KR950014918B1 - Degradable and ventilative film and method for manufacturing the same - Google Patents

Abstract

mixing 100 wt.pts polyolefin based film, 50-500 wt.pts one or more inorganic filler selected from calcium carbonate, barium sulfate, talc, silica, diatom earth or magnesium carbonate, 2-50 wt.pts biodegradable component and/or 0.005-5 wt.pts photo-degradable component; then forming to film; and drawing in temp. range between Tg and melting point, pref. 40-150 deg.C and of 1.5-36 drawing ratio by area. The obtd. film has good appearance and touchiness, strength, moisture permeability, and biodegrable and photodegradable properties.

Description

Degradable breathable film and its manufacturing method

The present invention relates to a breathable film having a degradable property and a method of manufacturing the same, more particularly, having a good appearance and feel, excellent strength and proper moisture permeability, and having properties of being readily decomposed by light or microorganisms after use. A polyolefin breathable film and a method for producing the same.

Breathable film is used for various purposes such as disposable diapers, waterproof clothing, packaging materials, sanitary materials. Among them, disposable diapers, which are being used in large quantities recently, consist of a water-permeable top sheet, an absorbent body and a water-impermeable back sheet, which are used to prevent the skin from breathing and crushing. It provides air permeability, and such a back sheet is made of thermoplastic resin as an essential component, and a film having a low surface glossiness in terms of appearance and feel of a diaper is used. As such a method of reducing the surface glossiness of the film, a method of forming protrusions and depressions on the surface of the film is used.

Conventionally, attempts have been made to obtain a breathable film by blending an inorganic or organic filler with a polyolefin resin at a specific ratio, and then stretching the film obtained by melt coating by a known method (for example, Japanese Patent Application Laid-Open No. 57). -203520, So 58-15538, So 60-12940, So 60-199037).

By the way, the air permeable film obtained by the said method has a high surface glossiness, there is a plastic feeling, and an external appearance is bad, but there is little surface glossiness, but there is a problem that a softness falls and a touch falls.

In addition, the disposable plastic products, including disposable diapers, are discarded in the natural world after use and contaminate the environment without being decomposed, which is a social problem, and the countermeasures are urgently required.

The present inventors have intensively solved the above problems, that is, excellent results in flexibility, surface gloss and moisture permeability, and at the same time have excellent degradability to obtain a breathable film which does not cause environmental pollution in the natural world after use. It came to invention.

SUMMARY OF THE INVENTION An object of the present invention is a breathable film obtained by stretching a composition containing a polyolefin resin, a filler and a decomposable third component, wherein the decomposable third component comprises a particulate biodegradable polymer or a photodegradation accelerator alone or in a mixture of two or more thereof. It is to provide a breathable film having a decomposable, characterized in that the use and a method for producing the same.

The present invention is characterized by providing a decomposable breathable film obtained by stretching a composition containing a polyolefin resin, an inorganic or organic filler and a biodegradable and / or photodegradable third component, and a method for producing the same. More specifically, the inorganic or organic filler is added in an amount of 50-500 parts by weight based on 100 parts by weight of polyolefin resin, and the particulate starch or derivative thereof is 2-50 parts by weight based on 100 parts by weight of polyolefin resin as the third biodegradable component. It is obtained by extending | stretching the composition to add.

This invention also includes the thing obtained by extending | stretching the composition which the well-known photolysis promoter added as 0.005-5 weight part with respect to 100 weight part of polyolefin resin as a photodegradable 3rd component individually or in mixture of 2 or more types.

This invention also includes the thing obtained by extending | stretching the composition to which particulate starch or its derivative (s) and a photolysis promoter are added simultaneously as a degradable 3rd component.

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

As the polyolefin resin in the present invention, high density polyethylene, medium density polyethylene, linear low density polyethylene, and low density polyethylene may be used alone or as a mixture of two or more kinds. In terms of mechanical properties, linear low density polyethylene is preferable, and the polyethylene is melted. The Melt Index is preferably 0.01-10 g / 10 min (measured at 190 ° C. and 2.16 kg according to ASTM D 1238-70) and a density of 0.96 g / cm 2 (according to ASTM D 792) or less.

Linear low density polyethylene is a copolymer of ethylene and an alpha olefin, and it is possible to use butene, hexene-1, octene-1, 4-methylpentene-1, etc. as the alpha olefin.

When the melt index of the linear low density polyethylene is out of the above range, the melt processability, the moldability, and the film physical properties are lowered, and when the density exceeds the above range, the film becomes hard and the appearance and feel are bad.

In addition, crystalline polypropylene is also used. As the crystalline polypropylene, a propylene homopolymer or a copolymer of propylene with another α-olefin is used alone or as a mixture of two or more thereof. It is possible to mix | blend these polyolefin resin with additives, such as a heat stabilizer, a ultraviolet absorber, an antistatic agent, a pigment, and a fluorescent agent, according to a well-known method.

As the filler, inorganic fillers and organic fillers are used, and as inorganic fillers, calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, calcium chloride, calcium sulfate, barium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide, titanium oxide, alumina , Mica, asbestos powder, glass powder, zeolite, clay silicate and the like are used, and calcium carbonate, talc, clay, silica, diatomaceous earth, barium sulfate and the like are particularly preferable. As the organic filler, cellulose-based powders such as wood powder and pulp are used. These are used individually or in mixture of 2 or more types.

On the other hand, surface treatment of the inorganic filler with a fatty acid or a metal salt thereof, silicone, silica, resin acid, or the like is more preferable because it improves dispersibility with the resin and improves stretchability.

As average particle diameter of a filler, 30 micrometers or less are preferable, 10 micrometers or less are more preferable, and 5 micrometers or less are optimal. If the particle size is too large, the pore density of the stretched product becomes bad.

The amount of the filler used is appropriately 50-500 parts by weight, preferably 100-400 parts by weight, based on 100 parts by weight of the polyolefin resin. If this amount is less than 50 parts by weight, air permeability cannot be sufficiently obtained. If the amount is more than 500 parts by weight, the rigidity of the film increases and stretching is not easily achieved, and the amount of ventilation is reduced.

In the present invention, the third biodegradable component is starch or a derivative thereof. Examples include corn starch, waxy corn starch, high amylose starch, wheat starch, rice starch, potato starch, sorghum starch, acid starch, oxidized starch, crosslinked starch, alpha starch, ester starch, hydroxyethyl starch, hydroxypropyl Starch and the like.

As the biodegradable third component, polyalkanoates, polycaprolactones, polylactides, polyglycolides, polyalcohols such as known aliphatic polyesters such as polyhydroxybutylate and poly (hydroxybutylate-co-valorate) Although hexamethylene nitrite, polyethylene nitrite, etc. may be used, they are too compatible with polyolefins and thus do not act as particle sources, and thus do not play a significant role in imparting air permeability in the stretching process. It has been found to advantageously act as a particle source to provide excellent breathability and at the same time to provide biodegradability.

In addition, due to the inherent color of the particulate starch or its derivatives and the surface characteristics of the particles, the final stretched film has a low surface gloss and has an excellent appearance in an elegant atmosphere, and is more than when only inorganic and organic additives are added alone. It was found to exhibit a much more flexible touch.

However, the aliphatic polyester may be partially mixed in an appropriate amount for the purpose of slightly improving biodegradability.

The average particle diameter of the particulate starch or derivatives thereof is suitably in the range of 0.5 to 50 µ, preferably in the range of 1 to 20 µ, and more preferably in the range of 2 to 10 µ. Although the particle size is slightly larger than that of the inorganic filler, it is relatively compatible and shows good breathability without deterioration of mechanical properties. If the particle size is too large, the pore density after stretching is bad, and if the particle size is too small, the pore formation is not good, and the desired breathable film cannot be obtained.

The amount of the finely divided starch or derivatives thereof is appropriately 2-50 parts by weight with respect to 100 parts by weight of the polyolefin resin, and preferably 10-30 parts by weight. If the amount is less than 2 parts by weight, the biodegradability cannot be sufficiently exhibited. If the amount is more than 50 parts by weight, the film may break due to lack of compatibility between the polyolefin resin and the starch or its derivatives. Mechanical strength is extremely poor and good breathability is not expected.

In the present invention, a photolysis accelerator may be used as the degradable third component. Specific photolysis additives include USP 3,797,690, USP 3,860,538, USP 4,121,025, USP 4,461,853, USP 3,676,401, USP 2,495,206, USP 3,083,184 Japanese Patent Application Publication Nos. 47-6282, Small 47-9588, Small 47-10838, Small 47-21440, Small 48-14738, SO 48-14740, SO 48-14741, SO 48-17841, SO 48-17842, SO 48-43748, SO 50-21079, SO 50-34340 already known as described in other publications. , Condensates of aldol and α-naphthylamine, metal dialkyl-dithiocarbamates, salicylate, α-mercaptobenzothioazole, copper acetate, zinc, such as acetylacetone, cobalt diethyl-dithiocarbamate Fatty acid metal salts such as stearate, thiodipropionic acid, iron acetylacetonate, metal acetylacetonates such as cobalt acetyl acetonate, p-benzoquinone, α-naphthoquinone, anthraquinone and derivatives thereof, propiophenone, benzophenone and the like Derivatives and the like.

Also, in order to further enhance the photodegradation effect, known polyolefin-based photodegradable resins such as polyolefin-based resins or photo-degradation accelerators, such as vinyl-ketone copolymers (ECOLYTE ATLANTIC, product name: ECOLYTE), and ethylene-carbon monoxide copolymers (UNION CARBIDE) , Product Name: DXM-439) can be used.

Photodegradable breathable polyolefin type film can be manufactured by extending | stretching the mixture in which the filler and the said photolysis promoter were added individually or in mixture of 2 or more types to polyolefin resin.

The addition amount of a photolysis promoter is suitable for 0.005-5 weight part with respect to 100 weight part of polyolefin resins, and 0.1-3 weight part is preferable. If the amount is less than 0.005 parts by weight, it is difficult to expect good photodegradation properties. If the amount is more than 5 parts by weight, it serves as a kind of plasticizer, leading to a decrease in the mechanical properties of the film, and a disadvantage of inferior economic efficiency due to the high cost of the photodegradation accelerator. have.

On the other hand, the photodegradation accelerators of the particulate biodegradable polymer, that is, starch or derivatives thereof, which are the decomposable third component in the present invention may be used alone, respectively, but when used together, they exhibit better degradability and breathability. When the air-permeable film is discarded after use, it is usually exposed to light to some extent, and photolysis proceeds, but it is gradually buried in the ground, so that the photodegradation property cannot be effectively exhibited. It is because it is more preferable to advance and to improve a decomposability.

Hereinafter, the manufacturing method of the decomposable breathable film of this invention is demonstrated in detail.

A proper amount of filler and the degradable third component are added to a polyolefin resin and mixed in a conventional blender or mixer. As the mixer, a drum, a dumbler type mixer, a ribbon blender, a Henschel mixer, a super mixer, or the like may be used. A high speed stirring mixer such as a Henschel mixer is preferable.

Next, the mixture is kneaded, which is appropriately carried out by a conventionally known apparatus such as a conventional screw extruder, a twin screw extruder, a mixing roll, a balbaric mixer, a twin screw kneader, and the like. Subsequently, the kneaded resin composition is pelletized, and the pellet is molded according to a conventional film forming apparatus and a molding method, and in-flation molding by a circular die, T-die extrusion molding by a T-die, etc. is appropriately performed. It may be adopted. It is also possible to carry out direct extrusion film forming without pelletizing at this time.

The molded film was then subjected to 1.2 in terms of mechanical properties, breathability, appearance, feel, etc. at a temperature between the glass transition point and the melting point or less, preferably between 40 ° C and 150 ° C, more preferably between 50 ° C and 120 ° C. In the range of times -6.0 times, preferably in the range of 1.5 times-4.0 times in the running direction. In this case, when the temperature is lower than 40 ° C, the film is ruptured before the elongation exceeds the yield point, and thus the film cannot be stretched. When the temperature exceeds the melting point, the tube is satisfactory at the time of stretching in the running direction due to the flow of the molecular chain. It is impossible to gain skills. In particular, when the temperature exceeds 150 ° C., starch or its derivatives are partially decomposed to cause yellowing. In addition, when the draw ratio is less than 1.2 times, sufficient ventilation is not obtained, the film is also hard, and the touch is also bad, and the stretching nonuniformity occurs, so that the stretching nonuniformity remains even after the stretching in the width direction, and thus the commodity value decreases. In addition, when the draw ratio is more than 6 times, a cutting phenomenon occurs during stretching and a film cannot be stably obtained. The running direction stretched film is then widthwise stretched under the conditions and draw ratios of the above temperature range to obtain a biaxially stretched breathable film.

Moreover, it is also possible to carry out only uniaxial stretching without biaxial stretching as mentioned above. In this case, the total area stretching ratio is in the range of 1.5 times to 36 times. If the area stretching ratio is less than 1.5 times, sufficient air permeability cannot be obtained, and the film is hard and the touch is degraded. When the area stretching ratio is more than 36 times, breathability is obtained, but surface glossiness is increased, appearance is deteriorated, and rupture occurs during stretching. The workability is reduced.

In order to improve the dimensional stability, the film after extending | stretching may heat-fix, and you may perform an enbossing process in order to improve an external appearance and a touch.

As described above, the film obtained by the present invention has a high porosity, is flexible, has a low surface glossiness, which not only has a good appearance but also has a good feel, and also has excellent mechanical properties, and is decomposed by light or microorganisms in nature. It is a groundbreaking one that does not cause environmental pollution.

The present invention will be described in more detail with reference to the following Examples, which are not intended to limit the present invention. In the Example, the measurement of physical properties is by the following method.

EXAMPLE

(1) basis weight (g / ㎠)

The test piece of 100 mm x 100 mm size was extract | collected in the arbitrary place of a film, the weight was measured by the balance, and it converted into the film weight per 1m <2>.

(2) tensile properties

In accordance with JIS P. 8113, the strength (kg / cm 2) and elongation (%) at the time of fracture of the sample were measured in the traveling direction (MD) and in the direction perpendicular to the traveling direction (TD) (sample size: 100 mm length). × 25mm width, tensile speed: 200mm / min, measurement temperature: 23 ± 1 ℃).

(3) tear strength (g)

It measured in accordance with JIS K6772 (measurement temperature: 23 ± 1 ℃, tensile speed: 200 mm / min).

(4) Water vapor permeability (g / ㎡, 24h)

It measured according to ASTM E 96-63 (temperature: 37.8 degreeC, humidity 90% R.H).

(5) Glossiness (%)

It measured in accordance with JIS K 8741 (incidence angle, reflection angle: 60 °).

(6) Yellow Index YI

According to JIS K 7013, 10 films were piled up and used as the sample for a measurement, and it measured according to the reflection method.

(7) appearance

It measured visually ((◎: very good, (circle): good, (triangle | delta): slightly bad, x: bad).

(8) touch

It was directly touched by hand and measured as a touch (◎: very good, (circle): good, (triangle | delta): slightly bad, x: bad).

(9) extensibility

It was measured visually (A: good, B: extending | stretching nonuniformity generation, C: extending | stretching cleavage occurrence).

(10) biodegradable

After cutting the sample to a certain size, using agar as a medium, aspergillus niger, penicillium funiculosum, trichoderma sp and trichoderma sp. Biodegradation characteristics were measured by spraying a mixed mycelium suspension of Lularia Pullulans (1) and recording the degree of mold cover on the sample after 1-4 weeks.

0%: 0, 10% or less: 1, 10-30%: 2, 30-60%: 3, 60-100%: 4

(11) photodegradable

After cutting the sample to a certain size, it was mounted in a weather resistance tester (Ci65A, ATLAS Co., Ltd.), left under Xenon arc, and then inspected for a predetermined time to measure the time until it was easily crushed into pieces.

Example 1-8

With respect to 100 parts by weight of linear low density polyethylene (LLDPE) having a melt index of 2.0 g / 10 minutes and a density of 0.920 g / cm 3, calcium carbonate (average particle size 1.0 μ) or barium sulfate (average particle size 2.0 μ) was decomposed as a filler. As the third component, corn starch (average particle diameter 2.5 mu) or oxidized starch (average particle diameter 2.0 mu) was added in the amounts shown in Table 1, mixed in a Henschel mixer, and the mixture was kneaded with a twin screw kneader, and then pellets It was done. The pellets were melt film-formed using the T-die extruder. Then, it extended | stretched under the extending | stretching conditions shown in Table 1, and obtained the decomposable breathable film of 35 g / m <2> of basis weights. The physical properties of the obtained film are shown in Table 1. It can be seen that a film having excellent mechanical properties and breathability as well as excellent biodegradability can be obtained.

Example 9-15

As shown in Table 2, a breathable film was prepared by adding a photolysis accelerator as a degradable third component. Photodegradation accelerators used herein are iron acetylacetonate, cobalt acetylacetonate, copper stearate and vinyl-ketone copolymers (ECOLYTE # 5020 from ECOLYTE ATLANTIC). Other implementation methods are the same as in Example 1-8. The physical properties of the obtained film are shown in Table 2. It can be seen that a film having excellent mechanical properties and breathability as well as excellent photodegradability can be obtained.

Example 16-18

As shown in Table 3, except that the starch used in Example 1-8 and the photolysis accelerator used in Example 9-15 were mixed and added as the decomposable third component, the same method as in Example 1-15 was carried out for the breathability. A film was obtained. The physical properties of the obtained film are shown in Table 3. It can be seen that a film having excellent degradability can be obtained by using a combination of mechanical properties and breathability as well as bio / photodegradability.

Example 19-21

High density polyethylene (HDPE, melt index: 2.0g / 10min, density: 0.950g / cm3), low density polyethylene (LDPE, melt index: 2.0g / 10min, density: 0.923g / cm3) with polyolefin resin and Examples Except for using the linear low density polyethylene used in 1-18 Example 1-18 was carried out in the same manner to obtain a breathable film excellent in degradability. The physical properties of the obtained film are shown in Table 4.

[Comparative Example 1-6]

The physical properties of the films according to various conditions as shown in Table 5 were measured without adding the degradable third component, and in Comparative Example 3-4, the films according to the various conditions were prepared without adding the filler and the physical properties thereof were measured. . In Comparative Example 5-6, the physical properties of the film obtained when the excess third component was added were measured. Other manufacturing methods are the same as in the examples. The obtained results are shown in Table 5.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

Claims (8)

50 to 500 parts by weight of at least one inorganic filler selected from 100 parts by weight of polyolefin resin, calcium carbonate, barium sulfate, talc, silica, diatomaceous earth and magnesium carbonate, biodegradable, 2-50 parts by weight of the third component and / or photodegradable Degradable breathable film consisting of 0.005-5 parts by weight of a third component. The degradable breathable film according to claim 1, wherein the third biodegradable component is particulate starch or a derivative thereof. The method of claim 2, wherein the particulate starch or derivatives thereof are corn starch, waxy corn starch, high amylose starch, wheat starch, rice starch, potato starch, sorghum starch, acid starch, oxidized starch, crosslinked starch, alpha starch, ester. A degradable breathable film, characterized in that it is selected from the group consisting of starch, hydroxy ethyl starch and hydroxy propyl starch. The photodegradable third component is a condensate of an aldol with α-naphthylamine, acetylacetone, metaldialkyl-dithiocarbamate, salicyaldehyde, α-mercaptobenzothioazole, fatty acid metal salt. , Thiodipropionic acid, metal acetylacetonate, p-benzoquinone, α-naphthoquinone, anthraquinone and derivatives thereof, propiophenone, benzophenone and derivatives thereof, vinyl-ketone copolymers, ethylene-carbon monoxide copolymers Degradable breathable film, characterized in that selected from the group consisting of. The decomposable breathable film according to claim 1, wherein the polyolefin resin is a high density polyethylene, a medium density polyethylene, a linear low density polyethylene, a low density polyethylene, or a crystalline polypropylene, which is used alone or in a mixture of two or more thereof. 100 parts by weight of polyolefin resin, 50-500 parts by weight of at least one inorganic filler selected from calcium carbonate, barium sulfate, talc, silica, diatomaceous earth, magnesium carbonate, 2-50 parts by weight of a biodegradable third component, and / or a photodegradable agent 0.005-5 parts by weight of three components are mixed and kneaded, and then the film is molded and stretched at a temperature above the glass transition point or below the melting point. The method of claim 6, wherein the temperature is 40-150 ° C. 8. The production method according to claim 6, wherein the total area draw ratio of the film is 1.5-36 times uniaxially or biaxially.