight, and the remaining conditions were the same as in Example 1 to prepare a breathable film composition.

The compound was uniaxially extruded at a temperature of 210 ° C. to 230 ° C. with a T-die film molding machine, and a breathable film having a basis weight of 50 g / m ² was formed by four-fold stretching, and the physical properties thereof are shown in Table 2.

Comparative Example 2

As shown in Table 1 below, only 70 parts by weight of the inorganic filler (calcium carbonate (b)) coated with stearic acid was changed to an average particle diameter of 3.2 μm in the compound composition applied in Example 1, and the remaining conditions were the same as those in Example 1. A breathable film composition was prepared under the conditions.

The prepared breathable film composition was uniaxially extruded with a T-die film molding machine at a temperature of 210 to 230 ° C., and a breathable film having a basis weight of 50 g / m ² was obtained by 4 times stretching, and the physical properties thereof are shown in Table 2.

[Comparative Example 3]

As shown in Table 1, except that the breathable film composition prepared in Example 1 was stretched twice with a T-die film molding machine, the rest of the conditions were carried out in the same manner as in Example 1 50 g / m ² Phosphorus breathable film was prepared and its physical properties are shown in Table 2.

[Table 1]

[Table 2]

As shown in Table 2, in the case of Example 1, it was formed as a single layer, but compared to Comparative Examples 1 to 3 implements a low ventilation, it can be seen that the deviation of the ventilation is low, and also shows excellent thermal adhesive strength Can be. In addition, it can be seen that Examples 2 and 3 show improved physical properties than the single layer by forming the breathable film in multiple layers. As shown in Example 3, as the metallocene polyethylene having a lower softening point is used to improve the thermal adhesive strength, As the heat adhesion strength was the best and appeared, it was found to have the most suitable physical properties for the productivity of the hot pack.

On the contrary, in the case of Comparative Example 1, as it was formed as a single layer without including the metallocene catalyst-based polyolefin resin and the heat adhesion improving agent, the air permeability was too low, the moisture permeability increased, and the moldability of the film such as pinhole generation was also poor.

In addition, in the case of Comparative Example 2, when the average particle diameter of the inorganic filler exceeds 3.0㎛, the variation in air permeability was severe, and the moldability of the film was also poor. It turned out that it shows the unsuitable physical property.

Therefore, by adjusting the manufacturing process of the film composition and the film for the hot pack breathable according to the present invention was able to obtain a low ventilation and uniform air permeability deviation, it was confirmed that this is the optimal condition for application for the hot pack.

Although described in detail with respect to the preferred embodiment of the present invention as described above, those of ordinary skill in the art, without departing from the spirit and scope of the invention defined in the appended claims Various modifications may be made to the invention. Therefore, the present invention is not limited to the above embodiments.

Claims (12)

Metallocene catalyst-based polyolefin resin, linear low density polyethylene resin, low density polyethylene resin, inorganic filler and additives,
The metallocene catalyst-based polyolefin resin and the linear low density polyethylene resin at the same time satisfying the following formula 1 to formula 4 for a breathable film composition for hot packs.
0.915 ≤ D ≤ 0.940 [Equation 1]
2.0 ≤ MI ≤ 5.0 [Equation 2]
(In Equation 1, D is density (g / cm 3, 25 ° C.), and MI in Equation 2 is melt flow index (g / 10 min, 190 ° C., 2.16 kg).
85 ° C ≤ T _v ≤ 120 ° C [Equation 3]
100 ° C ≤ T _m ≤ 130 ° C [Equation 4]
(In Equation 3, T _v is the Vicat softening point (° C.), and T _m in Equation 4 is the melting temperature (° C.).) delete The method of claim 1,
The hot pack including the metallocene catalyst-based polyolefin resin 30 to 50% by weight, linear low density polyethylene resin 5 to 60% by weight, low density polyethylene resin 3 to 8% by weight, inorganic filler 5 to 50% by weight and additives 0.5 to 10% by weight. Breathable film composition for use. The method of claim 1,
The metallocene catalyst-based polyolefin resin includes linear low density polyethylene or 1-butene, 1-pentene, 1-hexene, 4-methylpentene, 1-heptene, 1-octene, and 1-decene polymerized using a metallocene catalyst. Ethylene olefin block copolymer comprising a breathable film composition for a hot pack comprising any one or two or more compounds selected from the group consisting of. The method of claim 1,
The hot pack breathable film composition may further include a heat adhesion improver further 1 to 20% by weight, wherein the heat adhesion improver has a melt flow index of 0.5 to 50 g / 10min and a density of 0.925 to 0.950 g / cm 3. A breathable film composition for hot packs, which is ethylene vinyl acetate or metallocene polyethylene having a density of 0.850 to 0.900 g / cm 3. A breathable film for a hot pack comprising a breathable film composition for a hot pack of any one of claims 1 to 5, and formed in a single layer or multiple layers. The method according to claim 6,
The hot pack breathable film formed of the multi-layer is formed of an outer layer / middle layer / outer layer, the outer layer: the middle layer: the outer layer is a hot pack breathable film is formed in the ratio of 1: 4 to 8: 1-3. The method according to claim 6,
The hot pack breathable film is a hot pack breathable film satisfying the following equations 5 and 6
4,000 ≤ P _air ≤ 20,000 [Equation 5]
10 ≤ | P _air | ≤ 20 [Equation 6]
(In Formula 5, Pair is the air permeability of the breathable film for hot packs (sec / 100cc), and in Formula 6, | P _air | is the deviation of air permeability of the breathable film for hot packs (%).) a) preparing a breathable compound by mixing a breathable film composition comprising a metallocene catalyst-based polyolefin resin, a linear low density polyethylene resin, a low density polyethylene resin, an inorganic filler and an additive;
b) extruding or coextruding the breathable compound to produce a single or multilayer unstretched film; And
c) uniaxially or biaxially stretching the unstretched film by 3.0 to 6.0 times to prepare a breathable film;
The metallocene catalyst-based polyolefin resin and linear low density polyethylene resin at the same time the method of producing a breathable film for hot packs satisfying the following formula 1 and formula 2.
0.915 ≤ D ≤ 0.940 [Equation 1]
2.0 ≤ MI ≤ 5.0 [Equation 2]
(In Equation 1, D is density (g / cm 3, 25 ° C.), and MI in Equation 2 is melt flow index (g / 10 min, 190 ° C., 2.16 kg). The method of claim 9,
The breathable film composition is 30 to 50% by weight of the metallocene catalyst-based polyolefin resin, 5 to 60% by weight of linear low density polyethylene resin, 3 to 8% by weight of low density polyethylene resin, 5 to 50% by weight of inorganic filler and 0.5 to 10% by weight of additive Method for producing a breathable film for a hot pack containing%. The method of claim 9,
When the multi-layer unstretched film is manufactured by coextrusion of the breathable compound in step b), the multilayer unstretched film is formed of an outer layer / middle layer / outer layer, and the extrusion ratio of the outer layer: middle layer: outer layer is 1: 4. 8: Method of producing a breathable film for hot packs formed of 1-3. delete