JPH0826191B2 - Composition for polypropylene film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composition for polypropylene film. Specifically, the surface smoothness and transparency immediately after film formation are good,
The present invention relates to a polypropylene film composition having excellent transparency, which hardly changes even after aging.

[Prior art]

Crystalline polypropylene (hereinafter abbreviated as PP) is widely used as a packaging material because of its excellent heat resistance, chemical resistance, electrical properties, optical properties, mechanical properties such as rigidity and tensile strength, and processability. .

In particular, a film formed as a packaging material is required to maintain a good balance of transparency, surface smoothness, and antiblocking property.

Conventionally, saturated or unsaturated higher fatty acid amides, the same aluminum bisamides or fatty acid monoglycerides are generally added as lubricants in order to obtain the surface lubricity of PP films. Further, in order to obtain anti-blocking property, inorganic fine powder, for example, silica, zeolite, talc, calcium carbonate, anti-blocking agent to the extent that the fine powder of fine powder such as diatomaceous earth does not impair the transparency (hereinafter, (Abbreviated as AB agent)) is used in combination with the above lubricant.

[Problems to be solved by the invention]

However, as described above, the amount of the AB agent used can be added only in a range that does not impair the transparency of the film, and when a sufficient amount of the lubricant is included to obtain good film surface lubricity immediately after film formation. As a result, the lubricant excessively bleeds with time or in an environment of high temperature, which leads to deterioration of transparency.

Surface lubricity can be supplemented by reducing the use of lubricants and increasing the amount of the above-mentioned AB agent added to prevent the adhesion between films, but AB agent deteriorates the transparency of the film when the addition amount is increased. Let

Therefore, an object of the present invention is to provide a film composition which has good surface slipperiness, antiblocking property and transparency in a film immediately after film formation and has no problem in transparency even with time.

[Means for solving problems]

The present inventors have made diligent studies to solve the above problems,
When a specific siloxane compound is used in combination with a lubricant and an AB agent for PP, a film having excellent film surface smoothness and transparency immediately after film formation and having little change in transparency even after a long period of time can be obtained. This has led to the completion of the present invention.

That is, the present invention, with respect to 100 parts by weight of polypropylene, 0.01 to 0.9 parts by weight of antiblocking agent, 0.0
A composition for a polypropylene film, characterized by containing 5 to 0.5 part by weight and 0.01 to 0.5 part by weight of a modified polymethylsiloxane shown below.

In the proton nuclear magnetic resonance spectrum of the modified polymethylsiloxane measured at 24 ° C. in a deuterated chloroform solution having a concentration of 75 mg / ml, the resonance absorption intensity based on the methyl group directly bonded to silicon is based on a, and based on the methyl group bonded to carbon. When the resonance absorption intensity is b and the resonance absorption intensity based on a methylene group and a methine group bonded to oxygen is c, the following relational expression is calculated from these a, b and c. The value of A obtained in 1 is 1/8 or more.

The PP used in the present invention is a known stereoregular catalyst, for example, a catalyst composed of a transition metal catalyst and an organometallic compound, a catalyst obtained by supporting a transition metal compound on a carrier such as magnesium chloride, and the like. It is a homopolymer of propylene obtained by a polymerization method such as a solvent polymerization method, a bulk polymerization method or a gas phase polymerization method, or a copolymer of propylene with another α-olefin. As α-olefin, ethylene, butene-1,
Pentene-1,4-methylpentene-1, hexene-
1, heptene-1, octene-1, vinylcyclohexane, styrene, α-methylstyrene and the like can be exemplified, and these are used alone or in combination of two or more of which ethylene,
Butene-1 is often used. The content of other α-olefin in the copolymer is 40% by weight or less, preferably 10% by weight or less.

As for PP, its melt flow index (AS
TM D-1238, 230 ° C, 2.16Kg. Hereinafter, abbreviated as MFI) is preferably 3 to 30 g / 10 min.

As the lubricant used in the present invention, stearic acid amide,
C6-C22 saturated and unsaturated fatty acid amides such as behenic acid amide, oleic acid amide, and erucyl acid amide,
N, N'-C13-45 N, N'-methylenebisoleic acid amide, N, N'-methylenebiserucic acid amide, etc.
Examples thereof include alkylenebisamides and fatty acid monoglycerides such as stearic acid monoglyceride, and one or more of these are added in an amount of 0.05 to 0.5 parts by weight per 100 parts by weight of PP. If the amount added is less than 0.05 parts by weight, the surface lubricity will be insufficient, and if the amount added exceeds 0.5 parts by weight, the transparency after aging will tend to be insufficient.

The AB agent used in the present invention is a fine powder of an inorganic substance such as silica, zeolite, talc, calcium carbonate, diatomaceous earth, and the average particle diameter of which is 6 μm or less, preferably 3 μm or less.

The amount of the AB agent added to PP is preferably 0.01 to 0.9 parts by weight. If it is less than 0.01 parts by weight, the formed films will be in close contact with each other, and the opening property will be insufficient particularly in the case of an inflation film. Further, if it exceeds 0.9 parts by weight, the transparency is deteriorated and the commercial value is impaired.

What is important in the present invention is to use a specific modified polymethylsiloxane, which is characterized by having the following specific proton nuclear magnetic resonance spectrum.

That is, the modified polymethylsiloxane used in the present invention was a deuterated chloroform solution having a concentration of 75 mg / ml, the proton nuclear magnetic resonance spectrum was measured at 24 ° C., and the resonance based on the methyl group directly bonded to silicon was obtained in the obtained spectrum. When the absorption intensity is a, the resonance absorption intensity based on a methyl group bonded to carbon is b, and the resonance absorption intensity based on a methylene group and a methine group bonded to oxygen is c, these a,
The following relational expression from b and c The value of A obtained in 1 is 1/8 or more.

Incidentally, when the proton nuclear magnetic resonance spectrum is measured using tetramethylsilane as a standard, the modified polymethylsiloxane used in the present invention shows that the signal based on the methyl group directly bonded to silicon is usually δ value of −0.1 to +0.2 ppm. A signal based on a methyl group bonded to carbon usually appears in the range of 0.9 to 1.2 ppm as a δ value, and a signal based on a methylene group and a methine group bonded to oxygen is usually δ.
The value appears in the range of 3.2 to 3.8 ppm. Therefore, in the present invention, the above a, b and c are values measured using the resonance absorption intensities appearing in this portion.

The modified polymethylsiloxane used in the present invention is presumed to have the following structure.

(In the formula, l, m, and n are natural numbers, and R is-.
CH ₂ CH ₂ — and / or —CH (CH ₃ ) CH ₂ —. ) In the film formed by using the modified polymethylsiloxane whose A obtained by the above relational expression is less than 1/8, the bleeding of the modified polymethylsiloxane becomes excessive when the film is left for a long time or under a high temperature environment. Stickiness and blocking of the film surface are likely to occur.

In the present invention, there is no particular upper limit for A determined by the above relational expression, but it is preferably 4 or less.

As the molecular weight of the modified polymethylsiloxane, preferably, the viscosity at 25 ° C. is 100 to 4000 cSt,
When a modified polymethylsiloxane having a viscosity of less than 100 cSt is used, the surface lubricity of the film is insufficient, and when a viscosity of more than 4000 cSt is used, the transparency and blocking properties of the film are poor and the workability is poor. Not preferable.

The modified polymethylsiloxane is preferably added in an amount of 0.01 to 0.5 parts by weight per 100 parts by weight of PP. If it is less than 0.01 parts by weight, the surface smoothness of the film immediately after film formation is not sufficient, and the amount added exceeds 0.5 parts by weight. And the film surface becomes sticky, which rather deteriorates the surface smoothness.

In the present invention, it goes without saying that various additives which are generally used as additives to polypropylene, such as stabilizers, antioxidants and hydrochloric acid scavengers, can be added.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

 The definition of the characteristic value used in the present invention is shown below.

(1) Haze Based on ASTM D-1003.

(2) Film surface lubricity Using a friction measuring machine manufactured by Toyo Seiki Co., Ltd., measurement is performed under the following conditions, and the sliding angle (θ) of the block load is read and displayed in tan θ.

Inclination speed: 2.7 ° / sec Block area: 6.3cm × 6.3cm Block weight: 200g (3) Blocking property Two films cut into a predetermined size are stacked, a load of 20g / cm ² is applied, and a constant temperature of 50 ° C is applied. After leaving it in the chamber for 24 hours, it was taken out from the temperature-controlled room, and the contact area ratio of the film was determined (by the naked eye).

(4) Opening property The opening condition of the inflation film is judged by the feeling of the finger.

(5) Isotactic index (II) Residue after extraction with boiling n-heptane for 10 hours. In addition,
The appropriate physical property values of the film obtained from the composition of the present invention are in the ranges shown below.

(1) Film immediately after film formation 1. Haze inflation film: 3.5% or less Casting film: 3.0% or less (however, 2.0% or less for propylene homopolymer) 2. Film surface smoothness inflation film: 0.4 or less Casting film : 0.6 or less (2) Blocking casting film: 50% or less (3) Opening inflation film: Good (4) Haze after aging ・ 23 ° C x 60 days: 1.0% or less difference from immediately after film formation ・ 40 ℃ × 60 days: difference from immediately after film formation is 1.5% or less Example 1 Propylene homopolymer (II = 96%, MFI = 8.0g / 10mi
n) powder 100 parts by weight, fine powder silica (particle size 5 μm or less, average particle size 1.8 μm) 0.25 part by weight, erucylamide
0.07 parts by weight, modified polymethylsiloxane "TSF4460" manufactured by Toshiba Silicone Co., Ltd. (A = 1.8, viscosity at 25 ° C. = 250 cS
t) 0.30 part by weight, 2,6-ditertbutyl-p-methylphenol 0.10 part by weight, calcium stearate 0.10 part by weight and tetrakis [methylene- (3,5-ditertbutyl-4
0.10 parts by weight of -hydroxyphenyl) propionate] methane was uniformly mixed with a Henschel mixer. After that, the cylinder, head, and die were each adjusted to 250 ° C, and 65mm
Pellets were obtained by melt extrusion with a φ extruder. The MFI of the obtained pellet was 9.0 g / 10 min.

Then, the pellets were adjusted to a temperature of 250 ° C, 270 ° C, and 250 ° C with a cylinder, a head, and a die, respectively, and 40 mmφT
It was extruded with an extruder with a die (L / D = 22) to obtain a castig film having a thickness of 30 μm.

The obtained film was evaluated for haze immediately after film formation, surface smoothness, blocking property, and haze of the film stored at 23 ° C. for 60 days and at 40 ° C. for 60 days. All physical properties were within the appropriate range.

 The results are shown in Table-1.

Comparative Example 1 Pelletization and film formation were carried out in the same manner as in Example 1 except that dimethyl silicone oil “TSF451” (viscosity at 25 ° C. = 5000 cSt) manufactured by Toshiba Silicone Co., Ltd. was used in place of the modified polymethylsiloxane.

The obtained film had poor surface smoothness, blocking property and haze after aging.

 Table 1 shows the measured physical properties.

Example 2 As polypropylene, II is 72% and MFI is 6.0 g / 10 min.
Then, using a propylene-ethylene copolymer having an ethylene content of 4.2% by weight, fine powder silica was increased to 0.40 parts by weight and erucylamide was increased to 0.15 parts by weight, and modified polymethylsiloxane manufactured by Toshiba Silicone Co., Ltd. as modified polymethylsiloxane. Siloxane "TSF4446" (A = 0.31, viscosity at 25 ℃ = 1700
CSt) was pelletized and filmed in the same manner as in Example 1 except that 0.20 part by weight was used.

The MFI when pelletized was 7.0 g / 10 min. In addition, when various physical properties of the film were measured, the results shown in Table 1 were obtained.

Comparative Example 2 A 35/65 mixture (A = 0.11, 25 ° C.) of the modified polymethylsiloxane used in Example 2 and the dimethyl silicone oil used in Comparative Example 1 (viscosity at 25 ° C. = 5000 cSt).
A casting film was obtained in the same manner as in Example 2 except that the viscosity of 3800 cSt) was used.

The obtained film had a poor haze after aging.

 Table 1 shows the measured physical properties.

Example 3 As polypropylene, II is 72% and MFI is 6.0 g / 10 min.
Then, using a propylene-ethylene copolymer having an ethylene content of 4.2% by weight, fine powder silica was increased to 0.50 parts by weight, and erucylamide was increased to 0.30 parts by weight, and used as modified polymethylsiloxane in Examples 1 and 2. Pelletization was carried out in the same manner as in Example 1 except that 0.20 part by weight of a mixture (A = 1.1, viscosity at 25 ° C = 980 cSt) of the same was used.

 The obtained pelletized MFI was 7.0 g / 10 min.

The pellets thus obtained were formed into a film with a blow ratio of 1 using an extruder with 40 mmφ inflation (L / D = 22) in which the cylinder, head, and die were adjusted to 220 ° C, 220 ° C, and 210 ° C, respectively, and a thickness of 30 μm was folded. An inflation film having a diameter of 185 mm was obtained.

Various physical properties of the obtained film were measured and shown in Table-1.
Was obtained.

Example 4 0.70 parts by weight of finely divided silica and 0.45 of erucylamide.
An inflation film was obtained in the same manner as in Example 3 except that 0.45 parts by weight of the modified polymethylsiloxane used in Example 1 was used.

Various physical properties of the obtained film were measured and shown in Table-1.
Was obtained.

Comparative Example 3 An inflation film was obtained in the same manner as in Example 4 except that the addition amount of fine powder silica was 1.0 part by weight.

 The haze of the obtained film was poor.

The results of measuring various physical properties of the obtained film are shown in Table-1.
Shown in

Comparative Example 4 An inflation film was obtained in the same manner as in Example 4 except that the addition amount of fine powder silica was 0.005 parts by weight.

The obtained film had poor surface smoothness and openability.

The results of measuring various physical properties of the obtained film are shown in Table-1.
Shown in

Example 5 As polypropylene, II is 40%, MFI is 9.0g / 10min
With ethylene content of 4.9% by weight and butene-1 content of 4.5% by weight, propylene-ethylene-butene-1 terpolymer is used, fine powder silica is reduced to 0.05 parts by weight, and erucylamide is 0.20 parts by weight. Pelletization and film formation were carried out in the same manner as in Example 2 except that the number of parts was increased.

Various physical properties of the obtained film were measured and shown in Table-1.
Was obtained.

Comparative Example 5 A casting film was obtained in the same manner as in Example 5, except that the amount of erucylamide added was increased to 0.60 parts by weight.

The obtained film had a poor haze after aging.

 Table 1 shows the measured physical properties.

Comparative Example 6 A casting film was obtained in the same manner as in Example 5 except that the addition amount of erucylamide was reduced to 0.02 part by weight.

 The surface smoothness of the obtained film was poor.

 Table 1 shows the measured physical properties.

Example 6 In Example 1, an inflation film was obtained in the same manner as in Example 3 except that fine powder silica was increased to 0.30 parts by weight, erucylamide was increased to 0.25 parts by weight, and modified polymethylsiloxane was decreased to 0.03 parts by weight.

Various physical properties of the obtained film were measured and the results shown in Table 1 were obtained.

Comparative Example 7 An inflation film was obtained in the same manner as in Example 6 except that the amount of modified polymethylsiloxane was increased to 0.70 parts by weight.

The obtained film had poor surface smoothness, openability, and haze after aging.

 Table 1 shows the measured physical properties.

Comparative Example 8 An inflation film was obtained in the same manner as in Example 6 except that 0.005 parts by weight of the modified polymethylsiloxane used in Example 2 was used.

The obtained film had poor surface smoothness and haze after aging.

 Table 1 shows the measured physical properties.

Example 7 Pelletization and film formation were carried out in the same manner as in Example 1 except that 0.07 part by weight of oleic acid amide was used instead of erucyl amide.

The various physical properties of the obtained film were all within the appropriate range.

 Table 1 shows the measured physical properties.

Example 8 Pelletization and film formation were carried out in the same manner as in Example 2 except that 0.15 parts by weight of stearic acid amide was used instead of erucyl amide.

The various physical properties of the obtained film were all within the appropriate range.

 Table 1 shows the measured physical properties.

Example 9 Pelletization and film formation were carried out in the same manner as in Example 3 except that 0.50 part by weight of finely powdered zeolite (particle size: 15 μm or less, average particle size: 2 μm) was used as the AB agent.

The various physical properties of the obtained film were all within the appropriate range.

 Table 1 shows the measured physical properties.

Example 10 Pelletization and film formation were carried out in the same manner as in Example 6 except that fine powder talc (particle size: 3 μm or less, average particle size: 2 μm) was used as the AB agent.

The various physical properties of the obtained film were all within the appropriate range.

 Table 1 shows the measured physical properties.

: Note in Table-1 * 1 In the composition, the type of polypropylene means homopolymer, binary means propylene-ethylene copolymer, and ternary means propylene-ethylene-butene-1 copolymer. The AB agent is finely divided silica (particle size 5 μm or less, average particle size 1.8 μm) except for Examples 9 and 10, and the lubricant is erucyl amide except Examples 7 and 8. Furthermore, other than those shown here, 2,6-ditertbutyl-p-
Methylphenol 0.10 parts by weight, calcium stearate
0.10 parts by weight and tetrakis [methylene- (3,5-diter
t-butyl-4-hydroxyphenyl) propionate]
It contains 0.10 parts by weight of methane.

* 2 The types of film are shown below.

CPP: Casting film IPP: Inflation film * 3 Oleic acid amide (Example 7) or stearic acid amide (Example 8) was used instead of erucyl amide as a lubricant.

* 4 Fine powder zeolite (particle size 15 μm or less, average particle size 2 μm, Example 9) or fine powder talc (particle size 3 μm or less, average particle size 2 μm, Example 10) is used as the AB agent instead of fine powder silica. I was there.

〔The invention's effect〕

The composition for a polypropylene film obtained by the present invention has excellent transparency and surface slipperiness immediately after film formation, and can provide an inflation film and a casting film with almost no change in transparency even after aging. It is extremely excellent.

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Claims (1)

[Claims] 1. An anti-blocking agent 0.01 to 0.9 parts by weight, a lubricant 0.05 to 0.5 parts by weight, and a modified polymethylsiloxane 0.01 shown below per 100 parts by weight of polypropylene.
A composition for a polypropylene film, characterized in that the composition comprises 0.5 to 0.5 parts by weight. In the proton nuclear magnetic resonance spectrum of the modified polymethylsiloxane measured at 24 ° C. in a deuterated chloroform solution having a concentration of 75 mg / ml, the resonance absorption intensity based on the methyl group directly bonded to silicon is based on a, and based on the methyl group bonded to carbon. When the resonance absorption intensity is b and the resonance absorption intensity based on the methylene group and methine group bonded to oxygen is c, these a,
The following relational expression from b and c The value of A obtained in 1 is 1/8 or more.