JP3235055B2 - Multilayer film of propylene-based random copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer film of a propylene random copolymer.

[0002]

2. Description of the Related Art A crystalline propylene polymer film has been widely used as a packaging film because of its excellent rigidity, transparency and moisture-proof property. However, the propylene homopolymer film has a great difficulty in low-temperature heat sealing when performing bag making and bag closing after filling the contents, so that a resin excellent in heat sealing is conventionally used as a sealant. As a layer, it is widely used as a laminated film laminated on one or both sides thereof.

[0003] As means for improving the low-temperature heat sealability,
Conventionally, copolymerization of ethylene and other α-olefins has been widely performed, but in order to obtain sufficient low-temperature heat sealability, it is necessary to copolymerize a large amount of ethylene and other α-olefins. Accordingly, a large amount of tacky component is formed as a by-product, causing a problem such as a significant decrease in anti-blocking properties, which is not practical. Also,
As a solution to this problem, a method of removing the sticky component by dissolving it in an inert solvent has also been attempted. However, at present, the desired low-temperature heat sealability has not been obtained although the sticky component can be removed. .

[0004] In recent years, the heat seal layer has tended to be made thinner for the purpose of increasing the resin for the layer and increasing the rigidity of the entire laminated film, so that a very high heat seal strength is required. In such a case, it is necessary to consider not only the resin properties of the heat seal layer but also the resin properties of the base material layer. Therefore, attempts have been made to copolymerize a small amount of ethylene, 1-butene, etc. in the base material layer.However, in the conventional technology, the copolymer has a large decrease in crystallinity of the resin and has insufficient rigidity. Not.

[0005] Further, in addition to the good low-temperature heat sealability, which is directly related to the productivity of the bag making process and the bag closing process after filling the contents, the film has a film rewinding process. It is required to exhibit slip property and anti-blocking property and to have good appearance and transparency in order to perform the process smoothly. In recent film processing, high-speed film formation is performed by a large-sized molding machine in order to increase productivity. In this case, it is also required that the film quality does not deteriorate.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer film exhibiting a balance between extremely high rigidity and low-temperature heat sealability without impairing the inherent desirable properties of a polypropylene film as much as possible. It is.

[0007]

(Propylene-based random copolymer (A))

Propylene random copolymer satisfying the following (A-1) to (A-6) (A) (A-1) Ethylene unit content in copolymer [χa (wt%)]
(A-2) The melt index of the copolymer [MIa (g / 10mi
n)] is 4 to 12 g / 10 min. (A-3) Boiling diethyl ether extraction amount [Ea (wt%)] and χa
Satisfies the relationship of formula (1) Ea ≤ 0.25 χa + 1.1 (1) (A-4) Melting point [Tma (° C)] measured with a differential scanning calorimeter and χa satisfy the relationship of formula (2) Tma ≦ 165 −5 χa (2) (A-5) The isotactic triad fraction [mm fraction a (mol%)] of the PPP chain part measured by ¹³ C-NMR is 98 mol.
l% or more (A-6) the melt index of the copolymer [MIa (g / 10mi
n)] and the frequency ω ₀ = 10 obtained by the frequency dispersion measurement
The relaxation time τ (sec) at ⁰ rad / sec is
Τ ≦ 0.65-0.025 MIa that satisfies the relationship (8) [Propylene random copolymer (B)] Propylene random copolymer (B) satisfying the following (B-1) to (B-6) (B) (B -1) Content of ethylene unit in copolymer [χb (wt%)]
Is 0.2 to 15 wt% (B-2). The melt index of the copolymer [MIb (g / 10mi
n)] is 0.1 to 15 g / 10min. (B-3) Boiling diethyl ether extraction amount [Eb (wt%)] and χb
Eb ≤ 0.2 関係 b +1.0 (0.2 ≤ χb <5) (3) Eb ≤ 2.0 (5 ≤ χb ≤ 15) (4) (B-4) Tmb ≦ 140 (0.2 ≦ χb <4) (5) Tmb ≦ 160 −5 χb (4) where the melting point [Tmb (° C.)] measured by a scanning calorimeter and χb satisfy the relationship of equation (5) or (6). ≦ χb ≦ 15) (6) (B-5) The isotactic triad fraction [mm fraction b (mol%)] of the PPP chain part measured by ¹³ C-NMR is 90 mol.
l% or more (B-6) Percentage of PEP chain portion measured by ¹³ C-NMR [R
(mol%)] and χb satisfy the relationship of formula (7). R ≧ 0.5 χb + 1.0 (7) ( 2 ) The propylene-based random copolymer (A) has the following (A-
The multilayer film of the propylene-based random copolymer according to the above ( 1 ), which satisfies (7). (A-7) Content of ethylene unit in copolymer [χa (wt%)]
There Ru 1 to 4 wt% der (3) the propylene random copolymer (B) the surface layer and the propylene random copolymer (A) thickness ratio of the base layer made of consisting of (surface layer / substrate layer) is 0 The multilayer film of the propylene-based random copolymer according to (1) or (2) , which is in the range of 0.005 to 0.5.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below. The multilayer film of the propylene-based random copolymer of the present invention has a surface layer made of a random copolymer of propylene and ethylene (B) on at least one surface of a base material layer made of the propylene-based random copolymer (A). It is a feature.

This propylene random copolymer (A)
Satisfies the following (A-1) to (A-6) . (A-1) Content of ethylene unit in copolymer [χa (wt%)]
Is 0.2 to 4% by weight, preferably 0.5 to 3.5% by weight. χa
Is less than 0.2 wt%, the low-temperature melting property of the base material layer becomes insufficient, and particularly when the surface layer is thin, the low-temperature heat sealability decreases. Further, since the crystallinity becomes too high, transparency and film impact become insufficient particularly when the film forming speed is increased. On the other hand, when χa exceeds 4 wt%, the rigidity is reduced, and the anti-blocking property is also reduced due to the effect.

(A-2) Melt index of copolymer (M
Ia (g / 10min)) is 4-12 g / 10min, preferably 5-10
g / 10min. When the MIa is less than 4 g / 10 min, transparency and film impact may be reduced. on the other hand,
If the MIa exceeds 12 g / 10 min, molding failure tends to occur.

(A-3) The amount of boiling diethyl ether extracted (Ea
(wt%)) and χa satisfy the relationship of equation (1). Ea ≦ 0.25χa + 1.1 (1) When Ea is larger than this range, when the copolymer (A) is an outer layer, the antiblocking property is reduced.

Preferably, Ea ≦ 0.2χa + 1.1 (1) ′.

(A-4) The melting point (Tma (° C.)) measured by a differential scanning calorimeter and χa satisfy the relationship of the formula (2). Tma ≦ 165−5χa (2) When Tma is higher than this range, the low-temperature melting property of the base material layer becomes insufficient, and particularly when the surface layer is thinned, the low-temperature heat-sealing property deteriorates.

Preferably, Tma ≦ 162−5χa (2) ′.

[0015] ^{(A-5) 13 C-} NMR isotactic triad fraction of the PPP chain portion as measured by (mm fraction a (mo
l%)) is 98 mol% or more, preferably 98.5 mol% or more. When the mm fraction a is less than 98 mol%, the amount of sticky components increases and the antiblocking property decreases.
Further, the crystallinity is reduced, and the rigidity is also reduced accordingly. Further, the decrease in the melting point with respect to the copolymerization amount is small, and the melting point cannot be sufficiently lowered.

This propylene random copolymer (A)
Are those that satisfy the following to (A-6). (A-6) Melt index of copolymer [MIa (g / 10mi
n)] and the frequency ω ₀ = 10 obtained by the frequency dispersion measurement
The relaxation time τ (sec) at ⁰ rad / sec satisfies the relationship of Expression (8).

Τ ≦ 0.65−0.025 MIa (8) If τ is larger than this range, transparency and film impact tend to decrease particularly when the film forming speed is increased. Preferably, τ ≦ 0.63−0.025 MIa (8) ′ .

On the other hand, a propylene random copolymer (B)
Satisfies the following (B-1) to (B-6). (B-1) Content of Ethylene Unit in Copolymer (wtb (wt%))
Is from 0.2 to 15% by weight, preferably from 4 to 15% by weight, more preferably from 5 to 10% by weight. When χb is less than 0.2 wt%, the heat sealing temperature cannot be lowered sufficiently and the crystallinity increases, so that the impact resistance tends to decrease particularly when the film forming speed is increased. If χb exceeds 15 wt%, the rigidity decreases, the tackiness component increases, and the antiblocking property decreases.

(B-2) Melt index of copolymer (M
Ib (g / 10min)) is 0.1 to 15 g / 10min, preferably 4 to 1
It is 2g / 10min. More preferably, 5 to 10 g / 10 min
It is. When the MIb is less than 0.1 g / 10min, transparency,
Film impact is reduced. If the MIb exceeds 15 g / 10 min, molding failure tends to occur.

(B-3) Extraction amount of boiling diethyl ether (Eb
(wt%)) and χb satisfy the relationship of equation (3) or (4). Eb ≦ 0.2χb + 1.0 (0.2 ≦ χb <5) (3) Eb ≦ 2.0 (5 ≦ χb ≦ 15) (4) If Eb exceeds this range, the anti-blocking property decreases. . Further, the heat sealing temperature cannot be sufficiently lowered.

Preferably, Eb ≦ 0.2χb + 0.5 (0.2 ≦ χb <5) (3) ′ Eb ≦ 1.5 (5 ≦ χb ≦ 15) (4) ′.

(B-4) The melting point (Tmb (° C.)) measured by a differential scanning calorimeter and Δb satisfy the relationship of the formula (5) or (6). Tmb ≦ 140 (0.2 ≦ χb <4) ・ ・ ・ (5) Tmb ≦ 160−5χb (4 ≦ χb ≦ 15) ・ ・ ・ (6) If Tmb is higher than this range, the heat sealing temperature will be sufficiently lowered Can not do.

Preferably, Tmb ≦ 140 (0.2 ≦ χb <3) (5) ′ Tmb ≦ 155−5χb (3 ≦ χb <15) (6) ′.

[0024] ^{(B-5) 13 C-} NMR isotactic triad fraction of the PPP chain portion as measured by (mm fraction b (mo
l%)) is at least 90 mol%, preferably at least 94 mol%. P represents a propylene unit. mm fraction b is
If it is less than 90 mol%, the amount of sticky components increases, and the anti-blocking property decreases. Further, the crystallinity is reduced and the rigidity is also reduced. Further, the decrease in the melting point relative to the copolymerization amount is small, and the heat sealing temperature cannot be sufficiently lowered.

[0025] Also (B-6) ¹³ ratio of PEP chain portion as measured by C-NMR [R (mol% )] and χb satisfy the relationship of formula (7)
It is. E represents an ethylene unit. R ≧ 0.5χb + 1.0 (7) If R is lower than this, the melting point drop relative to the copolymerization amount becomes small, and the heat sealing temperature cannot be sufficiently lowered. In addition, the tackiness component increases and the anti-blocking property decreases.

Preferably, the relationship of R ≧ 0.5χb + 2.0 (7) ′ is satisfied . In addition, the multilayer film of the propylene-based random copolymer of the present invention has a thickness ratio (surface layer / base) of the surface layer composed of the propylene-based random copolymer (B) and the base layer composed of the propylene-based random copolymer (A). (Material layer) in the range of 0.005 to 0.5 is preferable. More preferably, it is in the range of 0.01 to 0.2.

If the ratio exceeds 0.5, the rigidity of the whole film tends to be insufficient. On the other hand, if it is less than 0.005, molding becomes difficult, and it becomes difficult to exhibit sufficient low-temperature heat sealability.

The propylene random copolymer of the present invention
(A) and (B), in combination with the specific catalyst component as indicated below, but those who came in first manufacturing by selecting a specific ethylene supply amount and the hydrogen supply amount,
The production method is not limited to this, and any method may be used as long as the above-mentioned propylene-based random copolymers (A) and (B) can be obtained.

The catalysts usable in the production include a solid catalyst component (a) containing magnesium, titanium and halogen as essential components, an organoaluminum compound (b), and a catalyst formed from a specific organosilicon compound (c). As typical examples, the following catalyst components can be used.

(A) Solid catalyst component A preferred carrier for the solid catalyst component is obtained from metal magnesium, an alcohol, a halogen and / or a halogen-containing compound. In this case, the metallic magnesium
Granular, ribbon, and powdered magnesium can be used. Further, it is preferable that the metallic magnesium has no surface formed with a coating such as magnesium oxide.

As the alcohol, it is preferable to use a lower alcohol having 1 to 6 carbon atoms. In particular, when ethanol is used, the above-mentioned carrier which significantly improves the expression of the catalytic performance can be obtained.

As the halogen, chlorine, bromine or iodine is preferable, and iodine can be particularly preferably used. Also,
MgCl ₂ and MgI ₂ can be suitably used as the halogen-containing compound. The amount of alcohol is preferably from 2 to 100 mol, particularly preferably from 5 to 50 mol, per mol of metallic magnesium.

The amount of the halogen or the halogen-containing compound used is such that the amount of the halogen atom or the halogen atom in the halogen-containing compound is 0.1 to 1 gram atom of metallic magnesium.
It is at least 0001 gram atoms, preferably at least 0.0005 gram atoms, and more preferably at least 0.001 gram atoms. The halogen and the halogen-containing compound may be used each alone or two or more of them may be used in combination.

The method of reacting the magnesium metal with the alcohol and the halogen and / or the halogen-containing compound is, for example, the reaction of the metal magnesium with the alcohol and the halogen and / or the halogen-containing compound by generating hydrogen gas under reflux (about 79 ° C.). Until it is no longer recognized (usually 20-30
H) reacting to obtain a carrier. This is preferably performed in an inert gas (eg, nitrogen gas, argon gas) atmosphere.

When the obtained carrier is used for the synthesis of the following solid catalyst component, it may be used after drying, or after filtration and washing with an inert solvent such as heptane.

The carrier is nearly granular and has a sharp particle size distribution. Further, even if each particle is taken, the variation in granularity is very small. For the production of the solid catalyst component, at least a titanium compound is brought into contact with the above-mentioned carrier.

The titanium compound is represented by the general formula (9) TiX¹ _n(OR¹)_4-n ... (9) (where X¹Is preferably a halogen atom, especially a chlorine atom
K, R¹Is a hydrocarbon group having 1 to 10 carbon atoms, particularly a linear or
Is a branched alkyl group;¹When there are multiple
They may be the same or different from each other. n is 0
4 is an integer. )
Can be. Specifically, Ti (OiC
_ThreeH₇)_Four, Ti (OC_FourH₉)_Four, TiCl (O-
C_TwoH_Five)_Three, TiCl (OiC_ThreeH₇)_Three, Ti
Cl (OC_FourH₉)_Three, TiCl_Two(OC_FourH₉)
_Two, TiCl_Two(OiC_ThreeH₇)_Two, TiCl_Fouretc
And particularly, TiCl_FourIs preferred.

The solid catalyst component can be obtained by further contacting the above carrier with an electron donating compound. As the electron donating compound, an aromatic dicarboxylic acid diester is preferable, and di-n-butyl phthalate is particularly preferable. Further, when the titanium compound and the electron donating compound are brought into contact with the above-mentioned carrier, a halogen-containing silicon compound such as silicon tetrachloride may be brought into contact.

The above solid catalyst component can be prepared by a known method. For example, there is a method in which the above carrier, the electron-donating compound and the halogen-containing silicon compound are charged into an inert hydrocarbon such as pentane, hexane, peptane or octene as a solvent, and the titanium compound is charged with stirring. Usually, the electron-donating compound is added in an amount of 0.01 to 10 mol, preferably 0.05 to 5 mol, per mol of the carrier in terms of magnesium atom. The compound is added at 1 to 50 mol, preferably 2 to 20 mol, at 0 to 200 ° C for 5 minutes to 10 hours, preferably at 30 to 150 ° C.
The contact reaction may be performed under conditions of 30 minutes to 5 hours.

After the completion of the reaction, it is preferable to wash the generated solid catalyst component with an inert hydrocarbon (for example, n-hexane or n-heptane).

[0041] (b) As the organoaluminum compound The organoaluminum compound of the general formula _{^{(10) AlR 2 n X 2}} 3-n ··· (10) ( wherein, R ² is an alkyl group having 1 to 10 carbon atoms , A cycloalkyl group or an aryl group, X ² is a halogen atom, preferably a chlorine atom or a bromine atom.
It is an integer of 3. ) Is widely used. Specific examples include trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum monochloride, diisobutylaluminum monochloride, diethylaluminum monoethoxide, and ethylaluminum sesquichloride. These may be used alone or in combination of two or more.

Of these, triethylaluminum and triisobutylaluminum are preferred.

(C) Organosilicon Compound As the organosilicon compound, dicyclopentyldimethoxysilane can be preferably used. The above solid catalyst component is used for polymerization after pretreatment. For example, the above solid catalyst component, the organoaluminum compound and the organosilicon compound are charged into an inert hydrocarbon such as pentane, hexane, peptane or octene as a solvent, and propylene is supplied and reacted while stirring. Usually, the organoaluminum compound is present in an amount of 0.01 to 10 mol, preferably 0.0 to 10 mol, per 1 mol of titanium atoms in the solid catalyst component.
The organosilicon compound is added in an amount of 0.01 to 20 mol, preferably 0.1 to 5 mol, per 1 mol of titanium atoms in the solid catalyst component. Propylene is supplied under a partial pressure of propylene higher than atmospheric pressure,
The pretreatment may be performed at 100 ° C. for 0.1 to 24 hours.
After completion of the reaction, it is preferable to wash the pretreated material with an inert hydrocarbon (for example, n-hexane or n-heptane).

The polymerization conditions are not particularly limited, and the same conditions as in a known method can be used. For example, it can be produced under a partial pressure of propylene higher than the atmospheric pressure and at a temperature of -80 to 150C. Preferably, 20 to 1
At a temperature of 50 ° C., the partial pressure of propylene is between atmospheric pressure and 40 k
g / cm ² G. Usually, the organoaluminum compound is added in an amount of 0.1 to 400 mol, preferably 1 to 200 mol, per 1 mol of titanium atoms in the solid catalyst component, and the organosilicon compound is added in 1 mol of titanium atoms in the solid catalyst component. 0.1-100 mol, preferably 1-5 mol, per mol
0 moles may be added.

The ethylene content and the molecular weight are affected by both ethylene and hydrogen in the polymerization apparatus. The ethylene content is mainly controlled by the ethylene supply amount, and the copolymer molecular weight is mainly controlled by the hydrogen supply amount. It must be adjusted in quantity and selected to give the desired ethylene content and molecular weight.

By manufacturing as described above, PPP
It is possible to increase the stereoregularity of the chain portion and randomly copolymerize ethylene therewith, thereby obtaining a propylene-based random copolymer having high crystallinity and a low melting point. Since the copolymerizability is good, the melting point can be effectively lowered with a small amount of copolymerization. Further, the composition distribution becomes narrow, and a composition having a small sticky component (evaluated as a boiling diethyl ether-soluble component), which is a cause of blocking of the film, can be obtained.

The propylene random copolymer of the present invention
(A) and (B) can be blended with a commonly used additive, specifically, an antioxidant, a neutralizing agent, a slip agent, an antiblocking agent, an antistatic agent, or the like, if necessary.
The multilayer film of the propylene-based random copolymer of the present invention may be formed by separately forming a substrate layer and a surface layer, and then laminated by a known dry lamination method, or may be simultaneously formed by a known co-extrusion film forming method. It may be a film.

The propylene random copolymer of the present invention
(A) and (B) are respectively a base layer and a surface layer (functionally a heat-sealing layer), for example, in a T-die casting method, a high-speed film forming method with a take-up speed of 50 m / min or more. Under the conditions, a film having a thickness of 10 to 500 μm can be suitably formed. As a film forming method that can be employed, a T-die casting film forming method capable of high-speed film forming by a large film forming machine is preferable, but is not limited thereto.
Any method can be used as long as a film can be produced by a melt extrusion molding method.

[0049]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. First, a method for evaluating resin characteristics, a method for forming a film, and a method for evaluating film quality will be described. (A) Evaluation method of resin properties 1) Content of ethylene unit in copolymer (χa, χb (w
t%)) Ethylene content of 300 μm thick sheet was prepared under the following conditions, and 718/73 using FT / IR5300 manufactured by JASCO.
It was calculated from the absorbance at 3 cm ^-1 by the following equation.・ Sheet forming conditions Press temperature: 220 ° C Pressing / cold pressure: 50 kg / cm ² G Residual heat: 5 min; Pressurization: 5 min; Cold pressure: 3 min ・ IR measurement conditions Total number of times: 20 ; resolution: 4 cm ^-1 ethylene content (χa, χb (wt%) ) χ 1 = 0.599 × (A 733 / d · l) -0.161 × (A 718
_{/ D · l) χ 2 =} 0.599 × (A 718 / d · l) -0.161 × (A 733
/ D · l) χ = 0.809 × (χ ₁ + χ ₂ ) where A ₇₁₈ : absorbance at 718 cm ⁻¹ , A ₇₃₃ : absorbance at 733 cm ⁻¹ , d: 0.9, l: sample thickness.

2) Melt index (MIa, MIb
(g / 10min)) According to JIS K7210, it was measured at a temperature of 230 ° C. and a load of 2160 g. 3) Amount of boiling diethyl ether extracted (Ea, Eb (wt%)) 3 g of pellets pulverized to a mesh path of 1 mmφ into cylindrical filter paper, 160 ml of extraction solvent diethyl ether in a flat-bottomed flask, reflux frequency Extract once for about 5 min and extract with a Soxhlet extractor for 10 hours. After the extraction, the diethyl ether was recovered by an evaporator, further dried in a vacuum dryer until the weight became constant, and the amount of boiling diethyl ether extracted was determined from the weight.

4) Melting point of copolymer (Tma, Tmb (° C.)) measured by differential scanning calorimeter Differential scanning calorimeter (DSC7 manufactured by PerkinElmer)
10 mg of sample in advance in a nitrogen atmosphere at 230 ° C
After melting for 3 min, cool down to 40 ℃ at 10 ℃ / min. After maintaining at this temperature for 3 min, the temperature was raised at 10 ° C./min, and the peak top of the maximum peak of the melting endothermic curve obtained was taken as the melting point.

5) Isotactic triad fraction (mm fraction a, mm fraction b (mol%)) of the propylene copolymer and the copolymer measured by ¹³ C-NMR and the PPP chain portion of the film The isotactic triad fraction of the PPP chain is the isotactic fraction of triad units in the PPP chain of the copolymer molecular chain, and can be determined from a ¹³ C-NMR spectrum.

In the case of a propylene homopolymer, the following formula
You can calculate it with (I).

[0054]

(Equation 1)

However, Imm, Imr and Irr are ¹³ C
-The peak intensity | strength of each area | region when a methyl carbon area | region is divided into 3 area | regions of mm, mr, and rr in an NMR spectrum is shown. The mm region is a chemical shift of 21.4 to 2
2.2 ppm, mr region is 20.6 to 2 in chemical shift.
1.4 ppm, rr region is 19.8 to 2 in chemical shift.
0.6 ppm.

In the case of a propylene-based random copolymer,
The position of the methyl carbon absorption of the propylene unit adjacent to the ethylene unit is affected by the ethylene unit. Specifically, the absorption peak of the methyl carbon of the propylene unit in the EPE chain appears in the rr region, and the absorption peak of the methyl carbon of the propylene unit in the center of the PPE chain appears in the mr region.

The absorption peak intensity of methyl carbon of propylene unit in this EPE chain was Tδδ (33.3 ppm)
The peak intensity of can be substituted. Further, the absorption peak intensity of methyl carbon of propylene unit in this PPE chain is S
A peak intensity of αγ (38.0 ppm) can be substituted.
Therefore, the following equation (II) is used to determine the isotactic triad fraction of the PPP chain of the propylene-based random copolymer.

[0058]

(Equation 2)

The ¹³ C-NMR spectrum was measured using a JNM-EX400 type NMR apparatus manufactured by JEOL Ltd.
The measurement conditions are as follows. Sample concentration: 220 mg / NMR solvent 3 ml NMR solvent: 1,2,4-trichlorobenzene / deuterated benzene (90 / 10vol%) Measurement temperature: 130 ° C Pulse width: 45 ° Pulse repetition time: 4 seconds Integration count: 4000 times

6) Relaxation time τ Frequency ω ₀ = 10 when frequency dispersion measurement was performed at a temperature of 175 ° C. using a cone plate (diameter: 25.0 mm, cone angle: 0.10 radian) in a rotary rheometer manufactured by Rheometrics. The relaxation time τ (sec) at ⁰ rad / sec, which was calculated as follows.

[0061] When the defined σ ^* / γ ^* by the complex modulus G ^* (iω) a complex stress sigma ^* and the complex distortion γ ^*, G ^* (i
ω) is G ^* (iω) = σ ^* / γ ^* = G ′ (ω) + iG ″ (ω), and τ (ω) is τ (ω) = G ′ (ω) / ωG ″ (ω ) Where ω: frequency (rad / sec), G ′: storage elastic modulus,
G ": loss elastic modulus.

(A) Method for Forming Multilayer Film Pellets of propylene-based random copolymers (A) and (B) are cast by a three-layer T-die co-extrusion cast molding machine to a total film thickness of 30 μm (total discharge: The film was formed under the following conditions so as to have a weight of 80 kg / hr and a take-up speed of 70 m / min). The molding machine is provided with a 50 mmφ / 65 mmφ / 40 mmφ extruder corresponding to the surface layer / substrate layer / surface layer, the die exit resin temperature is 260 ° C., the chill roll temperature is 23 ° C., and the corona treatment is performed. The density is 38W / m ²
/ Min. (a) Layer composition: (B) / (A) / (B) (layer ratio = 1/5/1) Screw rotation speed (surface layer / substrate layer / surface layer): 30
/ 130/40 (rpm) (b) Layer composition: (B) / (A) / (B) (layer ratio = 1/10/1) Screw rotation speed (surface layer / substrate layer / surface layer): 20
/ 150/25 (rpm)

(C) Evaluation method of film quality All film qualities were measured at 23 ± 2 ° C. and 50 ± 10% humidity.
After conditioning for more than 16 hours, the measurement was performed under the same temperature and humidity conditions. 7) Heat sealing characteristics Measured according to JIS K-1707. The fusion conditions are described below. The temperature of the heat seal bar is calibrated by a surface thermometer. After sealing, the film was allowed to stand at room temperature for 24 hours, and then at room temperature, the peeling rate was 200 mm / min, and the peeling strength was measured by a T-type peeling method. The heat sealing temperature was determined by calculating the temperature at which the peel strength reached 300 g / 15 mm from a seal strength-peel strength curve.

Sealing time: 2 sec Sealing area: 15 × 10 mm Sealing pressure: 5.3 kg / cm ² Sealing temperature: Several points so that heat sealing temperature can be interpolated Sealing surface: Surface layer (propylene-based random copolymer)
(B))

8) Tensile modulus Measured by a tensile test according to JIS K7127. The measurement conditions were as follows. Crosshead speed: 500 mm / min Measurement direction: Machine direction (MD direction) Load cell: 10 kg

9) Anti-blocking property The two superposed films were evaluated by the peel strength after they were brought into close contact under the following conditions. Adhesion conditions: temperature: 60 ° C, time: 3 hr, load: 36 g / cm ² The conditions of the peeling test are as follows.

Test speed: 20 mm / min Load cell: 2 kg The measurement surface was a corona treated surface / corona treated surface, and a non-treated surface /
Two conditions of the non-treated surface were set.

10) Slip property After a film-covered threat is left on a glass-covered glass plate, the glass plate is tilted to evaluate the slant angle θ when the threat starts to slide. Using a friction angle measuring device manufactured by Toyo Seiki Seisaku-sho, the measurement was performed under the following conditions. Inclination speed: 2.7 ° / sec Thread weight: 1 kg Thread cross section: 65 cm Pressure between ^two surfaces: 15 g / cm ² Measurement surface is corona treated surface / corona treated surface, and non-treated surface /
Two conditions of the non-treated surface were set. 11) Transparency (haze and gloss) Measured according to JIS K7105. 12) Film impact In a film impact tester manufactured by Toyo Seiki Seisaku-sho, evaluation was made by the impact fracture strength using a 1/2 inch impact head.

[Example 1] [1] Propylene random copolymer (A) (1) Preparation of magnesium compound A reaction vessel equipped with a stirrer (internal volume: 500 liters) Fully purged with nitrogen gas, ethanol 97.2 kg, iodine 640 g and 6.4 kg of metallic magnesium were charged, and the mixture was reacted under reflux conditions with stirring until no hydrogen gas was generated from the system, to obtain a solid reaction product. The reaction liquid containing the solid reaction product was dried under reduced pressure to obtain a target magnesium compound (a solid catalyst carrier). (2) Adjustment of solid catalyst component A reaction vessel equipped with a stirrer (internal volume 50
0 liters), 30 kg of the magnesium compound (not pulverized), 150 liters of purified heptane (n-heptane), 4.5 liters of silicon tetrachloride, and 5.4 liters of di-n-butyl phthalate were added. While maintaining the inside of the system at 90 ° C., 144 liters of titanium tetrachloride were added thereto with stirring and reacted at 110 ° C. for 2 hours. Then, solid components were separated and washed with purified heptane at 80 ° C. Then add 228 liters of titanium tetrachloride,
After reacting at 110 ° C. for 2 hours, it was sufficiently washed with purified heptane to obtain a solid catalyst component.

(3) Pretreatment Purified heptane 230 was placed in a reaction vessel having an internal volume of 500 liter and equipped with a stirrer.
Liters, 25 kg of the solid catalyst component and triethylaluminum based on titanium atoms in the solid catalyst component.
1.0 mol / mol, dicyclopentyldimethoxysilane 1.
It was fed at a rate of 8 mol / mol. Thereafter, propylene is introduced until the propylene partial pressure reaches 0.3 kg / cm ² G, and at 25 ° C.
The reaction was performed for 4 hours. After the completion of the reaction, the solid catalyst component was washed several times with purified heptane, and further supplied with carbon dioxide and stirred for 24 hours. (4) Polymerization The treated solid catalyst component was added to a polymerization device having a stirrer having an internal volume of 200 liters at a rate of 3 mmol / hr in terms of titanium atoms in the component.
Triethylaluminum is supplied at 4 mmol / kg-PP and dicyclopentyldimethoxysilane is supplied at 1 mmol / kg-PP. The polymerization temperature is 80 ° C and the polymerization pressure (total pressure) is 28 kg / cm ²
G was used to react propylene with ethylene. At this time, the ethylene concentration in the polymerization apparatus was 0.7 mol%, the hydrogen concentration was 3.
4 mol% to achieve the desired ethylene content and molecular weight.

The ethylene concentration and the hydrogen concentration are analysis values of the composition of the gas in the polymerization apparatus by gas chromatogram.

(5) Additive Formulation The following additives were formulated into the propylene copolymer powder thus obtained, and were extruded and granulated by a kneader. 1) Antioxidant Ciba-Geigy's Irganox 1010: 1000 ppm and Ciba-Geigy's Irgafos 168: 1000 ppm 2) Neutralizer Calcium stearate: 1000 ppm 3) Antiblocking agent Silica-based: 1000 ppm 4) Slip agent Erucamide ： 1000 ppm

[2] Propylene random copolymer (B) (1) Preparation of magnesium compound The preparation was carried out in exactly the same manner as in the production of the propylene random copolymer (A). (2) Preparation of solid catalyst component The production was carried out in exactly the same manner as in the production of the propylene-based random copolymer (A) except that diethyl phthalate was used instead of di-n-butyl phthalate. (3) Pretreatment The preparation was carried out in exactly the same manner as in the production of the propylene random copolymer (A) except that cyclohexyldimethoxysilane was used instead of dicyclopentyldimethoxysilane. (4) Polymerization In place of dicyclopentyldimethoxysilane, cyclohexyldimethoxysilane is supplied at 0.1 mmol / kg-PP,
The production was carried out in exactly the same manner as in the production of the propylene-based random copolymer (A) except that the ethylene supply amount and the hydrogen supply amount were adjusted so as to obtain the desired ethylene content and molecular weight. In addition, the compositional analysis value of the gas part in the polymerization apparatus based on the gas chromatogram showed that the ethylene concentration was 5.6 mol% and the hydrogen concentration was 3.2 mol%. (5) Washing 6 L of purified heptane was put into a washing tank with a stirrer having an internal volume of 10 L, and 12 kg of the propylene-based copolymer powder obtained as described above was added thereto.
The washing was carried out for 1 hour under the condition of the rotation speed of the stirring blade of 400 rpm, and the heptane-insoluble portion was separated by filtration. This operation was repeated to obtain a required amount of powder. (6) Formulation of additives The following additives were formulated into the propylene-based copolymer powder thus obtained, and were extruded and granulated by a kneader. 1) Antioxidant Ciba-Geigy Irganox 1010: 1000 ppm and Ciba-Geigy Irgafos 168: 1000 ppm 2) Neutralizing agent Calcium stearate: 1000 ppm 3) Antiblocking agent Silica-based: 2500 ppm 4) Slip agent Erucamide : 300 ppm Propylene random copolymer (A) thus obtained and
The resin properties of the pellet (B) were evaluated by the method (A) described above. Further, the layer configuration (a) was formed by the method (a) described above, and the film quality was evaluated by the method (c). The results are shown in Table 1.

Example 2 The same procedure as in Example 1 was carried out except that the layer structure (b) was formed by the method (A) described above. The results are shown in Table 1. Comparative Example 1 [1] In the production of [1] propylene random copolymer (A) in Example 1, diethyl phthalate was used instead of di-n-butyl phthalate, and cyclohexylmethyldimethoxy was used instead of dicyclopentyldimethoxysilane. A propylene-based random copolymer was produced in the same manner as in Example 1, except that silane was used and the ethylene concentration and the hydrogen concentration during polymerization were set to 1.5 mol% and 3.5 mol%, respectively. This was used as the [1] propylene-based random copolymer of Example 1
Example 1 was repeated except that (A) was used. The results are shown in Table 2. [Comparative Example 2] The same procedure as in Comparative Example 1 was carried out except that the layer structure (b) was formed by the method (A) described above. The results are shown in Table 2.

Comparative Example 3 In the production of [1] propylene-based random copolymer (A) in Example 1, di-phthalic acid
Using diethyl phthalate instead of n-butyl and cyclohexylmethyldimethoxysilane instead of dicyclopentyldimethoxysilane, and supplying cyclohexylmethyldimethoxysilane at 0.1 mmol / kg-PP during polymerization,
A propylene polymer was produced in the same manner as in Example 1 except that polymerization was performed with propylene alone without supplying ethylene. This example was the same as Example 1 except that this was used in place of [1] propylene random copolymer (A) in Example 1. The results are shown in Table 2. [Comparative Example 4] The same procedure as in Comparative Example 3 was carried out except that the (b) layer structure was formed by the method (A) described above. The results are shown in Table 2.

Comparative Example 5 Example 1 was repeated except that the propylene random copolymer (B) was produced by the following method.
Was performed in the same manner as described above. That is, 5.6 g / hr of titanium trichloride, 0.25 mol / hr of diethylaluminum chloride, and 0.01 mol / hr of Irganox 1076 were supplied to a polymerization apparatus having a stirrer having an internal volume of 200 liters.
Propylene and ethylene were reacted at 0 ° C. and a polymerization pressure (total pressure) of 28 kg / cm ² G. At this time, the ethylene concentration in the polymerization apparatus was set to 5.0 mol% and the hydrogen concentration was set to 5.7 mol% so that the desired ethylene content and molecular weight were obtained. In addition,
The ethylene concentration and the hydrogen concentration are analysis values of the composition of the gas portion in the polymerization apparatus based on the gas chromatogram. The polymer obtained by the above polymerization was washed in exactly the same manner as in Example 1 and the propylene-based random copolymer (B), and was formulated by adding additives. The results are shown in Table 2. [Comparative Example 6] The same procedure as in Comparative Example 5 was carried out except that the layer structure (b) was formed by the method (A) described above. The results are shown in Table 2.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

The multilayer film of the propylene-based random copolymer of the present invention has high crystallinity and rigidity in the substrate layer,
In addition, by using a material having a certain degree of low-temperature melting property, etc., and using a material having excellent low-temperature heat sealing property, anti-blocking property, slip property, etc. on at least one surface layer of the base material layer, an unprecedented high level Thus, a film having favorable properties such as good impact resistance, anti-blocking property, slip property, transparency and the like can be provided.

Even if the surface heat-seal layer is thinned, good low-temperature heat-sealability is exhibited, so that the applicable range of the layer ratio can be widened.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C08F 210/06

Claims (3)

(57) [Claims] 1. The following propylene random copolymer (A)
A multilayer film of a propylene-based random copolymer having a surface layer made of the following propylene-based random copolymer (B) on at least one surface of a base material layer made of: [Propylene random copolymer (A)] Propylene random copolymer (A) that satisfies the following (A-1) to (A-6) : Content of ethylene unit in copolymer (A-1) Amount [χa (wt%)]
(A-2) The melt index of the copolymer [MIa (g / 10mi
n)] is 4 to 12 g / 10 min. (A-3) Boiling diethyl ether extraction amount [Ea (wt%)] and χa
Satisfies the relationship of formula (1) Ea ≤ 0.25 χa + 1.1 (1) (A-4) Melting point [Tma (° C)] measured with a differential scanning calorimeter and χa satisfy the relationship of formula (2) Tma ≦ 165 −5 χa (2) (A-5) The isotactic triad fraction [mm fraction a (mol%)] of the PPP chain part measured by ¹³ C-NMR is 98 mol.
l% or more (A-6) the melt index of the copolymer [MIa (g / 10mi
n)] and the frequency ω ₀ = 10 obtained by the frequency dispersion measurement
The relaxation time τ (sec) at ⁰ rad / sec is
Τ ≦ 0.65-0.025 MIa that satisfies the relationship (8) [Propylene random copolymer (B)] Propylene random copolymer (B) satisfying the following (B-1) to (B-6) (B) (B -1) Content of ethylene unit in copolymer [χb (wt%)]
Is 0.2 to 15 wt% (B-2). The melt index of the copolymer [MIb (g / 10mi
n)] is 0.1 to 15 g / 10min. (B-3) Boiling diethyl ether extraction amount [Eb (wt%)] and χb
Eb ≤ 0.2 関係 b + 1.0 (0.2 ≤ χb <5) (3) Eb ≤ 2.0 (5 ≤ χb ≤ 15) (4) (B-4) Tmb ≦ 140 (0.2 ≦ χb <4) (5) Tmb ≦ 160 −5 χb (4) The melting point [Tmb (° C.)] measured by a scanning calorimeter and χb satisfy the relationship of formula (5) or (6). ≦ χb ≦ 15) (6) (B-5) The isotactic triad fraction [mm fraction b (mol%)] of the PPP chain portion measured by ¹³ C-NMR is 90 mol.
l% or more (B-6) Percentage of PEP chain portion measured by ¹³ C-NMR [R
(mol%)] and χb satisfy the relationship of equation (7) R ≧ 0.5 χb + 1.0 (7) 2. The multilayer film of a propylene-based random copolymer according to claim 1, wherein the propylene-based random copolymer (A) satisfies the following (A-7). The content of (A-7) Ethylene units in the copolymer [χa (wt%)] is Ru 1 to 4 wt% der 3. The thickness ratio (surface layer / base material layer) of the surface layer composed of the propylene random copolymer (B) to the substrate layer composed of the propylene random copolymer (A) is 0.005 to 0.5. The multilayer film of the propylene-based random copolymer according to claim 1 or 2, wherein