JP3169389B2 - Filler-containing stretched film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretchable film containing a gas-permeable filler having excellent tensile strength, appearance, texture and tear strength.

[0002]

2. Description of the Related Art A breathable film having voids which are continuous (penetrated) by stretching a film made of a composition of an olefin resin and an inorganic filler in a uniaxial or biaxial direction is already known. It is known that, when these films are manufactured to be thin and have a low draw ratio, local necking causes uneven thickness due to unevenness, which significantly impairs commercial value. Therefore, for example, a composition to which a known third additive is added has been proposed in Japanese Patent Application Laid-Open No. Sho 62-18435, and a film using this composition is used for sanitary materials such as disposable disposable diapers. It has begun to be used for.

[0003]

However, although these resin compositions are effective in compensating for the above-mentioned disadvantages, they have the disadvantage that the stretchability during molding and the tear strength of the film when the thickness is reduced are inferior. ing. An object of the present invention is to provide a filler-containing stretched film that has solved these disadvantages.

[0004]

Means for Solving the Problems The present inventors have achieved the above object by adding a specific linear ethylene copolymer, a specific inorganic filler and a fatty acid ester, thereby achieving a good balance of various physical properties. The inventors have found that a film can be obtained, and have completed the present invention.

That is, the present invention provides the following (a):
(B) and (c) each component, and (a) component and (b)
Component (c) is 0.1 to 15 parts by weight with respect to 100 parts by weight of component (a) being 20 to 80% by weight and component (b) being 80 to 20% by weight based on the total amount of components. ASTM D1922-61T
The filler-containing stretched film has a tear strength MD (machine direction: machine direction) of 10 g or more.

(A) Density 0.910 to 0.945 g / cm
³ and a melt flow rate of 0.01 to 20 g / 10 min, containing 1 to 20% by weight of an α-olefin or diolefin comonomer having 6 or more carbon atoms, and a boiling normal hexane extraction amount of 20% by weight or less. Linear ethylene copolymer.

(B) A granular inorganic filler having an average particle size of 10 μm or less and a bulk density of 0.1 to 0.7 g / cm ³ .

(C) A saturated or unsaturated fatty acid ester having 9 to 40 carbon atoms.

The preferred linear ethylene copolymer of the component (a) used in the present invention has a density of 0.915 to 0.935 g / cm.
^3. A linear low-density polyethylene (LL-L) having a melt flow rate of 0.1 to 20 g / 10 min, a comonomer content of 2 to 15% by weight, and a boiling normal hexane extraction amount of 15% by weight or less.
DPE), and more preferably a density of 0.915 to 0.915.
0.930 g / cm ³ , melt flow rate 0.1 to 10
It is L-LDPE having a g / 10 min, a comonomer content of 2 to 10% by weight, and a boiling normal hexane extraction amount of 10% by weight or less.

Still more preferably, the density is 0.91.
8 to 0.930 g / cm ³ , melt flow rate 0.3 to
L-LD with 10 g / 10 min, comonomer content of 3 to 10% by weight, and boiling normal hexane extraction amount of 8.5% by weight or less
PE is most preferred, with a density of 0.920 to
0.930 g / cm ³ , melt flow rate 0.5-3 g
L-LDPE having a comonomer content of 3 to 10% by weight and a boiling normal hexane extraction amount of 5% by weight or less.

Here, the density was measured according to JIS K 6760-1971, and the melt flow rate was measured according to ASTM.
According to D1238 (190 ° C.), the comonomer content was measured by infrared spectroscopy. The method of measuring the amount of boiling normal hexane extracted was according to the method described in Examples below.

L-LDPE having a density below the above range is:
If the stretched film has a large decrease in air permeability and blocking resistance, and exceeds the above range, the tensile strength, tear strength and hand of the stretched film are deteriorated.

If the melt flow rate is lower than the above range, the moldability is poor, and if it is higher, the moldability and the strength of the stretched film are reduced.

Further, those having a comonomer content outside the above-mentioned range are not preferred in view of the strength and rigidity of the stretched film.

[0015] When the boiling normal hexane extraction amount exceeds the above range, the stretched film has a large decrease in air permeability and blocking resistance.

As the comonomer, an α-olefin or diolefin having 6 or more carbon atoms, preferably 6 to 24 carbon atoms is used. When an α-olefin or diolefin having 5 or less carbon atoms is used in place of these comonomers, there is a drawback that stretchability during film production and tensile strength and tear strength of the stretched film are poor. Further, those having a flow ratio (measurement method described in Examples) of 6 to 10 are preferable in terms of tensile strength and tear strength of the stretched film.

Such a copolymer is prepared by adding hexene-1,4-methylpentene-1 as a comonomer to ethylene.
Octene-1, decene-1, dodecene-1, hexadecene-1, dococene-1,1,5-hexadiene, 1,7
-Octadienes, 1,9-decadienes and the like, which are obtained by copolymerizing one or more of them. When two or more comonomers are copolymerized with ethylene, propylene, butene-1, 1, 1, or
An α-olefin or diolefin having 5 or less carbon atoms, such as 3-butadiene, can be used in an amount that does not significantly impair the effects of the present invention.

The method for producing the copolymer is as follows:
Under the conditions of 500 kg / cm ² and a temperature of 50 to 300 ° C., ethylene and the above α-olefin are copolymerized using a Ziegler type, vanadium type or Kaminsky type catalyst. For example, a method described in JP-B-56-18132 is known.

In the present invention, in order to particularly improve the tear strength MD and the film appearance of the obtained stretched film, it is preferable to use a granular or powdery linear ethylene copolymer. Is 0.001 to 0.7 mm, preferably 0.01 to 0.6 mm, and the particle size distribution is 70% by weight or more for 1.68 mm or less, 50% by weight or more for 0.84 mm or less, and 1 for 0.21 mm or less. Granular or powdery linear ethylene copolymer having a weight percentage of at least 0.5% by weight, more preferably at least 70% by weight of at most 1.68mm, at least 50% by weight of at most 0.84mm and at least 10% by weight of at most 0.21mm It is preferred to use coalescence.

Here, the measuring method of the average particle size and the particle size distribution is as follows.

<Measurement Method of Average Particle Size and Particle Size Distribution> (i) Definition The linear ethylene copolymer is subjected to particle size classification using standard sieves of various sizes, and the weight distribution is defined as the particle size distribution.

Further, the weight average sieve size calculated using the weight percentages of the sieve sizes classified by the particle size is defined as the average particle size.

(Ii) Apparatus and instruments 1) Shaker 2) Standard sieve JIS Z 8801 compliant (3.5, 10.5, 20, 32, 48, 70, 14)
5, 200, 350 mesh sieve and receiver) 3) Precision balance

(Iii) Test method 1) The standard sieve and the receiver to be used are cleaned with a bristle brush, and then cleaned with an air blow. 2) Measure the weight of the sieve and the receiver (w1). Assemble each sieve in order from the one with the smaller opening at the bottom. 3) Weigh 100 g ± 5 g of the sample with a precision balance (w
2) Load the sample from the top. 4) Fix the sieve on a shaker and shake for 15 minutes. 5) Take out the sieve and determine the weight of each sieve containing the sample and the receiver (w).

(Iv) Calculation method 1) Particle size distribution The weight percentage of the fraction of each sieve is determined by the following equation. W = [(w−w1) / w2] × 100 where, W: weight percent (wt%) of the separated material of each sieve w: weight (g) of each sieve and sample including the sample after shaking w1: Weight of each sieve and receiver (g) w2: Total weight of sample (g) 2) Average particle size The average particle size is determined from the following formula using the weight percentage of the fractions of each sieve. D = Σ (Wn × dn) / 100 where, D: average particle size of sample (mm) Wn: weight percent of separated material of each sieve (wt%) dn: size of mesh of each sieve (mm)

When a linear α-olefin or a linear diolefin is used as a comonomer constituting the linear ethylene copolymer, a non-linear α-olefin or a non-linear The stretched film obtained has a remarkably high tear strength MD as compared with the case of using a chain diolefin, which is preferable.

The component (b) used in the present invention has an average particle size of 1
0 μm or less, preferably 0.1 to 5 μm, more preferably 0.5 to 2 μm granular inorganic filler having a bulk density of 0.1 to 0.7 g / cm ³ , preferably 0.2 to 0.6 g
/ Cm ³ , more preferably 0.3 to 0.5 g / cm ³ . Here, in order to obtain the average particle diameter, the specific surface area is measured by an air permeation method, and is calculated by the following equation. dm: average particle diameter (μm) dm = 60,000 / (ρ · Sw) ρ: true specific gravity of powder (g / cm ³ ) Sw: specific surface area of powder (cm ² / g)

As an apparatus for measuring the specific surface area, for example, a Shimadzu SS-100 powder specific surface area measuring apparatus can be used, and the specific surface area is determined by applying the Kozeny-Carman equation.

The method for measuring the bulk density conformed to JIS K 5101.

When the average particle size is larger than the above range, the appearance of the stretched film is impaired, and when a thin stretched film having a thickness of 100 μm or less is produced, perforations are produced.
Uneven stretching occurs, and stable stretchability is impaired. If the bulk density is below the above range, the air permeability of the stretched film is reduced, and if it is higher, the tensile strength is impaired. "granular"
Is a sphere, a square shape or a shape close to this,
It is not needle-shaped, rod-shaped or plate-shaped. If the shape of the inorganic filler is needle-like, rod-like, or plate-like, satisfactory microvoids cannot be imparted to the stretched film.

Examples of such inorganic fillers include calcium carbonate, calcium oxide, zeolite, amorphous aluminosilicate, clay, synthetic silica, titanium oxide, alumina, barium sulfate, aluminum sulfate, magnesium hydroxide and the like. Calcium, zeolite,
Amorphous aluminosilicate, barium sulfate, synthetic silica, magnesium hydroxide and the like are preferable, and calcium carbonate and barium sulfate are particularly preferable. These can be used alone or 2
A mixture of more than one species can be used. The water content of the inorganic filler (b) is 3,000 ppm or less,
Those having 0 ppm or less are preferred. If the water content exceeds this, the foaming phenomenon is apt to occur, and stable film forming becomes difficult, poor hue and poor appearance of the film and the like, and the filler is liable to secondary aggregation, thereby further poor appearance. In addition, poor stretching tends to occur.

The component (c) used in the present invention has 9 to 9 carbon atoms.
40 unsaturated or unsaturated fatty acid esters, and specific examples of the unsaturated fatty acid ester include (poly)
Ethylene glycol oleate, (poly) propylene glycol oleate, glyceryl oleate, sorbitan oleate, (poly) ethylene glycol sorbitan oleate, butyl oleate, pinacol oleate, m-cresol oleate, pentaeristol oleate, Glyceryl linolenate, glyceryl ricinolate, methyl ricinolate, ethyl ricinolate, butyl ricinolate, methyl acetyl ricinolate, ethyl acetyl ricinolate, butyl acetyl ricinolate, (poly) ethylene glycol ricinolate, glyceryl acetyl ricinolate, glyceryl Elsiete and the like can be mentioned. Among them, glyceryl hydroxy fatty acid esters are preferred, and glyceryl ricinoleate is particularly preferred.

Further, specific examples of the saturated ester include:
(Poly) ethylene glycol laurate, (poly) propylene glycol laurate, glyceryl laurate,
Sorbitan laurate, (poly) ethylene glycol sorbitan laurate, glyceryl myristate, glyceryl palmitate, butyl stearate, ethylene glycol stearate, propylene glycol stearate, pinacol stearate, m-cresol stearate, (poly) ethylene glycol Stearate, (poly) propylene glycol stearate, glyceryl stearate, pentaerythritol stearate, sorbitan stearate, (poly) ethylene glycol sorbitan stearate, methylhydroxystearate,
Ethyl hydroxystearate,

Butylhydroxystearate, methylacetylhydroxystearate, ethylacetylhydroxystearate, butylacetylhydroxystearate, ethylene glycol hydroxystearate, propylene glycol hydroxystearate, pinacol hydroxystearate, m-cresol hydroxystearate , (Poly) ethylene glycol hydroxystearate, (poly) propylene glycol hydroxystearate, pentaerythritol hydroxystearate, sorbitan hydroxystearate, ethylene glycol sorbitan hydroxystearate, glyceryl hydroxystearate, glycerylacetyl hydroxystearate and the like. be able to.

Among them, ethylene glycol hydroxystearate, propylene glycol hydroxystearate, pinacol hydroxystearate, m-cresol hydroxystearate, (poly) ethylene glycol hydroxystearate, (poly) propylene glycol hydroxystearate, pentaerythritol hydroxystearate Glyceryl hydroxy saturated fatty acid esters such as glyceryl hydroxystearate, ethylene glycol sorbitan hydroxystearate, glyceryl hydroxystearate and glyceryl acetyl hydroxystearate are preferred. Most preferred is glyceryl hydroxystearate, especially glyceryl-12-hydroxystearate.

When a saturated ester is used as the fatty acid ester, it is more preferable than in the case where an unsaturated ester is used, in that almost no smoke is generated at the time of molding and the obtained stretched film is excellent in odorlessness. .

The mixing ratio of each of these components (a), (b) and (c) is as follows:
Component (a) is 20 to 80% by weight and component (b) is 80 to 20% by weight, preferably 30 to 70% by weight of component (a), based on the total amount of component (a) and component (b). b) 70-30% by weight of component, more preferably 35-35% of component (a)
60% by weight and 65 to 40% by weight of the component (b). For a total of 100 parts by weight of the components (a) and (b),
Component (c) is 0.1 to 15 parts by weight, preferably 0.5 to 15 parts by weight.
7 parts by weight, more preferably 1 to 5 parts by weight.

If the component (b) is below the above range, the air permeability and texture of the stretched film are reduced, and if it exceeds the above range, the stretchability during film production or the tensile strength and tear strength of the stretched film are reduced. This leads to disadvantages such as deterioration of the commercial value.

When the component (c) is below the above range, when a stretched film is produced with a small thickness and a low stretching ratio, the thickness is not uniform due to local necking, resulting in unevenness and significantly impairing the commercial value. Conversely, if the ratio exceeds the above range, the moldability decreases, and the breathability and blocking resistance of the stretched film are undesirably reduced.

The tensile strength, air permeability, appearance,
In order to make the balance between the feel, the stretchability and the tear strength particularly good, preferably, the above-mentioned granular or powdery component is used as the component (a), and the component (a) and the component (b) are mixed. The mixture was mixed well with a blender such as a Henschel mixer, and the mixture was further added with the component (c). The mixture was melt-kneaded with a twin-screw kneading extruder, a Banbury mixer or a kneader, and then pelletized. It is desirable to use a composition.

In the present invention, antioxidants, stabilizers, dispersants, lubricants, antiblocking agents, pigments, antifogging agents, antistatic agents, ultraviolet absorbers, light stabilizers, and nuclei commonly used in the composition. An additive such as an agent may be blended.

Further, linear ethylene such as a copolymer of ethylene and an α-olefin or diolefin having 5 or less carbon atoms, a high-pressure low-density polyethylene, a high-density polyethylene, a polypropylene, a polybutene, and an ethylene-vinyl acetate copolymer. The present invention can be applied to a composition in which a resin or rubber component other than the copolymer (a) is blended within a range that does not significantly impair the effects of the present invention.

The composition used in the present invention is formed into a film such as a film, sheet or tape by T-die molding, inflation molding or the like, and then stretched uniaxially or biaxially at a normal stretching temperature. And a stretched film can be manufactured. This stretching method may be a conventionally known method, specifically, flat roll stretching, oven stretching or tube stretching in uniaxial stretching, and flat tenter stretching or tube stretching in biaxial stretching. Methods such as inflation stretching and mandrel stretching. The stretching ratio is 1.2 to 6.0 times, preferably 1.2 to 4.0 times.

The thickness of the obtained stretched film is 5 to 30.
0 μm, preferably 10 to 50 μm is practical.

The stretched film thus obtained is
A tear strength MD according to ASTM D1922-61T of 1
0 g or more, preferably 15 g or more, particularly preferably 20 g or more. A stretched film having a tear strength MD below this range cannot be satisfactorily applied to the intended use of the present invention.

[0046]

The filler-containing stretched film of the present invention comprises:
The film has good stretchability during film production, particularly excellent tear strength, and balances tensile strength, air permeability, appearance, and texture. Therefore, it is useful for sanitary materials such as disposable diapers, sanitary products, medical clothing, and building materials such as anti-condensation agents.

When a saturated fatty acid ester is used as the component (c), almost no smoke is generated during molding, and the obtained stretched film has excellent odorlessness.

[0048]

EXAMPLES Examples 1 to 3 and Comparative Examples 1 to 6 Ethylene copolymers corresponding to the component (a) shown in Table 1
First, using the inorganic filler of the component (b) and the fatty acid ester of the component (c), the components (a) and (b) are mixed with a Henschel mixer, and the component (c) is added and mixed. The mixture was extruded at a temperature of 200 ° C. using a shaft kneading extruder (screw diameter: 65 mm) to obtain pellets of each composition. In Comparative Example 6, as the component (a), polyethylene produced by a high-pressure radical polymerization method was used.

[0049]

[Table 1]

[Table 7]

Each of these compositions was processed into a film by the following method. An extruder (screw diameter 50 mm, L /
D24) and T-die (300mm width, lip width 1.2mm)
The film was extruded into a film at 230 ° C., and was uniaxially stretched at a stretching temperature of 85 ° C. and a stretching ratio of 3 by a short section hot stretching roll to produce a 30 μm thick breathable film.

The quality of the film thus obtained was evaluated for the following items. The measuring method is as follows.
The evaluation results are shown in Table 2.

The melt flow rate (MFR) is
The flow ratio (FR) was determined according to ASTM D1238 (190 ° C.) and JIS K 7210-1975 (190 ° C.) using a melt indexer based on the following formula. FR = (MFR under load of 10 kg) / (MFR under load of 2.16 kg)

The average particle size of the filler is determined by the Coulter counter method (dispersion method is 28 KC ultrasonic for 5 minutes,
0.01% sodium hexametaphosphate).

Boiling normal hexane extraction amount Film thickness 3 at 200 ° C. by air-cooled inflation molding
After 5 g of the film extruded to 0 μm is put into a cylindrical filter paper, extraction is carried out at the boiling point for 8 hours with a Soxhlet extraction device into which 200 ml of normal hexane has been injected. After drying the cylindrical filter paper with a vacuum dryer for 60 minutes, the weight loss is measured.

The composition was extruded using an extruder (screw diameter 50 mm, L / D24) and T-die (300 mm width, lip width 1.2 mm).
The film is extruded at 30 ° C., and is uniaxially stretched at a stretching temperature of 85 ° C. with a short-section hot stretching roll, and the maximum stretching ratio at which the film is cut is measured.

Tensile strength Measured according to ASTM D882-67.

Measured in accordance with JIS Z 0208-1973.

[0058] Tear strength MDASTM D1922-
Measured according to 61T.

Odor The formed film was cut and 30 g was placed in an Erlenmeyer flask, which was evaluated by a sensory test. A: Almost no odor
B: Smell slightly C: Smell

Smoke emission The presence or absence of smoke emission during film formation was evaluated.

Film appearance test The appearance abnormality (streaks, unevenness, bumps, etc.) on the surface of the formed film was visually observed. A: good B: slightly bad C: extremely bad

[0062]

[Table 2]

Examples 4 to 8 and Comparative Examples 7 to 12 Except that the ethylene copolymer having various particle size distributions shown in Table 3 was used instead of the ethylene copolymer corresponding to the component (a), Each composition was obtained in the same manner as in Examples 1 to 3, processed into a film and evaluated in the same manner as in Examples 1 to 3. The evaluation results are shown in Table 3.

[0064]

[Table 3]

[Table 8]

Examples 9 to 11 and Comparative Examples 13 and 14 In the same manner as in Examples 1 to 3, except that the ethylene copolymer shown in Table 4 was used instead of the ethylene copolymer corresponding to the component (a). In the same manner as in Examples 1 to 3, each composition was obtained, processed into a film, and evaluated. The results of the evaluation, together with the above example, were compared with the fourth example so that the comonomer types could be compared.
It is shown in the table.

[0066]

[Table 4]

[Table 9]

Examples 12 and 13 and Comparative Examples 15 to 17 Using the ethylene copolymer (a), the inorganic filler (b) and the fatty acid ester (c) shown in Table 5, Each of the compositions was obtained in the same manner as in Examples 1 to 3, processed into a film in the same manner as in Examples 1 to 3, and evaluated. Table 5 shows the evaluation results.

[0068]

[Table 5]

[0069]

[Table 6]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B29K 23:00 B29L 7:00 (72) Inventor Hideo Uchiyama 1 Tohocho, Yokkaichi, Mie Prefecture Mitsubishi Yuka Yokkaichi Sogo (56) References JP-A-63-43932 (JP, A) JP-A-2-36938 (JP, A) JP-A-59-70521 (JP, A) (58) Fields studied (Int. . ^7, DB name) C08J 5/18 CES B29C 55/02 C08K 3/00 C08K 5/10 C08L 23/08 B29K 23:00 B29L 7:00

Claims (1)

(57) [Claims] 1. It comprises the following components (a), (b) and (c), wherein the component (a) is 20 to 80% by weight based on the total amount of the components (a) and (b) and ( b) component is 80
Component (c) is added in an amount of 0.1 to 20 parts by weight of 100 parts by weight.
Consisting of a resin composition having a blending ratio of 1 to 15 parts by weight,
Tear strength MD (ma according to ASTM D1922-61T)
A stretched film containing filler, characterized in that the chine direction is 10 g or more. (A) When the density is 0.915 to 0.935 g / cm ³ and the melt flow rate is 0.1 to 20 g / 10 min, the comonomer of α-olefin or diolefin having 6 or more carbon atoms is 2-1.
Boiling normal hexane extraction amount containing 5% by weight is 15
% Or less by weight of a linear ethylene copolymer. (B) The average particle size is 10 μm or less, and the bulk density is 0.1 to
0.7 g / cm ³ granular inorganic filler. (C) A saturated or unsaturated fatty acid ester having 9 to 40 carbon atoms.