JP2533321B2 - Polypropylene laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is extremely excellent in low-temperature heat sealability, has excellent transparency, scratch resistance, and hot tack resistance.
The present invention relates to a polypropylene laminated film which has a small amount of hexane solvent extraction (hereinafter abbreviated as solvent extraction amount) and is suitable for food hygiene applications.

<Prior Art> A biaxially stretched film of crystalline polypropylene is widely used as a packaging film because of its excellent transparency and rigidity. However, although it cannot be heat-sealed by itself, it must be heated to an extremely high temperature, and shrinkage and wrinkles occur. Therefore, it is not used as it is and a resin that can be heat-sealed at a lower temperature is used. Laminated films coated or laminated on one or both sides or coextruded are widely used. As a characteristic required for this heat-sealing resin, how much the heat-sealing temperature can be lowered is an important characteristic.
This is because the lower the heat-sealing temperature, the higher the bag-making speed of the laminated film.
However, it is needless to say that the heat-sealing temperature is not only low, but also the properties such as transparency, scratch resistance, and hot tack are important. In addition, when used for food packaging, for example, solvent extraction The amount should be small.

Conventionally, various heat seal resins have been proposed, but the reality is that no heat seal resin satisfies all the above characteristics.

That is, a polypropylene film laminated with polyethylene or an ethylene-vinyl acetate copolymer has relatively good low-temperature heat-sealing properties, but is not yet at a satisfactory level, and has a problem that it is inferior in transparency and scratch resistance. is there. As polypropylene resin, ethylene 5wt
%, There is a propylene-ethylene random copolymer copolymerized, but there is a problem that the transparency, scratch resistance and blocking resistance are excellent, but the low temperature heat sealing property is extremely poor and the hot tack property is poor.

If the content of ethylene to be copolymerized is increased in order to improve the low temperature heat-sealing property of this propylene-ethylene random copolymer, the low temperature heat-sealing property is improved somewhat, but it is not sufficient and the transparency is deteriorated. There is a problem of doing. Among polypropylene resins, the propylene-butene-1 copolymer obtained by copolymerizing butene-1 is
It has long been known as a heat-sealable resin. (BP
-1018341 specification, JP-A-50-128781, JP-A-5
5-17542, JP-A-54-66990, JP-A-53-1
14887, JP-A-56-22307, JP-A-60-1664
However, many of these copolymers are sticky, have poor scratch resistance, and have a large amount of solvent extraction. Further, those having relatively good transparency and scratch resistance and having a small amount of solvent extracted are still unsatisfactory in view of the low-temperature heat-sealing property targeted by the present inventors.

A method of blending a small amount or a large amount of isotactic polypropylene for the purpose of improving the drawbacks of the propylene-butene-1 copolymer (JP-A-56-58861, JP-A-54-48846, JP-A-54-48846). (Sho 54-95684 publication)
However, when the blending amount of isotactic polypropylene is small, the scratch resistance is not sufficiently improved and the solvent extraction amount is large. Also, when the blending amount is large, the advantages of low temperature heat sealability are lost and
From the target level of the present inventor, there are still problems that the hot tack property is poor and the amount of solvent extracted is large.

<Problems to be Solved by the Invention> In view of the above situation, the present inventors have found that all of the outstanding low temperature heat sealability and transparency, scratch resistance, hot tack, and small amount of solvent extraction We have diligently studied to develop a polypropylene laminated film for food packaging, which has both.

<Means for Solving Problems> As a result, specific propylene-random copolymer (A), specific propylene and α-olefin having 4 or more carbon atoms, or propylene and α-olefin having 4 or more carbon atoms. It was found that a polypropylene laminated film obtained by laminating a blend composition in which a copolymer (B) of ethylene and ethylene in a specific ratio is laminated as a heat-sealing layer has all of the above-mentioned characteristics. Was completed.

That is, the present invention provides the following two components (A) and (B) (A) 10 to 90 on at least one surface of the crystalline polypropylene layer.
The present invention relates to a polypropylene laminated film obtained by laminating a resin composition blended at a ratio of wt% (B) of 90 to 10 wt% (however, the amount of n-hexane solvent extracted is 5 wt% or less).

(A) Propylene-random copolymer that satisfies the following conditions: Comonomer content: 4-15 wt% Vicat softening point: 122 ° C or less Cold xylene-soluble part: 15 wt% or less (B) Propylene and Α-olefins having 4 or more carbon atoms,
Or a copolymer of propylene, an α-olefin having 4 or more carbon atoms and ethylene, which satisfies the following conditions 1 to 5: α-olefin having 4 or more carbon atoms: 8 to 35 mol% Ethylene content: 5 Mol% or less Cold xylene soluble part, 15 to 70 wt% ΔHaze 5% or less, n-hexane solvent extraction amount 40 wt% or less The present invention will be described in detail below.

The propylene random copolymer (A) used in the composition of the present invention is well known, and is a crystalline ethylene-propylene random copolymer or ethylene-butene-1.
-Propylene random terpolymer, etc., with a comonomer content of 4-15 wt%.

Propylene random copolymer (A) in the present invention
The Vicat softening point of (hereinafter abbreviated as copolymer (A)) is
The temperature is 122 ° C or lower, preferably 120 ° C or lower. When the copolymer (A) having a Vicat softening point exceeding the upper limit is used, the hot-tack property is deteriorated, and in order to lower the heat seal temperature to the target level of the present invention, the copolymer to be blended is used. The amount of (B) becomes very large, which results in poor blocking resistance, scratch resistance, slippage, and large solvent extraction amount, which is not preferable. The present inventors have discovered that the Vicat softening point of the copolymer (A) is
If the temperature is 122 ° C or lower, surprisingly, in the composition with the specific copolymer specified by the copolymer (B), the heat seal temperature determined based on the heat seal temperatures of both the Also has a much lower heat seal temperature.

The cold xylene-soluble part (hereinafter abbreviated as CXS) of the copolymer (A) in the present invention is 15 wt% or less, preferably 13 wt% or less, and more preferably 10 wt% or less. When CXS exceeds the upper limit, the amount of solvent extracted becomes large, which is not preferable.

Propylene used in the composition of the present invention and α-olefin having 4 or more carbon atoms, or propylene and α having 4 or more carbon atoms
-The copolymer (B) of olefin and ethylene (hereinafter, abbreviated as "copolymer (B)") is produced by a solvent polymerization method of polymerizing in a solvent or a gas phase polymerization method of polymerizing in a gas phase. However, the gas phase polymerization method in which the polymerization is carried out under the condition that the liquid solvent is not substantially present makes it easy to obtain the copolymer (B) suitable for the present invention (having a suitable cold xylene-soluble portion). In addition, since the polymer drying step or the solvent refining step is omitted or greatly simplified, it is economically excellent and preferable.

When producing by gas phase polymerization, it can be carried out by a known fluidized bed reactor, a fluidized bed reactor with a stirrer or the like. Also, the polymerization does not liquefy the gas in the reactor,
Moreover, it is essential to carry out the reaction under the conditions of temperature and pressure at which polymer particles do not melt and agglomerate. Preferred polymerization conditions include a temperature range of 40 to 100 ° C and a pressure of 1 to 50 Kg / cm ² (gauge pressure,
Hereinafter abbreviated as G. ) Pressure range, 50 ~ 80 ℃, 2 ~ 20Kg /
cm ² G is more preferred. Further, for the purpose of controlling the melt fluidity of the obtained polymer, it is preferable to add a molecular weight modifier such as hydrogen. Polymerization can be carried out by either batch polymerization, continuous polymerization, or a combination of both methods, and the monomer and molecular weight regulator consumed in the polymerization can be continuous or intermittent. Can be fed to the reactor. In addition, the copolymer is preferably a random copolymer in which a monomer and a comonomer are simultaneously supplied in a constant composition for polymerization, but it is also possible to change the composition of the monomer to be polymerized stepwise and continuously. it can. After the polymerization, the obtained copolymer can be washed with alcohols or a hydrocarbon solvent for the purpose of removing the fusing medium residue or the low molecular weight polymer.

The catalyst system used for producing the copolymer (B) used in the composition of the present invention is a known catalyst for stereoregular polymerization of α-olefin, that is, a so-called Ziegler-Natta catalyst, that is, the periodic table It comprises a transition metal compound of group IV to VIII, an organic compound of a typical metal of group I to III of the periodic table, and a third component such as an electron donating compound. The transition metal compound or a catalyst component containing the same Is preferably a solid.

TiCl ₃ is a transition metal compound, but α, β, γ,
It is known to have δ-type and δ-type crystallinity. In order to stereoregularly polymerize α-olefins having 3 or more carbon atoms, α-, γ-, and δ-type TiCl ₃ having layered crystallinity can be used.
Is preferred. TiCl ₃ is generally obtained as a TiCl ₃ composition by reducing TiCl ₄ with hydrogen, metallic aluminum, metallic titanium, an organic aluminum compound, an organic magnesium compound, or the like. A preferred TiCl ₃ composition is so-called TiCl ₃ · AA, which is obtained by reducing TiCl ₄ with metallic aluminum and further activated by mechanical grinding, etc., and reducing TiCl ₄ with an organoaluminum compound, and further adding a complexing agent and a halogen compound. The activated TiCl ₃ composition is more preferred.
Further, Ti (OR) nX ₄ -n (R represents a hydrocarbon group having 1 to 20 carbon atoms, n represents a number of 0 to 4) is reduced with an organoaluminum compound, and then an ether compound and Ti
An alkoxy group-containing trivalent titanium halogenated product obtained by treating with Cl ₄ can be more preferably used.

A TiCl ₃ composition or an alkoxy group-containing trivalent titanium halide is to be combined with diethylaluminum chloride in the presence of hydrogen in liquefied propylene and polymerized at 65 ° C for 4 hours to produce 6,000 g or more of polypropylene per 1 g. Those capable of satisfying are preferable. Take TiCl ₃
The composition can be produced by the methods disclosed in JP-A-47-34478, JP-B-55-27085, JP-A-57-26508 and JP-A-58-138471. Further, an alkoxy group-containing trivalent titanium halide is disclosed in JP-A-59-59
It can be produced by the method disclosed in JP-A-126401 or JP-A-60-228504.

When a transition metal compound is used as a catalyst component supported on a suitable simple substance, the solid substance may be various solid polymers, particularly α-olefin polymers, various solid organic compounds, particularly solid hydrocarbons, various solid inorganic compounds, In particular, oxides, carbonates and halides can be used. Preferred carriers are magnesium compounds, ie magnesium halides, oxides, hydroxides, hydroxyhalides and the like. The magnesium compound can be used as a complex with other solid substances mentioned above. Commercially available magnesium compounds may be used as they are, but they may be mechanically pulverized, dissolved in a solvent and then precipitated, or treated with an electron-donating compound or an active hydrogen compound, or an organic compound such as a Grignard reagent. A magnesium compound obtained by decomposing a magnesium compound is preferable. In many cases, the operations for obtaining these preferable magnesium compounds are preferably used in combination, and these operations may be carried out at the time of producing the carrier in advance or at the time of producing the catalyst component. A particularly preferred magnesium compound is a halogen compound of magnesium, and a particularly preferred transition metal compound is the halogen compound of titanium described above. Such titanium, magnesium,
A supported catalyst component containing halogen as a main component is one of the more preferable catalyst components in the present invention.
It can be produced by the method disclosed in JP-A No. 30407, JP-A No. 57-59915, or the like. In the present invention, of these, the catalyst component with a carrier containing an electron-donating compound and containing titanium, magnesium and halogen as the main components is one of the more preferable catalyst components.

A composite catalyst containing titanium, magnesium, halogen, or an electron-donating compound as a main component, which is not a carrier-supported type, is also one of the more preferable catalyst components in the present invention. It can be produced by the method disclosed in Japanese Patent Application No. 60-59792.

An organic compound of aluminum is preferable as an organic compound of a typical metal of Group I to III of the periodic table, and particularly, an organic compound of the general formula reAl X ₃ -e (R is a hydrocarbon group having 1 to 20 carbon atoms, X is hydrogen). , Or halogen, and e is a number of 1 to 3). Specific examples of such compounds include triethyl aluminum, triisobutyl aluminum, diethyl aluminum hydride, diethyl aluminum chloride, diethyl aluminum bromide, ethyl aluminum sesquichloride, ethyl aluminum dichloride and the like. The most preferred compound is triethylaluminum,
Diethyl aluminum chloride, and mixtures thereof.

Examples of the electron-donating compound in the present invention include ethyl acetate, ε-caprolactone, methyl methacrylate, ethyl benzoate, ethyl p-anisate, methyl p-toluate, esters such as phthalic anhydride, or acid anhydrides, diacids, and the like. Examples thereof include ether compounds such as -n-butyl ether, diphenyl ether, and digram, and organic phosphorus compounds such as tri-n-butyl phosphite, triphenyl phosphite, and hexamethylene phosphoric triamide. In addition, ketones, amines, amides, thioethers, alkoxysilanes having a Si—O—C bond, or organosilicon compounds such as aryloxysilane can be used. The solid catalyst component may be preliminarily polymerized by treating with a small amount of olefin in the presence of an organoaluminum compound or an electron donating compound prior to the vapor phase polymerization. I don't care.

The copolymer (B) used in the composition of the present invention comprises an α-olefin having 4 or more carbon atoms or ethylene as a comonomer in a very small amount in combination, and an α-olefin having 4 or more carbon atoms is butene- 1, pentene-1, hexene-
Examples thereof include 1,4-methylpentene-1 and the like alone or in combination, but for example, butene-1 is most preferable because it can take a high partial pressure because it is difficult to liquefy when gas phase polymerization is carried out.

Copolymer (B) used in the composition of the present invention has 4 carbon atoms
The above α-olefin content was 8 to 35 mol%,
-30 mol% is preferable, and 12-28 mol% is more preferable.
If the α-olefin content of 4 or more carbon atoms is below the lower limit, the effect of improving the low temperature heat-sealing property of the laminated film is insufficient, which is not preferable, and if it exceeds the upper limit, the scratch resistance of the laminated film is increased. Is worse, and the amount of solvent extracted is large, which is not preferable.

The ethylene content of the copolymer (B) used in the composition of the present invention is 5 mol% or less, preferably 3 mol% or less. When the ethylene content exceeds the upper limit, the transparency of the laminated film deteriorates with time, which is not preferable. The reason for this is not clear, but the bleeding of the atactic component seems to be the cause.

The CXS of the copolymer (B) used in the composition of the present invention is 15
Is about 70 wt%, preferably 16 to 50 wt%, more preferably 16 to 40 wt%, and even more preferably 16 to 35 wt%. If the CXS is below the lower limit, the effect of improving the low temperature heat-sealing property and the hot tack property of the laminated film is insufficient, which is not preferable.
If the upper limit is exceeded, the scratch resistance of the laminated film will be poor and the amount of solvent extracted will be large, such being undesirable.

ΔHaze of copolymer (B) used in the composition of the present invention
Is 5% or less, preferably 4% or less, and more preferably 3% or less. When ΔHaze exceeds the upper limit, the good effect of the low temperature heat sealability of the laminated film becomes insufficient, and the phenomenon of deterioration of transparency with time occurs, which is not preferable.

The solvent extraction amount of the copolymer (B) used in the composition of the present invention is 40 wt% or less, preferably 20 wt% or less. If the solvent extraction amount is less than the upper limit, the solvent extraction amount of the composition can be increased even if the blending ratio of the copolymer (B) is increased at the time of blending with the copolymer (A) or the like. ， There is an advantage that can be reduced.

The copolymer (B) used in the composition of the present invention is preferably not decomposed by an organic peroxide or the like before preparing the composition. This is because if the copolymer (B) is specified as described above, the method of decomposition granulation as disclosed in JP-A-61-248740 becomes unnecessary. Further, when the copolymer (B) is obtained, for example, by a gas phase polymerization method, it is obtained in a powder form, and therefore, if it is not decomposed and granulated before preparation of the composition as in the preferred embodiment of the present invention, a powder form is obtained. In addition, it can be used for preparing a composition, and has an advantage that additives and the like can be well dispersed.

In the preparation stage of the composition, the melt index of the composition can be appropriately prepared by performing decomposition granulation with an organic peroxide or the like.

The composition used in the present invention contains the copolymer (A) in an amount of 10 to 90
It is obtained by blending wt% and copolymer (B) 90 to 10 wt%, and blending copolymer (A) 15 to 85 wt% and copolymer (B) 85 to 15 wt% preferable.

If the blending amount of the copolymer (A) exceeds the upper limit, the blending amount of the copolymer (B) must be reduced, and as a result, low temperature heat sealability cannot be achieved, which is not preferable. When the blending amount of the copolymer (A) is below the lower limit, the copolymer (B)
Inevitably the amount of solvent extraction must be increased,
Not preferred. Further, the solvent extraction amount of the resin composition used in the present invention is 5 wt% or less.

The melt index (g / 10min) of the composition blended as described above is preferably 0.5 to 50g / 10min. If the melt index is below the lower limit, the workability will be poor, and if it is above the upper limit, the heat seal strength will be poor, which is not preferable.

In the present invention, the above composition can be obtained by uniformly dispersing it by any known method. For example, an extrusion melt blending method, a Banbury blending method, and the like. It is also possible to obtain the above composition by a so-called multi-stage polymerization method in which the polymerization conditions are changed stepwise.

Additives such as antistatic agents, antiblocking agents, slip agents, stabilizers and nucleating agents can be added to the composition of the present invention.

The polypropylene laminated film of the present invention can be obtained by laminating the heat-sealable resin composition on one side or both sides of the crystalline polypropylene film serving as a substrate by a known method. That is, a method in which a preformed sheet of a base layer and a heat-sealable resin layer is passed together between pressure rollers using an adhesive, the heat-sealable resin is a solution of a solvent such as toluene, or a base layer as a dispersion. Method of coating and laminating on top, method of laminating heat-sealable resin on substrate layer by melt extrusion coating method, or extruding heat-sealable resin and substrate polymer by separate extruders, in common die or at outlet Then, the laminated film of the present invention can be obtained by the method of joining the both in a molten state.

In the laminated film of the present invention, the heat-sealable resin layer is preferably oriented in at least uniaxial direction. Such a polypropylene stretched laminated film is manufactured by the following known method. That is, in the extrusion die for forming the sheet, or in the vicinity of the outlet, a raw fabric laminated sheet is produced by so-called co-extrusion, in which both are compounded in a molten state, and then biaxially stretched. Heat-sealable resin is extrusion-laminated on the polypropylene sheet of the base material,
After that, biaxial stretching method. A base polypropylene sheet is uniaxially stretched in the MD direction with a roll group including a metal roll in advance, and heat-sealable resin is extrusion-laminated on this sheet, and then stretched in the TD direction. There are ways.

The polypropylene laminated film produced as above has excellent transparency, good transparency, good scratch resistance and hot tack, and has a good solvent extraction amount, even though it has remarkably excellent low temperature heat sealability. It is extremely small, suitable for food hygiene, and has extremely great practical value that it can be manufactured at low cost.

The data and evaluation in the examples and comparative examples are as follows.
It was performed according to the following method.

(1) α-Olefin content in copolymer It was determined from the mass balance. Moreover, the content of butene-1 was further quantified by an ordinary method from the characteristic absorption at 770 cm ^-1 using an infrared spectrophotometer, and the result of the mass balance was confirmed. In the measurement with the infrared spectrophotometer, a propylene-butene-1 copolymer was quantified by preparing a calibration curve from the quantitative value by ¹³ C-NMR.

(2) Ethylene content in copolymer Obtained from the mass balance. Furthermore, using an infrared spectrophotometer, the results of mass balance were confirmed by quantifying by the conventional method from the characteristic absorption at 732 cm ^-1 , -720 cm ^-1 . The infrared spectrophotometer was used for quantification by preparing a calibration curve based on the quantified values of ¹⁴ C-labeled ethylene copolymer measured by radiation.

(3) Melt index (MI) according to ASTM-D1238 (4) Vicat softening point (VSP) according to ASTM-D1525 (5) Cold xylene soluble part (CXS) Dissolve 5 g of polymer in 500 ml of xylene and then to room temperature. Slowly cool. Then, after leaving it in a bath at 20 ° C for 4 hours, it is passed, the liquid is concentrated, dried, dried and weighed.

(6) Intrinsic viscosity ([η]) Tetralin at 135 ℃, the concentration was adjusted to 0.4, 0.2, 0.133,
And 0.1 g / dl were changed at 4 points for measurement.

(7) A press sheet having a thickness of 100 μm of ΔHaze copolymer was prepared, and expressed as the difference between the haze after annealing treatment at 60 ° C. for 9 hours and the haze before treatment.

(8) Solvent extraction amount This is the n-hexane extraction amount at 50 ° C specified in FDA §177 ・ 1520.

(9) Haze value (Haze) Compliant with ASTM-D1003 (10) Heat sealing temperature Use a heat sealer between the laminated surfaces of the film
2Kg / cm at the specified temperature² Load and crimp for 2 seconds.
The sample with a width of 25 mm obtained by the above was peeled at a peeling speed of 200 mm / min and a peeling angle of 18 mm.
When the peel resistance obtained by peeling at 0 ° is 300g / 25mm
Was used as the heat sealing temperature.

(11) Scratch resistance With the heat-sealing resin layer of the laminated film inside,
Rub vigorously 5 times with your hands. The degree of scratches on the inner surface is evaluated in three grades (○, △, ×).

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples unless the gist thereof is exceeded.

Example 1 (1) Synthesis of solid product A flask having an inner volume of 500 ml equipped with a stirrer and a dropping funnel was replaced with argon, and then 83 ml of n-heptane, 16.1 ml of titanium tetrachloride, and 51.0% of tetra-n-butoxytitanium. Add ml to the flask and adjust the temperature in the flask to 20 with stirring.
It was kept at ℃. A solution consisting of 162.1 ml of n-heptane and 37.8 ml of diethylaluminum chloride was gradually added dropwise from the dropping funnel over 3 hours while maintaining the temperature in the flask at 20 ° C. After the dropping was completed, the temperature was raised to 50 ° C. and the mixture was stirred for 1 hour. The mixture was left standing at room temperature for solid-liquid separation, washed 4 times with 200 ml of n-heptane, and then dried under reduced pressure to give a reddish brown solid product 6
4.7 g were obtained.

(2) Synthesis of pre-polymerized solid After a flask with a capacity of 300 ml equipped with a stirrer was purged with argon, n-heptane 241 ml and triethylaluminum 0.1.
34 g and 19.7 g of the solid product prepared in (1) above were charged into a flask and the temperature was kept at 50 ° C. Next, while stirring and maintaining ethylene at a partial pressure of 0.2 Kg / cm ² , ethylene was gradually fed into the suspension at 50 ° C. for 20 minutes to carry out a prepolymerization treatment. After the treatment, solid-liquid separation was performed, washing with 50 ml of n-heptane was repeated twice, and then drying under reduced pressure. Prepolymerization amount is 1g of solid product
The weight of the polymer was 0.09 g.

(3) Synthesis of solid catalyst component After replacing the flask with an internal volume of 100 ml with argon, 12.1 g of the prepolymerized solid prepared in (2) above and 42.3 ml of n-heptane were put into the flask, and the temperature in the flask was adjusted to 30.
It was kept at ℃. Next, 14.4 ml of di-iso-amyl ether was added, and the mixture was treated at 30 ° C for 1 hour and then heated to 75 ° C. 75
Titanium tetrachloride (15.7 ml) was added at ℃ and reacted at 75 ℃ for 1 hour. After solid-liquid separation, washing with 50 ml of n-heptane was repeated 4 times, followed by vacuum drying to obtain a solid component. Furthermore, after replacing the flask with an internal volume of 100 ml with argon,
The solid component (9.9 g) and n-heptane (38 ml) were charged into the flask, and the temperature inside the flask was maintained at 30 ° C. Next, 8.5 ml of di-iso-amyl ether was added, and the mixture was treated at 30 ° C for 1 hour and then heated to 75 ° C. Titanium tetrachloride (11.5 ml) was added at 75 ° C, and the reaction was carried out at 75 ° C for 1 hour. After solid-liquid separation, washing with 50 ml of n-heptane was repeated 4 times, followed by drying under reduced pressure to obtain a solid catalyst component.

(4) Copolymerization (Copolymer (B)) Propylene butene-1 was copolymerized using a fluidized bed reactor with an internal volume of 1 m ³ equipped with a stirrer. First, 60 parts of propylene-butene-1 copolymer particles for catalyst dispersion were placed in a reactor.
The reactor was purged with nitrogen and then with propylene. Pressure up to 5 Kg / cm ² G with propylene, 80 m
Circulating gas was supplied from the bottom of the reactor at a flow rate of ³ / hr to keep the polymer particles in a fluidized state, and then the catalyst shown below was supplied to the reactor. As the catalyst components (b) and (c), a solution diluted with heptane was used.

(A) Solid catalyst component 21g (b) Diethyl aluminum chloride 156g (c) Triethylaluminum 22g (d) Methyl methacrylate 15g Then hydrogen, propylene, butene-1 so that the hydrogen concentration is 1.7vol%, butene-1 29vol%. Supply 10 kg / cm
^The pressure was raised to ² G and the temperature of the fluidized bed was adjusted to 70 ° C to initiate polymerization. Hydrogen, propylene and butene-1 were supplied so that the concentrations of hydrogen and butene-1 and the pressure were kept constant during the polymerization. When the amount of polymerization reached 75 Kg, 60 Kg of polymer particles were left in the reactor for catalyst dispersion for the next polymerization, the remaining polymer particles were transferred to a stirring and mixing tank, and 210 g of propylene oxide and 100 g of methanol were added. And treated at 80 ℃ for 30 minutes. Then, it was dried to obtain a white powdery polymer. The same polymerization was repeated 3 times, and the physical properties of the finally obtained polymer (copolymer (B)) were measured. Butene-1 content is
20.3 mol%, CXS 23.9%, ΔHaze 0.9%, solvent extraction 7.3%, intrinsic viscosity 1.8dl / g.

(5) Composition Preparation Copolymer (A) Sumitomo Noblene RW160 was used. RW160 ethylene
Content is 4.8wt%, Vicat softening point is 118 ℃
The melt index is 8.8g / 10 minutes, and CXS is 4.3%.
Met.

70 wt% of the above copolymer (A) and 30 wt% of the copolymer (B) obtained in (4) were subjected to uniform melt blending with a 65φ extruder.

In addition, 0.2 PHR of BHT was added as an antioxidant, 0.2 PHR of silica was added as an anti-blocking agent, and 0.2 PHR of stearic acid amide was added as a lubricant.

(6) Lamination and Stretching The composition obtained in (5) was laminated by a press molding method onto a homopolypropylene sheet having a thickness of 500 µ so that the composition layer had a thickness of 100 µ. (The thickness of the laminated sheet is 600 μ) Next, a 90-square sample was taken from the laminated sheet to obtain a biaxially stretched film under the following conditions.

Stretching machine: Tabletop biaxial stretching machine manufactured by Toyo Seiki Temperature: 150 ℃ Preheating time: 3 minutes Stretching ratio: MD5 times, TD5 times Stretching speed: 5 m / min Composition of physical properties of the laminated stretched film of about 24μ thickness obtained above The physical properties are shown in Table 1. This laminated stretched film was excellent in transparency, scratch resistance, etc., even though the heat sealing temperature was extremely low. or,
The solvent extraction amount of the composition used for the sealant layer is small,
It was good.

Example 2 Copolymer (A) and copolymer (B) used in Example 1
A laminated stretched film was obtained under the same conditions as in Example 1 except that the compounding ratio in the composition preparation was changed by using the same one. The blending ratio, the physical properties of the composition, and the physical properties of the laminated stretched film are shown in Table 1.

This laminated stretched film had good properties as in Example 1.

Examples 3 and 4 (1) Polymerization of copolymer (B) The same polymerization conditions as in Example 1 were used, except that the catalyst system used in Example 1 was used and the amount of butene-1 charged was changed. To obtain a copolymer. Butene-1 of the obtained copolymer (B)
The content is 15.8 mol%, CXS is 19.5 wt%, ΔHaze is 0.4%,
The amount of solvent extracted was 6.2% and the intrinsic viscosity was 1.8 dl / g.

(2) Preparation of composition and production of laminated film Copolymer
(A) Sumitomo Noblen FL6711N was used. FL6711N
Ren content is 6.2wt%, Vicat softening point is 109 ℃, melt
The index was 5.5 g / 10 min and CXS was 9.5 wt%. the above
Using copolymer (A) and copolymer (B), Table 1
In addition to the composition ratios shown in the composition preparation,
A laminated stretched film was obtained under the same conditions as in 1.

This laminated stretched film had good properties as in Example 1.

Example 5 (1) Polymerization of Copolymer (B) Using the catalyst system used in Example 1, except that the amount of butene-1 charged was changed and the polymerization pressure was changed to 7 kg / cm ² G, A copolymer was obtained under the same polymerization conditions as in Example 1. The obtained copolymer (B) had a butene-1 content of 25.1 mol% and CXS of 3
5.1wt%, ΔHaze 1.6%, solvent extraction 15.5%, intrinsic viscosity 2.0dl / g.

(2) Preparation of composition and production of laminated film Copolymer (A) The same as in Example 1 was used.

A laminated stretched film was obtained under the same conditions as in Example 1 except that the mixing ratio was 85 wt% of the copolymer (A) and 15 wt% of the copolymer (B) obtained from (1).

This laminated stretched film had good properties as in Example 1.

Example 6 (1) Polymerization of Copolymer (B) In the catalyst system used in Example 1, triethylaluminum was omitted and the amount of methyl methacrylate was 8 g.
Butene-1 using the same catalyst system except that
A copolymer was obtained under the same polymerization conditions as in Example 1 except that the charging amount was changed and ethylene was newly introduced. The resulting copolymer (B) had a butene-1 content of 16.1 mol%, an ethylene content of 2.0 mol%, a CXS of 24.5 wt%, a ΔHaze of 1.3%, a solvent extraction amount of 12.5%, and an intrinsic viscosity number of It was 2.0 dl / g.

(2) Preparation of composition and production of laminated film Copolymer (A) The same as in Example 1 was used.

A laminated stretched film was obtained under the same conditions as in Example 1 except that the mixing ratio was 70 wt% of the copolymer (A) and 30 wt% of the copolymer (B) obtained from (1).

This laminated stretched film had good properties as in Example 1.

Comparative Example 1 (1) Preparation of composition and production of laminated film Copolymer (A) Sumitomo Noblene RW140 was used. RW140 ethylene
Content is 3.7wt%, Vicat softening point is 125 ℃
The melt index is 8.3g / 10 minutes, and CXS is 3.8%.
Is.

 Copolymer (B) The same as in Example 1 was used.

70 wt% of the above copolymer (A), 30 wt of the above copolymer (B)
A laminated stretched film was obtained under the same conditions as in Example 1 except that the blending ratio was changed to%.

It can be seen that the low-temperature heat-sealing property of this laminated stretched film is extremely poor when compared with Example 1. This means that the range specified in the present invention can produce a very specific effect when selecting the copolymer (A).

Comparative Example 2 (1) Preparation of Composition and Preparation of Laminated Film Copolymer (A), Copolymer (B) The same as in Example 1 was used.

95% by weight of the above copolymer (A), 5% by weight of the above copolymer (B)
A laminated stretched film was obtained under the same conditions as in Example 1 except that the blending ratio was changed to%. This laminated stretched film is inferior in low-temperature heat sealability, which is not preferable.

Comparative Example 3 (1) Preparation of composition and production of laminated film Copolymer (A) The same as in Example 1 was used.

Copolymer (B) Obtained by a slurry polymerization method using n-heptane as a solvent, which is a propylene-butene-1 copolymer from which components soluble in n-heptane have been removed and which contains butene-1. The amount is 15.1 mol%, CXS is 10.1 wt%, ΔHaze is 0.5%, solvent extraction is 3.0 wt%, and intrinsic viscosity is 1.9 dl / g.

70 wt% of the above copolymer (A), 30 wt of the above copolymer (B)
A laminated stretched film was obtained under the same conditions as in Example 1 except that the blending ratio was changed to%. This laminated stretched film is inferior in low-temperature heat sealability, which is not preferable.

Comparative Example 4 (1) Preparation of composition and production of laminated film Copolymer (A) Sumitomo Noblene RW120 was used. RW120 ethylene
Content is 2.3wt%, Vicat softening point is 137 ℃
The melt index is 9.1g / 10 minutes and CXS is 3.2%.
Is.

 Copolymer (B) Mitsui Petrochemical Tuffmer XR110T propylene tube
Ten-1 random copolymer was used. Tuffmer XR11
Butene-1 content of 0T is 26.5mol%, CXS is 62wt%, ΔHa
ze is 2.5%, solvent extraction is 69wt%, intrinsic viscosity is 1.8dl / g
Is.

40 wt% of the above copolymer (A), 60 wt of the above copolymer (B)
A laminated stretched film was obtained under the same conditions as in Example 1 except that the blending ratio was changed to%. Although this laminated stretched film is satisfactory in low temperature heat sealability, it is not preferable because it has poor scratch resistance and a large amount of solvent is extracted as the composition used for the sealant layer.

Comparative Example 5 Using the copolymer (B) itself used in Example 3, a laminated stretched film was obtained under the same conditions as in Example 1.
This laminated stretched film is not preferable because the amount of solvent extracted from the composition used for the sealant layer is large.

Comparative Example 6 Using the copolymer (A) itself used in Example 1, a laminated stretched film was obtained under the same conditions as in Example 1. This laminated stretched film had extremely poor low temperature heat sealability.

<Effects of the Invention> The present invention is remarkably excellent in low-temperature heat sealability,
It also has excellent transparency, scratch resistance, and hot tack resistance.
Moreover, a laminated film having a small amount of solvent extraction was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Yoshi ▼ Teruaki Tada 5-1 Anezaki Kaigan, Ichihara City Inside Sumitomo Chemical Co., Ltd. (56) References JP-A-56-58861 (JP, A) JP-A-SHO 55-14223 (JP, A) JP-A-55-3443 (JP, A) JP-A-54-162785 (JP, A) JP-A-61-169246 (JP, A) JP-A-61-84242 (JP, A) A)

Claims (2)

(57) [Claims] 1. The following two components (A) and (B) are added to at least one surface of the crystalline polypropylene layer (A) in an amount of 10 to 90 wt.
%, (B) 90 to 10 wt% of a blended resin composition (provided that the amount of n-hexane solvent extracted is 5 wt% or less) is laminated to form a polypropylene laminated film for food packaging. (A) Propylene-random copolymer satisfying the following conditions: comonomer content: 4-15 wt% Vicat softening point: 122 ° C. or lower Cold xylene-soluble part: 15 wt% or lower (B) Propylene and Α-olefins having 4 or more carbon atoms,
Or a copolymer of propylene, an α-olefin having 4 or more carbon atoms, and ethylene, which satisfies the following conditions: α-olefin having 4 or more carbon atoms is 8 to 35 mol%, ethylene content is 5 Mol% or less Cold xylene soluble part is 15 to 70 wt% ΔHaze is 5% or less n-hexane solvent extraction amount is 40 wt% or less 2. The polypropylene laminated film for food packaging according to claim 1, wherein the resin composition layer is stretched at least uniaxially.