JP2001293827A - Laminated porous film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated porous film excellent in air permeability, flexibility, barrier propertries or the like. SOLUTION: The laminated porous film, which is obtained by molding a composition containing a polyolefin resin, a filler and a third component in a molten state to form a film and stretching the film, consists of an X-layer containing an amide compound as the third component and a Y-layer containing at least one of an ester compound, a hydrocarbon polymer having a side chain, a silicone polymer and mineral oil as the third component and a thickness ratio of the X-layer and the Y-layer is 1/10-10/1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous film used for sanitary materials, medical materials, architectural materials and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a porous film, a method in which a raw material composition containing a polyolefin resin and a filler is melt-molded to generate a film and a void is generally used. When used as a material for disposable diapers and sanitary products, it is particularly required that it does not leak human urine, blood, etc. and that it can only pass moisture. Moreover, it is difficult to obtain a material having a supple feel from a raw material composition comprising only a polyolefin resin and a filler. Therefore, in order to improve the performance of the porous film, many methods have been proposed in which a raw material composition is blended with a third component other than a polyolefin resin and a filler. As the third component, fatty acid amide, liquid paraffin, sorbitan fatty acid ester (JP-A-62-250038), ethylenebisstearic acid amide, methylenebisstearic acid amide, methylenebisoleic acid amide (JP-A-11-158305)
), Diesters of dialkanolamide and an aliphatic dibasic acid (JP-A-11-35715), liquid polybutadiene, liquid polybutene, hydroxy-terminated liquid polybutadiene (JP-A-58-15538), liquid polyisoprene (JP-A-58-15538). No. 58-149925).

[0003]

There are other problems with the porous film. For example, in use, it is necessary that the adhesive tape such as a fastening tape has good adhesion to the film. When a porous film with poor adhesion is used as a backsheet for disposable diapers, it is difficult to fix the disposable diaper with fastening tape when attaching it to the human body, which may cause leakage of human urine etc. Become. Furthermore, at that time, there is a problem that the components contained in the adhesive tape migrate to the porous film, the shielding property is impaired, and the opaque part is transparent and the inside can be seen through. However, with the above-mentioned known method, there has been no method capable of simultaneously solving the above-mentioned problems of adhesiveness and shielding while maintaining sufficient air permeability.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present inventors have maintained the air permeability at the same level or higher as that of conventional products.
As a result of intensive studies to provide a porous film that has excellent adhesion and shielding properties, and is flexible and has a good texture, a film layer using a raw material composition containing a specific third component is combined. It has been found that a porous film having desired physical properties can be obtained by using such a laminated film, and the present invention has been achieved. That is, the present invention is a porous film obtained by melt-forming a composition containing a polyolefin resin, a filler and a third component to form a film, and then subjecting the film to a stretching treatment, wherein the third component is X containing an amide compound
And a Y layer containing at least one of an ester compound, a hydrocarbon polymer having a side chain, a silicone polymer, and a mineral oil as the third component. The thickness ratio of the X layer and the Y layer is 1/10 to 10: 10/1, which is a laminated porous film.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As the polyolefin resin used in the present invention, ethylene, propylene, and those mainly containing a monoolefin polymer and copolymer such as butene, for example, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene , Ethylene propylene random or block copolymer, polybutene, ethylene vinyl acetate copolymer and mixtures thereof. Among them, linear low-density polyethylene is preferred because it is flexible and tough.

The polyolefin resin used in the present invention is
And particularly preferred are linear density polyethylene and branched low-density polyethylene.
It is a mixture of high density polyethylene. Linear low density polyethylene
Ren is an α-olefin having a molecular skeleton having 3 to 8 carbon atoms.
It is a copolymer of ethylene and ethylene. Linear low density polyethylene
Len has a density of 0.910 to 0.940 g / cm
^ThreeHaving a melt index of 0.5 to 5 g / 10 minutes
Is preferred. Density 0.910g / cm^ThreeLess than
Uniform stretchability decreases, 0.940 g / cm^ThreeExceeds
The softness of the stretched film is impaired. Also, Mel Toy
When the index is less than 0.5 g / 10 minutes, the film
A film with a uniform thickness due to abnormal flow during extrusion
It is difficult to obtain.
Elongation deteriorates.

[0007] The branched low-density polyethylene is obtained by polymerizing ethylene by a known high-pressure method, and has a melt index of 0.1 to 2 g / 10 min.
Those having a density of 0.915 to 0.925 g / cm ³ are preferred. When the melt index is less than 0.1 g / 10 minutes, the mixing with the former linear low-density polyethylene is poor, and when it exceeds 2 g / 10 minutes, a film having a uniform thickness cannot be obtained. If the density exceeds 0.925, it becomes difficult to obtain a film having a uniform thickness.

[0008] The mixing ratio of the polyethylene resin in the above, linear low density polyethylene is usually 75 to 98
%, Preferably 85 to 96% by weight, and the branched low density polyethylene is usually 25 to 2% by weight, preferably 15 to 96% by weight.
4% by weight. If the amount of the branched low-density polyethylene exceeds 25% by weight, the elongation of the film in a molten state is reduced, and it is difficult to process the film. On the other hand, if it is less than 2% by weight, it is difficult to obtain a film having a uniform thickness.

Next, examples of the filler include calcium carbonate, barium sulfate, calcium sulfate, barium carbonate, magnesium hydroxide, aluminum hydroxide, zinc oxide, magnesium oxide, titanium oxide, silica, and talc. Of these, calcium carbonate and barium sulfate are particularly preferred. The average particle size of such a filler is usually 20 μm or less, preferably 10 μm or less, particularly preferably 0.5 to 5 μm. The filler is desirably coated with a surface treating agent to make the surface of the filler hydrophobic to improve dispersibility in the resin. Examples of such a surface treating agent include stearic acid and lauric acid. And higher metal salts thereof and metal salts thereof.

[0010] The laminated porous film of the present invention comprises a resin composition containing the above polyolefin resin and a filler,
Resin compound (X) containing an amide compound as a third component
And an X layer and a Y layer using a resin composition (Y) to which at least one of an ester compound, a hydrocarbon polymer having a side chain, a silicone polymer, and a mineral oil is added as a third component. Things. The amide compound in the present invention is a mono- or polyamide compound comprising the following ammonia or amines and a carboxylic acid. The amines are saturated or unsaturated aliphatic amines and aromatic amines, and include diaminohexane, diaminopropane, diaminocyclohexane, diaminodecane, diaminooctane, diaminohydroxypropane, diaminobenzene, α, α 'Diaminoxylene, diaminobenzophenone, triaminobenzene, triaminotriazine and the like and derivatives thereof. The carboxylic acids include saturated or unsaturated carboxylic acids and aromatic carboxylic acids, such as acetic acid, octadecanoic acid, octadecenoic acid, octadecadienoic acid, cyclohexanecarboxylic acid, lactic acid, succinic acid, ketostearic acid, hydroxystearic acid, Examples include dihydroxystearic acid, sebacic acid, trimellitic acid, diaminobenzoic acid, epsilon caprolactam, amino acids and the like and derivatives thereof.

The above amide compound comprising an amine and a carboxylic acid includes a diamine having 3 or more carbon atoms and a diamine having 8 or more carbon atoms.
A compound comprising the above monocarboxylic acid or a compound comprising a monoamine having 7 or more carbon atoms and a dicarboxylic acid having 5 or more carbon atoms is particularly preferred in that the decrease in adhesiveness is small, and such an amide compound has an amino group A compound in which the terminal of a carbonyl group is left in the molecule may be used, but a compound blocked with an amide group is preferred. In particular,
Stearic acid amide, behenic acid amide, hexamethylenebisstearic acid amide, trimethylenebisoctylic acid amide, hexamethylenebishydroxystearic acid amide, trioctatrimellitic acid amido, distearyl urea butylene bisstearic acid amide, xylylene bisstearin Acid amide, distearyl adipamide,
Distearyl phthalic acid amide, distearyl octadecadioic acid amide, epsilon caprolactam and the like, and derivatives thereof, may be mentioned.

The ester compound may be any monoester or polyester having a structure composed of an alcohol and a carboxylic acid, but is preferably a compound blocked in the form of an ester group. Stearyl stearate, sorbitan tristearate Rate, hardened castor oil, epoxy soybean oil, refined castor oil, dehydrated castor oil,
Examples include epoxy soybean oil, extremely hardened oil, trioctyl trimellitate, ethylene glycol dioctanoate, and pentaerythritol tetraoctanoate. As the hydrocarbon polymer having a side chain, poly-α-olefins, preferably those having an oligomer region having a side chain having 4 or more carbon atoms, ethylene-propylene copolymer,
For example, Mitsui Petrochemical Industry Co., Ltd. product name Lucant and its maleic acid derivative, a polymer of isobutylene, such as Idemitsu Petrochemical Industry Co., Ltd. product name polybutene HV-100,
Alternatively, it may be an oligomer of butadiene or isoprene, a hydrogenated product thereof, or a derivative thereof. Any known silicone oil may be used, and examples thereof include polydimethylsiloxane and polymethylphenylsiloxane. Examples of the mineral oil include liquid paraffin and paraffin wax.

In the laminated porous film of the present invention, X
The thickness ratio between the layer and the Y layer is 1/10 to 10/1. The X layer alone is excellent in shielding properties but not enough in flexibility.
There is a problem that the shielding property tends to be insufficient with only the layer, and the layer ratio is not stable when the thickness ratio is out of the range, and it is difficult to perform uniform stretching. Then, by laminating the X layer and the Y layer in an appropriate range, well-balanced film properties can be exhibited. As the layer structure, X /
Y, X / Y / X, Y / X / Y, Y / X / Y ', X / Y /
X / Y / X, X / Y / X / Y '/ X, X / Y / X / Y'
And the like, but the configuration of X / Y and X / Y / X is preferable from the viewpoint of productivity. The thickness of such a laminated porous film is usually about 10 to 100 μm. 10
If it is less than μm, the film is easily broken, and if it exceeds 100 μm, the film becomes hard, and it is difficult to obtain a porous film having a cloth-like soft feeling and good texture, which is not preferable.

The laminated porous film of the present invention is produced from the resin compositions X and Y containing the above polyolefin resin, filler and specific third component. As the composition of the resin composition in this case, the polyolefin resin is usually 25 to
For 50 parts by weight, preferably 35 to 45 parts by weight, the filler is in the range of 75 to 50 parts by weight, preferably 65 to 55 parts by weight. If the amount of the filler is less than 50 parts by weight, adjacent voids formed by peeling off the interface between the polyolefin resin and the filler will not communicate with each other, and it will be difficult to obtain air permeability. On the other hand, if it exceeds 75 parts by weight, elongation during stretching of the film is lost, and stretching becomes difficult.

The addition of the third component to the resin composition is as follows:
Film thickness uniformity, stretchability, film texture,
This has a significant effect on film formability, film adhesion, and the like. If the added amount is too large, these bleed out from the film, and the adhesiveness is deteriorated. On the other hand, if the addition amount is too small, the film becomes hard and the texture deteriorates,
Thickness uniformity also worsens. Considering this point, the total amount of the third component is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the total amount of the polyolefin resin and the inorganic filler. In addition, in the resin composition, in addition to the above essential components, additives generally used for resin compositions,
For example, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizers, antifogging agents, antiblocking agents, antistatic agents, slip agents, coloring agents, etc., do not impair the properties of the porous film. You may mix | blend in the range of a degree.

The laminated porous film of the present invention is obtained by mixing the above resin composition using a Henschel mixer, a super mixer, a tumbler type mixer or the like, and then kneading the mixture with a single-screw or twin-screw extruder, a kneader or the like, and pelletizing. Become Then, the pellets are molded at a temperature equal to or higher than the melting point of the polyethylene resin, preferably equal to or higher than the melting point + 20 ° C. and lower than the decomposition temperature, by a known molding method such as an extruder equipped with a T-die or the like or an inflation molding machine equipped with a circular die. Melting and film formation using a machine. In some cases, the film can be directly formed by a molding machine without pelletizing. And X
The layer and the Y layer may be separately formed and then subjected to thermocompression bonding, or may be formed into a multilayer by extrusion lamination between the two layers.

The formed film is formed at room temperature to the softening point of the resin (JI) by a known method such as a roll method or a tenter method.
(Measured value according to SK6760), stretching is performed at least in a uniaxial direction to cause interfacial separation between the polyolefin resin and the inorganic filler to obtain a porous film. Stretching may be performed in one step or in multiple steps. Further, since the stretching ratio relates to tearing of the film during stretching, air permeability of the obtained film, softness of the film, and the like, it is not preferable that the ratio is too high or too low. From such a viewpoint, the stretching ratio in the present invention is usually 1.2 to 5 times, preferably 1.5 to 3 times. When biaxially stretching, first uniaxially stretching in the machine direction or in a direction perpendicular to it, then a method of stretching the second axis in a direction perpendicular to this direction, and machine direction, and perpendicular to it And simultaneously biaxially stretching in the direction of After the stretching, a heat setting treatment may be performed, if necessary, in order to stabilize the form of the obtained opening.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, the evaluation method performed in the Example is as follows. (1) Air permeability Measured according to JIS-P8117 (unit: sec / 5
0cc). (2) Stickiness Evaluated according to the following criteria by finger touch. ：: When the film surface is slid with a finger, it is not sticky and smooth. Δ: The film surface is slightly sticky when slid on the film surface with a finger. ×: When the film surface is slid with a finger, the film is sticky.

(3) Flexibility The flexibility was evaluated according to the following criteria. ：: No rustling sound even when the film was bent, and the feel was very good. ：: No rustling sound even when the film was bent, and the feel was good. Δ: The film does not make a rustling sound even when bent, but is slightly hard and uncomfortable. ×: A crunchy sound was produced even when the film was bent, and the film was hard and uncomfortable.

(4) Shielding property One side of a 25 mm wide double-sided adhesive tape (trade name: KOKUYO T-225) is adhered to one surface of the film to prepare a sample, and the remaining release paper is peeled off to obtain a total light transmittance of T1. It was measured. Also, one side of a double-sided adhesive tape having a width of 25 mm (trade name: KOKUYO T-225) was adhered to one surface of the film to form a sample. The sample was left in a constant temperature and humidity of 40 ° C. and 75% for one week, and then left at room temperature. The sample was peeled off and the remaining release paper was peeled off, and the total light transmittance of the sample was measured as T2. Then, the difference in total light transmittance (T (%) = T1−T2 (%)) was measured and evaluated according to the following criteria. ：: T is less than 20% ○: T is 20% or more and less than 30% Δ: T is 30% or more and less than 40% ×: T is 40% or more The measurement of total light transmittance was based on JIS-K6718. Haze meter (NDH-20 manufactured by Nippon Denshoku Co., Ltd.)
0) was used.

Examples 1 to 8, Comparative Examples 1 to 10 (X) Raw material: Linear low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: F in 38 parts by weight of polyethylene resin]
W20G, density: 0.921 g / cm ³ , MI: 1 g /
10 minutes] to 32 parts by weight (95% by weight in polyethylene resin) of branched low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: LF441, density: 0.919 g /
cm ³ , MI: 2 g / 10 min], 5 parts by weight, 62 parts by weight of calcium carbonate (average particle size 1.2 μm, fatty acid treatment), and the third component shown in Table 1 were mixed with a tumbler mixer, and then mixed in a tandem type. The mixture was uniformly kneaded at 220 ° C. using a kneading extruder and processed into pellets. (Y) Raw material: linear low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: FW20G, density: 0.9 in 37 parts by weight of polyethylene resin]
21 g / cm ³ , MI: 1 g / 10 min] to 32 parts by weight (95% by weight in a polyethylene resin) and a branched low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: LF4
41, density: 0.919 g / cm ³ , MI: 2 g / 10
Min] 5 parts by weight, calcium carbonate (average particle size 1.2 μm,
Fatty acid treatment) After 63 parts by weight of the third component shown in Table 1 was mixed with a tumbler mixer, the mixture was uniformly kneaded at 220 ° C using a tandem kneading extruder, and processed into pellets. Using an extruder equipped with a multilayer circular die, the above pellets were treated at 200 ° C. in two layers of X / Y (layer ratio 5
/ 5) After being melt-formed into a film, the film is monoaxially stretched in the machine direction at a stretch ratio of 2.0 times at a line speed of 20 m / min between a preheated roll stretched roll heated to 60 ° C. and a porous film having a thickness of 25 μm. I got Table 2 shows properties of the obtained porous film. Comparative Example 8 means a single-layered porous film having a thickness of 25 μm and comprising a composition using stearic acid amide as the third component.

Example 8, Comparative Example 11 (X) Raw material: Linear low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: F in 37 parts by weight of polyethylene resin]
W20G, density: 0.921 g / cm ³ , MI: 1 g /
10 minutes] to 32 parts by weight (95% by weight in polyethylene resin) of branched low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: LF441, density: 0.919 g /
cm ³ , MI: 2 g / 10 min], 63 parts by weight of calcium carbonate (average particle size 1.2 μm, fatty acid treatment),
After mixing the third component shown in Table 1 with a tumbler mixer, the mixture was uniformly kneaded at 220 ° C. using a tandem kneading extruder and processed into pellets. (Y) Raw material: Linear low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: FW20G, density: 0.
921 g / cm ³ , MI: 1 g / 10 min] to 32 parts by weight (95% by weight in a polyethylene resin) and a branched low-density polyethylene [manufactured by Nippon Polychem Co., Ltd., trade name: L
F441, density: 0.919 g / cm ³ , MI: 2 g /
10 minutes], 5 parts by weight of calcium carbonate (average particle size 1.2
(μm, fatty acid treatment) 63 parts by weight and 1 part by weight of the third component shown in Table 1 were mixed by a tumbler mixer, and then uniformly kneaded at 220 ° C. using a tandem kneading extruder to form pellets. . This pellet was subjected to X / Y / X at 200 ° C. using an extruder equipped with a multilayer T die.
After melt-forming with three layers of X (layer ratio 2/6/2),
The film was uniaxially stretched in the machine direction at a stretching speed of 2.1 times at a line speed of 20 m / min between a preheating roll and a stretching roll heated to obtain a porous film having a thickness of 25 μm. Table 2 shows the obtained physical properties.

[0023]

[Table 1]

The third component in Table 1 is as follows. Hardened castor oil: manufactured by Ito Oil Co., Ltd. Hardened castor oil Castor wax Dehydrated castor oil: manufactured by Ito Oil Co., Ltd. Product name: Dehydrated castor oil DCO Refined castor oil: manufactured by Ito Oil Co., Ltd. Refined castor oil LAV EBS: Nippon Chemical Co., Ltd. Product name Ethylenebisstearic acid amide Sribakx E DEA: Condensate produced by dehydration reaction of adipic acid and diethylene glycol at a molar ratio of 3: 2 Epoxy soybean oil: Product name Adekasizer O-13- manufactured by Asahi Denka Kogyo Co., Ltd. P DPEHO: Mitsubishi Chemical Co., Ltd. Product name Dipentaerythritol Exaoctanoate D-600 PHA: Mitsubishi Chemical Co., Ltd. Product name: Polytail HA PB: Nippon Yushi Co., Ltd. Product name: Nissan Polybutene 200SH Silicone Oil : Toshiba Silicone Product Name Dimethyl Silicone TS -451 Pentaerythritol Exaoctanoate D-600 TTO: manufactured by Mitsubishi Chemical Corporation Trade name: trioctyl trimellitate D-1174 EBS: manufactured by Nippon Kasei Co., Ltd., trade names: ethylenebisstearic acid amide, Srivac E Sakae OA: Nippon Kasei Co., Ltd., trade name oleic acid amide, Diamid O-200 SA: Nippon Kasei Co., Ltd., trade name Stearic acid amide, Amide AP-1 SS: Nippon Kasei Co., Ltd., product Name Stearyl stearic acid stearic acid amide, aamide, Nikka amide S HS: manufactured by Nippon Kasei Co., Ltd., trade name: 12-hydroxyhexamethylenebis 12-hydroxystearic amide, Diamid KH XBS: manufactured by Nippon Kasei Co., Ltd., meta name: meta Xylene bis stearamide, Slipax PXS HE MS: manufactured by Nippon Kasei Co., Ltd., trade name: hexamethylene bisstearic acid amide, Slipax ZHS HEBB: manufactured by Nippon Kasei Co., Ltd., trade name: hexamethylene bisbehenic acid amide, Slipax ZHS HMBHS: manufactured by Nippon Kasei Co., Product name Hexamethylene bis 12 hydroxystearic amide, Slipax ZHH

[0025]

[Table 2]

[0026]

Industrial Applicability The laminated porous film of the present invention has good adhesiveness and shielding properties while maintaining air permeability, uniform stretchability, and the like at or above the level of the conventional product, and has high flexibility. The texture is good. Therefore, sanitary materials such as disposable paper diapers, body fluid absorbing pads, bed sheets, etc., medical materials such as surgical gowns, base materials for hot compresses, clothing materials such as jumpers and rainwear, wallpaper, roof waterproof materials, etc. It can be very suitably used as a packaging material such as a material for use, a desiccant, a desiccant, an oxygen scavenger, a disposable body warmer, a packaging for keeping freshness, a food packaging, and a separator for a battery.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/10 C08K 5/10 5/20 5/20 C08L 23/00 C08L 23/00 83/04 83 / 04 // B29K 23:00 B29K 23:00 105: 16 105: 16 B29L 7:00 B29L 7:00 F term (reference) 4F074 AA16 AA17 AA26 AA64 AA90 AA98 AC26 AD11 AD13 AG01 CA02 CA05 CA06 DA10 DA17 DA23 DA53 4F100 AH02B AH02C AH03A AH03C AK03 AK03A AK03B AK03C AK06 AK08B AK08C AK52B AK52C AK63 BA02 BA03 BA06 BA10A BA10B BA10C BA15 CA23A CA23B CA23C CA30A CA30B CA30C DJ06A DJ06B DJ06C EH17 EJ37 GB07 GB15 GB23 GB66 GB72 JD02 JK06 JK13 JK17 4J002 AE053 BB03W BB03X BB04W BB04X BB06W BB06X BB12W BB12X BB14W BB14X BB15W BB15X BB153 BB17W BB17X BB173 BL013 BL023 BP02W BP02X CD163 CP033 DE076 DE106 DE136 DE146 DE236 DG046 DG056 DJ016 DJ046 EH047 EP017 EP027 ET017 EU017 FB236 FD016 GB00 GF00 GL00

Claims (4)

[Claims] 1. A porous film obtained by melt-forming a composition containing a polyolefin resin, a filler and a third component to form a film, and then subjecting the film to a stretching treatment. An X layer containing a compound, and a Y layer containing at least one or more of an ester compound, a hydrocarbon polymer having a side chain, a silicone polymer, and a mineral oil as the third component, wherein the thickness ratio of the X layer and the Y layer is 1/10
A laminated porous film, wherein the ratio is from 10/1 to 10/1. 2. A multi-layer structure of X / Y, X / Y / X, Y / X
/ Y. The laminated porous film of claim 1, wherein 3. The porous film according to claim 1, wherein the amide compound comprises a diamine having 3 or more carbon atoms and a monocarboxylic acid having 8 or more carbon atoms. 4. An amide compound wherein the third component has 7 carbon atoms.
3. The porous film according to claim 1, comprising said monoamine and a dicarboxylic acid having 5 or more carbon atoms.