KR20040050585A - Composition for air permeable film of neutral pH without evolving moisture during processing - Google Patents

Abstract

PURPOSE: An air-permeable film composition of a neutral pH is provided, to prevent the generation of moisture during the process of a film. CONSTITUTION: The composition comprises 100 parts by weight of a polyolefin-based resin, 0.1-200 parts by weight of an inorganic filler and 0.1-200 parts by weight of an inorganic additive. An effluent obtained by dipping the film obtained from the composition in 10-50 times weight of neutral water (pH 6.5-7.5) for 5 min at a room temperature, has a pH of 5.0-9.0 or does not show dark purple or pink when 2-3 drops of a phenolphthalein indicator solution are added. Preferably the inorganic filler is one selected from the group consisting of calcium carbonate, barium sulfate or their mixture, or stearic acid-coated one, and has an average size of 0.7-5 micrometers; and the inorganic additive is selected from the group consisting of aluminosilicate, silica-alumina, silica, alumina and their mixtures.

Description

Composition for air permeable film of neutral pH without evolving moisture during processing

The present invention relates to a breathable film composition having a neutral pH that does not generate water during processing, and more particularly, to solve the problem caused by water frequently generated during processing by using an inorganic additive that is neutral in pH and strongly absorbs water. And a neutral pH, no skin irritation, a neutral pH, and no moisture generation during processing.

There are many methods for producing a breathable or porous film, but among them, the most economical and commercially available method is to mix inorganic fillers with polyolefin resins, and then form a film to form an interface between the resin and the filler through uniaxial or biaxial stretching. Separation is used to form fine pores.

For example, European Patent No. 0066672, European Patent No. 0307116, European Patent No. 0459142, and European Patent Publication No. 0779325 add a third material of fatty acids to polyolefin and various inorganic fillers to improve the softness of the film. A method of increasing or resolving an imbalance in physical properties in the longitudinal and transverse directions of a film is disclosed.

In addition, European Patent No. 0232060 describes a method for controlling the mechanical strength of a breathable film using a specific technique such as embossing on the post-processing of the film, and US Pat. No. 4,777,073 uses an embossing technique on the post-processing of the film. To increase moisture permeability and improve tear strength.

However, in order to manufacture a breathable film by using the method according to the aforementioned patent, an inorganic filler should be used, and these inorganic fillers are hydrophilic materials that absorb water in the air and have strong properties of absorbing moisture in the air. Will absorb moisture during storage. The moisture absorbed in this way evaporates during the processing of the breathable film, causing holes in the film, which is a frequent problem in the production of the breathable film, and is also an important problem that is a fatal defect in the quality of the film.

As a method of solving the problem of the occurrence of holes due to moisture, there is no method specifically disclosed as a patent, but the methods widely used in the actual industry include a method of drying a film raw material before film processing by installing a separate drying facility, The method of removing water by adding a small amount of calcium oxide as a dry purpose inorganic additive to a film raw material is widely performed.

However, in the case of installing and operating a separate drying facility as described above, additional equipment installation costs are incurred, and also in the drying performance, water contaminated on the surface of the film raw material grains can be removed. Moisture contained there is a limit that can not be removed there is a disadvantage that does not completely solve the moisture problem. In addition, when calcium oxide is used as an inorganic additive for drying purposes, it exhibits strong drying performance that removes even moisture inside the raw material granules, but has a very strong alkalinity with its own pH of about 12, resulting in final breathability even with a small amount of mixing. It has been reported that the pH of the film product is alkaline, causing skin irritation. In particular, related companies in Japan restrict the use of calcium oxide in all breathable products such as diapers and sanitary napkins, and in Korea, the pH is regulated to maintain neutral pH for sanitary napkin products.

On the other hand, the prior art cited above mentions that various inorganic materials can be simply used to make the breathable film, and the water problem during film processing and a solution therefor are not presented. The role of inorganic additives having a drying function in making breathable films has not been introduced.

In the present invention, as a result of extensive research in order to solve the problems described above, by using an inorganic additive having a pH of the neutral and the function of absorbing water to solve the water problem frequently occurring during the processing of the breathable film, When used in hygiene products such as disposable diapers or women's sanitary napkins, it was possible to obtain a pH-neutral, breathable film composition without skin irritation by pH, and the present invention was completed based thereon.

Accordingly, it is an object of the present invention to provide a breathable film composition in which the pH is neutral and no pores due to moisture are generated during processing.

The air permeable film composition of the present invention for achieving the above object is 100 parts by weight of polyolefin resin, 0.1 to 200 parts by weight of inorganic filler based on 100 parts by weight of the olefin resin, 0.1 to 200 parts by weight based on 100 parts by weight of the olefin resin The pH of the eluate eluted for 5 minutes at room temperature was immersed in neutral water (pH measurement value of 6.5-7.5) weighing 10-50 times with respect to the said film including the negative inorganic additive, and processed. It is characterized in that a pH of 5.0-9.0 is measured or dark violet / pink color is not present when 2-3 drops of the phenolphthalein indicator solution are added to the eluate.

Hereinafter, the present invention will be described in more detail.

As described above, according to the present invention, by using an inorganic additive that absorbs moisture strongly while maintaining a neutral pH, it solves a problem caused by moisture frequently generated during processing, and shows a neutral pH, so that the pH is neutral, without skin irritation. A breathable film composition is provided which does not generate moisture during processing.

As the polyolefin resin used in the present invention, one or two of low density polyethylene, linear low density polyethylene, high density polyethylene, α-olefin resin, homo polypropylene, random polypropylene, and impact polypropylene depending on the required physical properties of the final product The above resin can be mixed and used.

In addition, the inorganic filler used in the present invention is calcium carbonate, barium sulfate or a mixture thereof, the content is preferably 0.1 to 200 parts by weight based on 100 parts by weight of the polyolefin resin. In addition, the average particle size of the inorganic filler is preferably 0.7 to 5㎛, if the average particle size of the inorganic filler is less than 0.7㎛ there is a problem that can not exhibit the desired physical properties due to poor kneading during the manufacturing of breathable compound, 5㎛ If exceeded, the frequency of occurrence of holes during manufacturing the breathable film is increased, thereby increasing the occurrence of defects. On the other hand, the inorganic filler may be used as it is without coating, or may be used coated with stearic acid fatty acid.

As the inorganic additive usable in the present invention, one or a mixture of two or more of aluminosilicate, silica alumina, alumina and silica may be used, and the content thereof is preferably 0.1 to 200 parts by weight based on 100 parts by weight of the polyolefin resin. . At this time, if the content of the inorganic additive is less than 0.1 parts by weight, the effect of removing moisture is too low to solve the problem caused by moisture during processing, if more than 200 parts by weight becomes economical problem.

Meanwhile, the breathable film composition according to the present invention may optionally further include a lubricant. As the lubricant, calcium stearate or zinc stearate alone or both may be used simultaneously, and the content thereof is preferably 3 parts by weight or less based on 100 parts by weight of the polyolefin resin. At this time, when the content of the lubricant exceeds 3 parts by weight, a die build-up phenomenon occurs during molding of the breathable film, thereby reducing production efficiency.

In addition, the breathable film composition according to the present invention may optionally further comprise an antioxidant. As the antioxidant, phenol-based antioxidants or phosphoric acid-based antioxidants alone or both may be used at the same time, and the content thereof is preferably 3 parts by weight or less based on 100 parts by weight of the polyolefin resin. At this time, if the content of the antioxidant exceeds 3 parts by weight can not be expected to increase the antioxidant effect any more.

In addition, the breathable film composition according to the present invention may optionally further comprise titanium dioxide. The titanium dioxide is added to increase the whiteness or hiding power of the film, the content of which is preferably 10 parts by weight or less with respect to 100 parts by weight of the polyolefin resin. At this time, if the content of the titanium dioxide exceeds 10 parts by weight, economics become a problem.

In the breathable film composition according to the present invention comprising the above-mentioned components, the film formed after processing is immersed in neutral water (pH measurement value of 6.5-7.5) weighing 10-50 times with respect to the film and eluted at room temperature for 5 minutes. The pH of the eluate is pH 5.0-9.0 when measured with a pH meter, or when the solution is given 2-3 drops of phenolphthalein indicator solution, the dark purple / pink color does not appear. It is characterized by no occurrence.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

This example relates to a breathable film with a neutral pH and no water generation problems during processing.

80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.99, copolymerization monomer = octene) and a low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. ) 20 parts by weight, 100 parts by weight of calcium carbonate (average particle 1.4 μm) surface treated with stearic acid, 1 part by weight of antioxidant (Kolon Emulsification, Grade name = KB9112C), 0.5 parts by weight of zinc stearate and calcium stearate (Dubon Chemical) , And 2 parts by weight of titanium dioxide were melt mixed and extruded to prepare a breathable compound in pellet form.

In addition, 100 parts by weight of low-density polyethylene (Hanhwa, MI = 5.3, density = 0.923) and 100 parts by weight of aluminosilicate (pH = 9.0, average particle 3.0 µm) were melted using a twin screw extruder whose extrusion temperature was maintained at an average temperature of 190 ° C. Mixing and extruding to prepare aluminosilicate masterbatch in pellet form

In order to observe the problem caused by the moisture absorption of the manufactured breathable compound, after leaving for 6 hours at a temperature of 30 ℃, relative humidity 90%, 100 parts by weight of the breathable compound mixed with 1 part by weight of the aluminosilicate master batch Then, the mixture was introduced into a T-die film forming machine (screw diameter 130 mm) to prepare a film at an extrusion temperature of 200 to 250 ° C., and uniaxially stretched twice in the machine direction to prepare a breathable film having a basis weight of 40 g / m 2. It was. The characteristics of the breathable film formed therefrom were evaluated as follows, and the results are shown in Table 1 below.

<Evaluation Method>

△ Water pollution time before film processing: The time that moisture-permeable moisture was absorbed by leaving the air permeable compound pellet at a temperature of 30 ° C. and a relative humidity of 90%.

△ Moisture hole generation: After cutting the manufactured air permeable film into A4 paper size, observe 3 sheets, and if there is one smooth oval hole without foreign matter, it is determined that moisture hole has occurred.

△ pH measurement value: After dipping about 2.0g of the film cut to 7.5cm in width and 10 times in neutral water (pH measurement value is 6.5-7.5), eluate eluted for 5 minutes while slowly shaking at room temperature was measured by pH measurement system. (Orion Research Inc. USA, Model 420A).

Phenolphthalein Indicator Discoloration: After dipping about 2.0 g of a film cut to 7.5 cm in width and 10 times in neutral water (pH measuring value of 6.5 to 7.5), the eluate eluted for 5 minutes while slowly shaking at room temperature was tested. Pour at half height. Phenolphthalein indicator solution (solution made by adding 100 ml of 95% ethanol to 1 g of phenolphthalein reagent for 95% purity reagent, or 50 ml of 95% ethanol and 50 ml of neutral water to 1 g of phenolphthalein reagent for purity 95% reagent) Immediately after dropping 2-3 drops of), compare the overall color change of the test tube solution with neutral water.

Example 2

This example relates to a breathable film with a neutral pH and no water generation problems during processing.

80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.99, copolymerization monomer = octene) and a low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. ) 20 parts by weight, 100 parts by weight of calcium carbonate (average particle 1.4 μm) surface treated with stearic acid, 1 part by weight of antioxidant (Kolon Emulsification, Grade name = KB9112C), 0.5 parts by weight of zinc stearate and calcium stearate (Dubon Chemical) , And 2 parts by weight of titanium dioxide were melt mixed and extruded to prepare a breathable compound in pellet form.

In addition, 100 parts by weight of low-density polyethylene (Hanhwa, MI = 5.3, density = 0.923) and 100 parts by weight of aluminosilicate (pH = 9.5, average particle 2.5 µm) were melted using a twin screw extruder whose extrusion temperature was maintained at an average of 190 ° C. Mixing and extruding to prepare aluminosilicate masterbatch in pellet form

In order to observe the problem due to the moisture absorption of the manufactured breathable compound, after leaving for 12 hours at a temperature of 30 ℃, relative humidity 90%, 80 parts by weight of the aluminosilicate masterbatch 20 parts by weight of the aerated compound Thereafter, the mixture was introduced into a T-die film forming machine (screw diameter 130 mm) to prepare a film at an extrusion temperature of 200 to 250 ° C., and uniaxially stretching it in the machine direction to prepare a breathable film having a basis weight of 55 g / m 2. It was. The characteristics of the breathable film formed therefrom were evaluated according to the method shown in Example 1, and the results are shown in Table 1 below.

Example 3

This example relates to a breathable film with a neutral pH and no water generation problems during processing.

80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.99, copolymerization monomer = octene) and a low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. 20 parts by weight, and 100 parts by weight of calcium carbonate (average particle 1.4 μm) surface-treated with stearic acid were melt mixed and extruded to prepare a breathable compound in pellet form.

In addition, 80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.919, copolymerization monomer = octene) and low density polyethylene (Hanhwa, MI = 5.3, density) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. = 0.923) 20 parts by weight and 100 parts by weight of aluminosilicate (pH = 8.5, 2.0 µm in average particle size) were melt mixed and extruded to prepare an aluminosilicate masterbatch in pellet form.

In order to observe the problem caused by the moisture absorption of the manufactured breathable compound, after leaving for 24 hours at a temperature of 30 ℃, relative humidity 90%, 40 parts by weight of the aluminosilicate master batch mixed with 60 parts by weight of the breathable compound Thereafter, the mixture was introduced into a T-die film forming machine (screw diameter 130 mm) to prepare a film at an extrusion temperature of 200 to 250 ° C., which was uniaxially stretched twice in the machine direction to prepare a breathable film having a basis weight of 25 g / m 2. It was. The characteristics of the breathable film formed therefrom were evaluated according to the method shown in Example 1, and the results are shown in Table 1 below.

Example 4

This example relates to a breathable film with a neutral pH and no water generation problems during processing.

80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.99, copolymerization monomer = octene) and a low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. ) 20 parts by weight, 100 parts by weight of calcium carbonate (average particle 1.4 μm) surface-treated with stearic acid, 1 part by weight of aluminosilicate (pH = 9.0, average particle 3.0 μm), antioxidant (colon emulsion, Grade name = KB9112C) 1 part by weight, 0.5 parts by weight of zinc stearate and calcium stearate (Dubon Chemical), respectively, and 2 parts by weight of titanium dioxide were melt mixed and extruded to prepare a breathable compound in pellet form.

In order to observe the problem caused by the moisture absorption of the manufactured breathable compound, after leaving for 6 hours at a temperature of 30 ℃, relative humidity 90%, the breathable compound is put into a T-die film forming machine (screw diameter 130mm) A film was prepared at an extrusion temperature of 200 to 250 ° C., and then uniaxially stretched twice in the machine direction to prepare a breathable film having a basis weight of 40 g / m 2. The characteristics of the breathable film formed therefrom were evaluated according to the method shown in Example 1, and the results are shown in Table 1 below.

Comparative Example 1

In this comparative example, in order to grasp the moisture-absorbing properties of the breathable compound containing an excessive amount of the inorganic filler and problems in processing the breathable film, a breathable film was not mixed with the third inorganic additive in a comparative experiment.

80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.99, copolymerization monomer = octene) and a low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. 20 parts by weight and 100 parts by weight of calcium carbonate (average particles 1.4 μm) surface-treated with stearic acid were melt mixed and extruded to prepare pellets.

In order to observe the problem caused by the moisture absorption of the manufactured breathable compound, after leaving for 6 hours at a temperature of 30 ℃, relative humidity 90%, this raw material is put into a T-die film forming machine (screw diameter 130mm) and extruded A film was prepared at a temperature of 200 to 250 ° C., which was uniaxially stretched twice in the machine direction to produce a breathable film having a basis weight of 40 g / m 2. The characteristics of the breathable film formed therefrom were evaluated according to the method shown in Example 1, and the results are shown in Table 1 below.

Comparative Example 2

In the present comparative example, the experiment was carried out as follows to determine the problem that occurs when adding calcium oxide commonly used as additives for drying purposes in the industry in the production of breathable film.

80 parts by weight of linear low density polyethylene (SK Co., Ltd., MI = 2.0, density = 0.99, copolymerization monomer = octene) and a low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) using a twin screw extruder whose extrusion temperature is maintained at an average temperature of 190 ° C. 20 parts by weight, and 100 parts by weight of calcium carbonate (average particle 1.4 μm) surface-treated with stearic acid were melt mixed and extruded to prepare a breathable compound in pellet form.

In addition, 100 parts by weight of low density polyethylene (Hanhwa, MI = 5.3, density = 0.923) and 100 parts by weight of calcium oxide (average particle 3.0 μm) were melt mixed and extruded using a twin screw extruder having an extrusion temperature of 190 ° C. on average. Calcium oxide masterbatch was prepared in the form.

In order to observe the problem caused by the moisture absorption of the manufactured breathable compound, after leaving for 6 hours at a temperature of 30 ℃, 90% relative humidity, after mixing 1 part by weight of the calcium oxide masterbatch to 100 parts by weight of the breathable compound The mixture was introduced into a T-die film forming machine (screw diameter 130 mm) to prepare a film at an extrusion temperature of 200 to 250 ° C., which was uniaxially stretched twice in the machine direction to prepare a breathable film having a basis weight of 40 g / m 2. . The characteristics of the breathable film formed therefrom were evaluated according to the method shown in Example 1, and the results are shown in Table 1 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Water pollution time before film processing 6 6 6 12 24 6 Water hole Occur none none none none none pH measurement 7.5 9.3 7.9 8.5 7.8 8.0 Phenolic phthalate solution color change Colorless Dark purple Colorless Light purple Colorless Light purple

As shown in Table 1, water holes are generated in the film formed by using the air-permeable compound containing the inorganic filler in excess, and is formed by adding calcium oxide, which is commonly used as an additive for drying purposes in the industry in the production of the air-permeable film. In the case of the film was out of the range of the neutral pH, the film formed using the breathable film composition according to the present invention was found to have a neutral pH and no hole generation due to moisture during processing.

As described above, according to the present invention, using an inorganic additive that is neutral in pH and strongly absorbs moisture, it solves the water pore problem caused by moisture frequently generated during processing, and exhibits a neutral pH to prevent skin irritation. Can be provided.

Claims (7)

100 parts by weight of polyolefin resin, 0.1 to 200 parts by weight of an inorganic filler based on 100 parts by weight of the olefin resin, 0.1 to 200 parts by weight of an inorganic additive based on 100 parts by weight of the olefin resin, the film formed after processing PH of the eluate eluted in neutral water (pH measurement value of 6.5-7.5) weighing 10-50 times with respect to the film and eluted at room temperature for 5 minutes is measured to pH pH 5.0-9.0, or A neutral pH breathable film composition having no water generation during processing, characterized in that dark purple / pink color does not appear when 2-3 drops of a phenolphthalein indicator solution is added to the eluate. The method of claim 1, wherein the polyolefin resin is selected from the group consisting of low density polyethylene, linear low density polyethylene, high density polyethylene, α-olefin resin, homo polypropylene, random polypropylene, impact polypropylene and mixtures thereof Breathable film composition. According to claim 1, wherein the inorganic filler calcium carbonate, barium sulfate or a mixture thereof is used as it is, or coated with a stearic acid-based fatty acid, and the average particle size of the inorganic filler is characterized in that 0.7 ~ 5㎛ Breathable film composition. The breathable film composition of claim 1, wherein the inorganic additive is selected from the group consisting of aluminosilicate, silica alumina, silica, alumina, and mixtures thereof. According to claim 1, wherein the composition further comprises a lubricant selected from the group consisting of calcium stearate, zinc stearate and mixtures thereof, the amount of the lubricant is 3 parts by weight or less based on 100 parts by weight of the polyolefin resin. Breathable film composition. The method of claim 1, wherein the composition further comprises an antioxidant selected from the group consisting of phenolic antioxidants, phosphoric acid antioxidants and mixtures thereof, the amount of the antioxidant is 3 to 100 parts by weight of the polyolefin resin It is below a weight part, The breathable film composition characterized by the above-mentioned. The breathable film composition of claim 1, wherein the composition further comprises 10 parts by weight or less of titanium dioxide based on 100 parts by weight of the polyolefin resin.