JPH0527546B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention has excellent low-temperature heat sealing properties,
Moreover, the present invention relates to a polypropylene laminated film having good transparency, blocking resistance, and scratch resistance. Biaxially stretched crystalline polypropylene films are widely used as packaging films due to their excellent transparency and rigidity. However, although it cannot be heat-sealed by itself, it must be heated to a very high temperature, and shrinkage and wrinkles occur, so it cannot be used as is, and resins that can be heat-sealed at a lower temperature. Laminated films coated on one or both sides, laminated, or coextruded are widely used. An important characteristic required of this heat-sealing resin is how far the heat-sealing temperature can be lowered. This is because the lower the heat-sealing temperature, the higher the bag-making temperature of the laminated film can be. Of course, transparency,
It goes without saying that properties such as scratch resistance, blocking resistance, and slipping properties are also important. Although various heat-sealing resins have been proposed in the past, the reality is that there is still no heat-sealing resin that satisfies all of the above characteristics. That is, although polyethylene and ethylene-vinyl acetate copolymers have relatively good low-temperature heat-sealing properties, they are still not at a satisfactory level, and there are problems in that they are inferior in transparency and scratch resistance. The present inventors previously discovered that a specific propylene-α-olefin copolymer exhibits excellent properties as a heat-sealing resin, and filed a patent application (Japanese Patent Application No. 58).
-248302) However, in order to maintain good transparency, blocking resistance, and scratch resistance, and to make the low-temperature heat sealability extremely low, it is necessary to combine the cold xylene soluble portion of the copolymer with the boiling n- It is necessary to increase the content of α-olefin having 4 or more carbon atoms while controlling the heptane insoluble portion within a specific range. However, when it comes to simply increasing the α-olefin content, even in the case of gas phase polymerization, although it is significantly improved compared to the so-called slurry polymerization method in which polymerization is carried out in an inert hydrocarbon, it naturally has its limitations. There is a problem that the higher the α-olefin content, the more difficult the production becomes. On the other hand, JP-A-54-66990 and JP-A-53-114,887 disclose propylene-butene-1 polymerized with a specific catalyst system under conditions that the copolymer dissolves in the liquid phase.
A copolymer is shown, but this copolymer requires that the content insoluble in boiling n-heptane be 5 wt% or less, but the low-temperature heat sealability and transparency are satisfactory. Although it is possible to do so,
The scratch resistance and blocking resistance are extremely poor and it is difficult to put it into practical use. In order to improve this drawback of poor scratch resistance and blocking property, a method of blending a small amount or a large amount of isotactic polypropylene (Japanese Patent Laid-Open No. 56
-58861, JP-A-54-95684) is shown, but
If the amount of isotactic polypropylene blended is small, the above-mentioned drawbacks cannot be solved, and if the amount of blended is large, the advantage of low-temperature heat sealability is lost. In view of the above-mentioned circumstances, the inventors of the present invention have conducted intensive studies to develop a polypropylene laminated film that has extremely excellent low-temperature heat-sealability, transparency, blocking resistance, and scratch resistance. The above polypropylene laminated film is a polypropylene laminated film in which a heat-sealing layer is laminated with a resin composition in which a small amount of a specific copolymer B obtained by a solution polymerization method is blended with a specific copolymer A, which was previously applied for (Japanese Patent Application No. 58-248302). The present invention was completed by discovering that it possesses all of the various characteristics. That is, the present invention relates to a polypropylene laminated film formed by laminating the following resin composition on at least one side of a crystalline polypropylene layer. A random copolymer of propylene and an α-olefin having 4 or more carbon atoms, or a random copolymer of propylene and an α-olefin having 4 or more carbon atoms, obtained by polymerization in a gas phase in the substantial absence of a liquid medium. , the following conditions ~ The content of α-olefin having 4 or more carbon atoms is 7 or more
25 mol% Ethylene content is 5 mol% or less Cold xylene soluble portion is 15 to 50 wt% Boiling n-heptane insoluble portion is 70 to 50 wt% Copolymer A 95 to 55 wt%, propylene, and carbon number of 4 or more A random copolymer with α-olefin of
50 mol% A copolymer that satisfies a cold xylene soluble portion of 30 wt% or more and is obtained by a solution polymerization method.
B is blended with 5 to 45 wt%, and the following conditions are met: α-olefin content of 4 or more carbon atoms is 8 to
35 mol% A resin composition with an ethylene content of 4 mol% or less and a cold xylene soluble portion of 15 to 60 wt%. The first feature of the laminated film obtained by the present invention is that it has excellent transparency, scratch resistance, and blocking resistance, even though it has extremely excellent low-temperature heat sealability. The second feature is that only a small amount of expensive copolymer B obtained by solution polymerization is required. Copolymer A used in the present invention is produced by a so-called gas phase polymerization method. This is because in the generally widely used slurry polymerization method, in which polymerization is carried out in an inert hydrocarbon, a large amount of polymer dissolves in the inert hydrocarbon solvent, making polymerization extremely difficult. Not only is it difficult to obtain, but the polymer yield is significantly reduced, making it economically disadvantageous. Polymerization can be carried out using a known fluidized bed reactor, a fluidized bed reactor equipped with a stirrer, or the like. In addition, polymerization is carried out at a temperature in which the gas does not liquefy in the reactor and the polymer particles do not melt into agglomerates.
It is essential to carry out the polymerization under pressure conditions, and particularly preferred polymerization conditions are a temperature range of 40 to 100°C and a pressure range of 1 to 50 Kg/cm ² (gauge pressure, hereinafter abbreviated as G). Further, for the purpose of controlling the melt fluidity of the obtained polymer, it is preferable to add a molecular weight regulator such as hydrogen. Polymerization can be carried out either by batch polymerization, continuous polymerization, or a combination of the two, and the monomers and molecular weight regulator consumed in the polymerization can be carried out continuously or intermittently. It can be fed to the reactor. Further, after gas phase polymerization, it is also possible to wash with alcohols or hydrocarbon solvents for the purpose of removing catalyst residues or low molecular weight polymers. Copolymer B used in the present invention is produced by a so-called solution polymerization method in which the polymer is polymerized in an inert solvent or under conditions where it is uniformly melted in the polymerization monomer itself. The catalyst system used in the production of copolymer A and copolymer B used in the present invention is a known catalyst for stereoregular polymerization of α-olefin, such as TiCl ₃ ,
A solid catalyst component such as a catalyst whose main component is TiCl ₃ 1/3 AlCl ₃ or a carrier-supported catalyst in which a Ti compound is supported on magnesium chloride, an organoaluminium catalyst, and a third component such as an electron-donating compound. It is a so-called Ziegler-Natsuta catalyst, that is, a catalyst consisting of a transition metal compound of Groups 1 to 1 of the periodic table and an organic compound of a typical metal of group 1 of the periodic table, and the transition metal compound or a catalyst containing the same. Preferably, the components are solids. Preferably, the transition metal compound is a compound containing at least titanium and a halogen, among which the general formula Ti(OR) _o X _no (R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, m is 2 to 4, and n is a number from 0 to m-1). Specific examples of such compounds include TiCl ₄ , TiCl ₃ , TiCl ₂ , Ti(CO ₂ H ₅ )Cl ₃ , Ti
_{( OC6H5} ) _Cl3 , etc. The transition metal compound itself can be the main component or can be used as a catalyst component supported on a suitable carrier. Among titanium halogen compounds, TiCl ₃ is one of the most preferred transition metal compounds in the present invention, but it is known to take α, β, γ, and δ crystal forms, and α- For stereoregular polymerization of olefins, α, γ, and δ types of TiCl ₃ having layered crystallinity are preferred.
TiCl ₃ is generally TiCl ₄ with hydrogen, metallic aluminum,
It is generally obtained as a TiCl ₃ composition by reducing metallic titanium, organoaluminum compounds, organomagnesium compounds, etc. Preferred _TiCl3
The composition is made by reducing TiCl ₄ with metal aluminum and further activating it by mechanical grinding etc.
TiCl ₃ AA and TiCl ₄ are reduced with an organoaluminum compound and further activated using a complexing agent and a halogen compound. In the present invention, the latter is particularly preferred. Also, Ti(OR) ₄ (R is 1 carbon number
to 20 hydrocarbon groups) is reduced with an organoaluminium compound and then converted into an ether compound.
Alkoxy group-containing 3 obtained by treatment with TiCl ₄
Titanium halides can also be suitably used. The TiCl ₃ composition or trivalent titanium halide containing alkoxy groups is combined with diethylaluminum chloride in the presence of hydrogen in liquefied propylene.
Particularly preferred are those capable of producing 6,000 g or more of polypropylene per gram when polymerized at 65° C. for 4 hours. Such a TiCl ₃ composition is disclosed in Japanese Patent Application Laid-Open No. 1987-
Publication No. 34478, Special Publication No. 1982-27085, Special Application No. 1983
It can be produced by the method disclosed in Japanese Patent Application No. 138471/1983, etc. Further, a trivalent titanium halide containing an alkoxy group can be produced by the method disclosed in Japanese Patent Application No. 57-221659. When a transition metal compound is used as a catalyst component supported on a suitable carrier, the carrier may be various solid polymers, especially α-olefin polymers, various solid organic compounds, especially solid hydrocarbons, various solid inorganic compounds, In particular, oxides, hydroxides, carbonates, halides, etc. can be used. Preferred carriers are magnesium compounds, ie, magnesium halides, oxides, hydroxides, hydroxyhalides, and the like. Magnesium compounds can also be used as complexes with other solid substances mentioned above. Although commercially available magnesium compounds can be used as they are, they can be mechanically pulverized, dissolved in a solvent and then precipitated, treated with an electron-donating compound or active hydrogen compound, or treated with an organomagnesium compound such as Grignard reagent. A magnesium compound obtained by decomposing is preferable. In many cases, it is preferable to use these operations in combination to obtain a preferred magnesium compound, and these operations may be carried out in advance when producing the carrier, or may be carried out when producing the catalyst component. Particularly preferred magnesium compounds are halogenated magnesium compounds, and particularly preferred transition metal compounds are the aforementioned halogenated titanium compounds. The supported catalyst component containing titanium, magnesium, and halogen as main components is one of the most preferred catalyst components in the present invention, and is disclosed in JP-A-56-30407, JP-A-57-59915, etc. It can be manufactured by a different method. In order to perform stereoregular polymerization of α-olefin having 3 or more carbon atoms, it is preferable to use a supported catalyst component containing an electron-donating compound and having titanium, magnesium, and halogen as main components. Preferred organic compounds of typical metals in Groups ~ of the Periodic Table are organic compounds of aluminum, particularly those with the general formula R _e AlX _3-e (R is a hydrocarbon group having 1 to 20 carbon atoms, and X is hydrogen or a halogen). Representation,
(e is a number from 1 to 3) is preferred. Specific examples of such compounds include triethylaluminum,
triisobutylaluminum, diethylaluminium chloride, diethylaluminum bromide,
These include ethylaluminum sesquichloride and ethylaluminum dichloride. The most preferred compounds are triethylaluminum, diethylaluminium chloride and mixtures thereof. Examples of electron-donating compounds in the present invention include ethyl acetate, ε-caprolactone, methyl methacrylate, ethyl benzoate, p-ethyl anisate, p-
-Esters or acid anhydrides such as methyl toluate and phthalic anhydride, ether compounds such as di-n-butyl ether, diphenyl ether, and digram, tri-n-butyl phosphite, tripel phosphite, and hexamethylene phosphoric acid. Examples include organic phosphorus compounds such as triamides. In addition, ketones, amines, amides, thioethers, and organosilicon compounds such as alkoxysilanes or aryloxysilanes having Si--O--C bonds can also be used. Further, the solid catalyst component may be one that has been prepolymerized by treating with a small amount of olefin in the presence of an organoaluminum compound or an electron-donating compound before polymerization. Copolymer-A used in the present invention contains a small amount of α-olefin having 4 or more carbon atoms or ethylene as a comonomer. As the α-olefin having 4 or more carbon atoms, butene-1, pentene-1, hexene-1, 4-methylpentene-
Among them, butene-1 is the most preferred because it is difficult to liquefy and can maintain a high partial pressure. If the main component of the comonomer is ethylene or if it contains more than a certain amount of ethylene, problems such as poor transparency or deterioration of film transparency over time, which may be due to bleeding of attic components, may occur. There is a problem with this and it is not desirable. The content of the α-olefin having 4 or more carbon atoms in the copolymer-A used in the present invention is 7 to 25 mol%, more preferably 10 to 23 mol%. When the content of α-olefin having 4 or more carbon atoms is below the lower limit, a large amount of copolymer-B is required to be blended in order to satisfy the low-temperature heat sealing properties of the laminated film, and accordingly Scratch resistance and blocking resistance deteriorate, which is undesirable.
If the upper limit is exceeded, the powder properties will deteriorate when the copolymer is subjected to gas phase polymerization, making stable production difficult, which is not preferable. The ethylene content of copolymer-A used in the present invention is 5 mol% or less, more preferably 3 mol% or less. If the ethylene content exceeds the upper limit, the transparency of the laminated film will deteriorate over time, which is not preferable. The reason for this is not clear, but it is thought that the bleed of the atactic component is the cause. The cold xylene soluble portion (CXS) of copolymer-A used in the present invention is 15 to 50 wt%, more preferably 17 to 40 wt%. When CXS is below the lower limit, it may be difficult to achieve low-temperature heat-sealability in line with the gist of the present invention without increasing the amount of copolymer-B blended, and when producing the copolymer, the polymer This is undesirable as it causes a disadvantage in terms of yield. When CXS exceeds the upper limit, the blocking resistance of the laminated film
It is undesirable that the scratch resistance deteriorates and that when the copolymer is subjected to gas phase polymerization, the powder properties deteriorate and polymerization becomes virtually impossible. The boiling n-heptane insoluble fraction (BHIP) of copolymer-A used in the present invention is 7 to 50 wt%, and 10 to 50 wt%.
40wt% is more preferable. If the BHIP is below the lower limit, the blocking resistance and scratch resistance of the laminated film will deteriorate, which is undesirable. When BHIP exceeds the upper limit, it is difficult to achieve low-temperature heat-sealing properties in line with the gist of the present invention unless the amount of copolymer-B blended is increased, and the scratch resistance and scratch resistance of the laminated film are accordingly reduced. Blocking properties deteriorate, which is not preferable. When the copolymer-A used in the present invention is obtained by gas phase polymerization, it may not be subjected to post-treatment such as a washing step, or it may be subjected to an appropriate washing step,
In any case, it is sufficient that the copolymer used falls within the above specified range. Copolymer-B used in the present invention uses an α-olefin having 4 or more carbon atoms as a comonomer.
As the α-olefin having 4 or more carbon atoms, butene-
1, pentene-1, hexene-1, 4-methylpentene-1, etc. alone or in combination. The content of α-olefin having 4 or more carbon atoms in the copolymer-B used in the present invention is 15 to 50 mol%, more preferably 20 to 45 mol%, and 23 to 40 mol%.
is even more preferable. If the content of α-olefin having 4 or more carbon atoms is below the lower limit, the effect of improving low-temperature heat sealability by blending copolymer-B will be small, which is not preferable. If the content of α-olefin having 4 or more carbon atoms exceeds the upper limit, it is not preferable because even if a small amount is blended into copolymer-A, blocking resistance and scratch resistance will deteriorate. The cold xylene soluble portion (CXS) of copolymer-B used in the present invention is more preferably 30 wt% or more. When CXS is below the lower limit, copolymer-B
The effect of improving low-temperature heat sealability by blending is small, which is not preferable. In the present invention, the blend ratio of copolymer-A and copolymer-B is 95 to 95%.
55wt%, copolymer-B is 5-45wt%, copolymer-A is 93-60wt%, copolymer-B is 7-45wt%.
More preferably, it is 40 wt%, and the copolymer-
More preferably, A is 90 to 70 wt% and copolymer-B is 10 to 30 wt%. If the blending ratio of copolymer-B is below the lower limit, the effect of improving the low-temperature heat-sealability of the laminated film will be small, which is not preferable. If the blending ratio of copolymer-B exceeds the upper limit, the blocking resistance and scratch resistance of the laminated film will deteriorate, which is not preferable. In the present invention, the above-defined copolymer-A
The heat-sealable resin composition obtained by blending Copolymer-B and Copolymer-B must fall within the following specified range. That is, the content of α-olefin having 4 or more carbon atoms is 8 to 35 mol%, more preferably 12 to 30 mol%. Further, the ethylene content is 4 mol% or less,
More preferably, it is 2.5 mol% or less. Furthermore, the cold xylene soluble part (CXS) is 15 to 60 wt%,
More preferably, it is 17 to 50 wt%. The heat-sealable resin composition of the present invention can be obtained by uniformly dispersing it by any known method. Examples include extrusion melt blending method and Banbury blending method. The heat-sealable resin composition of the present invention can also be blended with small amounts of other polymeric substances.
Additionally, additives such as antistatic agents, antiblocking agents, slip agents, and stabilizers can be added. The polypropylene laminated film of the present invention can be obtained by laminating the heat-sealable resin on one or both sides of a crystalline polypropylene film as a base material by a known method. That is, preformed sheets of the base layer and heat-sealable resin layer are passed together between pressure rollers using an adhesive, or the heat-sealable resin is applied as a solution or dispersion in a solvent such as toluene onto the base layer. by coating and laminating, by melt extrusion coating and laminating the heat-sealable resin onto the base layer, or by extruding the heat-sealable resin and the base polymer in separate extruders in a common die or exit where both are still together. The laminated film of the present invention can be obtained by a method of joining while in a molten state. The laminated film of the present invention is preferably uniaxially or biaxially oriented by stretching after lamination. Such polypropylene stretched laminated film is manufactured by the following known method. That is, a method in which a raw laminated sheet is produced by so-called co-pressing, in which both are combined while they are still in a molten state, in or near the exit of an extrusion die for forming the sheet, and then biaxially stretched. A method in which a heat-sealable resin is extruded and laminated onto a polypropylene sheet as a base material, and then biaxially stretched. A method in which a polypropylene sheet as a base material is uniaxially stretched in the MD direction while heated with a roll group including metal rolls, a heat-sealable resin is extruded and laminated onto this sheet, and then stretched in the TD direction, etc. There is. The polypropylene laminated film produced as described above has excellent transparency, blocking resistance, scratch resistance, and slipperiness in addition to having extremely excellent low-temperature heat sealing properties.
Furthermore, it has extremely great practical value because it can be manufactured at low cost. In addition, the data and evaluation in Examples and Comparative Examples were performed according to the following method. (1) α-olefin content in copolymer It was determined from the material balance during production of the copolymer.
Furthermore, the content of butene-1 was determined using an infrared spectrophotometer using a conventional method from characteristic absorption at 770 cm ^-1 to confirm the mass balance results. Note that measurements using an infrared spectrophotometer are based on propylene-butene-
1. Regarding the copolymer, a calibration curve was created and quantified using quantitative values determined by ¹³ C-NMR. (2) Ethylene content in the copolymer It was determined from the material balance during the production of the copolymer.
Furthermore, using an infrared spectrophotometer, 732cm ^-1 and 720cm ^-1
The results of mass balance were confirmed by quantifying the characteristic absorption using a conventional method. In addition, measurements using an infrared spectrophotometer are
A calibration curve was prepared and quantified based on the quantitative values determined by radiation measurement of the ¹⁴ C-labeled ethylene copolymer. (3) Cold xylene soluble part (CXS) Dissolve 5g of polymer in 500ml of xylene, then slowly cool to room temperature. Then, it is left in a bath at 20°C for 4 hours, filtered, and the filtrate is concentrated, dried, dried, and weighed. (4) Boiling n-heptane insoluble part (BHIP) Extract for 14 hours using a Soxhlet extractor. Note that the reflux frequency is once every 5 minutes. BHIP is determined by drying and weighing the extraction residue. (5) Intrinsic viscosity ([η]) Tetralin at 135°C with a concentration of 0.4, 0.2,
Measurements were made at four different points: 0.133 and 0.1 g/dl. (6) Create a 100μ thick press sheet of ΔHaze copolymer,
It was expressed as the difference in haze after annealing at 60°C for 9 hours. (7) Haze value (Haze) Conforms to ASTM-D1003. (8) Heat sealing temperature (H・S・T) Peeling speed of a 25 mm wide sample obtained by pressing the laminated surfaces of films together using a heat sealer at a specified temperature for 2 seconds under a load of 2 kg/cm ² 200
The heat-sealing temperature was defined as the temperature at which the peeling resistance obtained by peeling at a peeling angle of 180° C. was 300 g/25 mm. (9) Blocking Calculate the maximum load (Kg) when shearing and peeling a blocked specimen by treating it at 60℃ for 3 hours under a load of 500g/ ^12cm2 , and display it in Kg/ ^12cm2 . (10) Scratch resistance With the heat-sealable resin layer of the laminated film on the inside, rub vigorously by hand five times. The degree of damage to the inner surface is evaluated in three stages (○, △, ×). Hereinafter, the present invention will be explained 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 Polymerization of copolymer-A (1) Preparation of solid catalyst containing titanium trichloride After purging a 1-volume flask equipped with a stirrer and a dropping funnel with argon, a solution consisting of 60 ml of titanium tetrachloride and 228 ml of N-heptane was prepared. 136.6ml of ethylaluminum sesquichloride and 300ml of n-heptane
ml of the solution was added dropwise over 2 hours at -5 to -10°C. After dropping, stir at room temperature for 30 minutes,
Heat treatment was performed at ℃ for 1 hour. Then, the mixture was allowed to stand at room temperature and subjected to solid-liquid separation, and then washed four times with 400 ml of n-heptane. Next, put 580 ml of n-heptane and 5 ml of diethyl aluminum chloride into the flask, and lower the temperature to 50 ml.
It was kept at ℃. While stirring, add 32 g of propylene to 50
The mixture was gradually fed into the suspension at ℃ for 2 hours to carry out prepolymerization. After treatment, solid-liquid separation and n-heptane
Washing was repeated twice with 400 ml. Next, 392 ml of toluene was charged into the flask, and the temperature was maintained at 85°C. While stirring, add 117 ml of n-butyl ether and 3.7 ml of tri-n-octylamine.
ml was added and reacted at 85°C for 15 minutes. After reaction, iodine
Add a solution of 15.5g dissolved in 196ml of toluene,
The reaction was further carried out at 85°C for 45 minutes. After the reaction, solid-liquid separation was carried out, and once with 500 ml of toluene,
After washing three times with 500ml of n-heptane,
It was dried under reduced pressure to obtain 90 g of a titanium trichloride-containing solid catalyst. The titanium trichloride-containing solid catalyst contained 65.2% by weight of titanium trichloride. (2) Copolymerization Propylene and butene-1 were copolymerized using a fluidized bed reactor with an internal volume of 1 cm ³ equipped with a stirrer. First, 60 kg of propylene-butene-1 copolymer particles for catalyst dispersion were supplied to the reactor, and then the reactor was purged with nitrogen and then with propylene. The pressure was increased to 5 Kg/cm ^{2 G} with propylene, and circulating gas was supplied from the bottom of the reactor at a flow rate of 80 m ³ /hr to keep the polymer particles in a fluidized state, and then the following catalyst was supplied to the reactor. As catalyst components (b) and (c), solutions diluted with heptane were used. (a) 21 g of solid catalyst containing titanium trichloride (b) 112 g of diethylaluminum chloride (c) 11 g of triethyl aluminum (d) 8 g of methyl methacrylate Next, hydrogen concentration was 1.7 vol%, and butene-1 was 17 vol.
% of hydrogen, propylene, and butene-1, increasing the pressure to 10 Kg/ ^cm2G , and increasing the temperature of the fluidized bed to 65%.
The temperature was adjusted to 0.degree. C. to initiate polymerization. During the polymerization, hydrogen, propylene, and butene-1 were supplied so as to keep the concentration and pressure of hydrogen and butene-1 constant. When the amount of polymerization reached 75 kg, 60 kg of polymer particles remained in the reactor for catalyst dispersion in the next polymerization, and the remaining polymer particles were transferred to a stirring mixing tank and 210 g of propylene oxide and 100 g of methanol were added. 30 at 80℃
It was processed separately. It was then dried to obtain a white powdery polymer. The same polymerization was repeated three times and the physical properties of the finally obtained polymer were measured. The intrinsic viscosity of this copolymer is 1.8 dl/g,
Butene-1 content is 14.6 mol% and CXS is
24.8wt%, BHIP is 29.5wt%,
ΔHaze was 0.3%. Polymerization of copolymer B (1) Synthesis of solid catalyst A flask with an internal volume of 500 ml equipped with a stirrer and a dropping funnel was purged with argon, and then replaced with n-heptane.
83 ml, titanium tetrachloride 16.1 ml, and tetra-n-butoxytitanium 51.0 ml were charged into a flask, and the temperature inside the flask was maintained at 20°C while stirring. 162.1ml of n-heptane and diethylaluminum chloride
37.8 ml of the solution was gradually added dropwise from the dropping funnel over 3 hours while maintaining the temperature inside the flask at 20°C. After the dropwise addition was completed, the temperature was raised to 50°C and stirred for 1 hour. Leave to stand at room temperature for solid-liquid separation, and n-heptane
After repeated washing four times with 200 ml, the product was dried under reduced pressure to obtain 64.7 g of a reddish-brown solid product. Next, a 300 ml flask equipped with a stirrer was purged with argon, and then 241 ml of n-heptane, 0.34 g of triethylaluminum, and 19.7 g of the solid product prepared above were charged into the flask, and the temperature was raised to 50 ml.
It was kept at ℃. Next, while stirring, ethylene was gradually supplied into the suspension at 50° C. for 20 minutes while maintaining a partial pressure of 0.2 Kg/cm ² to carry out a preliminary polymerization treatment. After the treatment, the solid-liquid was separated, washed twice with 50 ml of n-heptane, and then dried under reduced pressure. The amount of prepolymerization is 0.09g of polymer per 1g of solid product.
It was hot. Next, a flask with an internal volume of 100 ml was purged with argon, and then 12.1 g of the prepolymerized solid prepared above and 42.3 ml of n-heptane were put into the flask, and the temperature inside the flask was maintained at 30°C. Next, 14.4 ml of di-iso-amyl ether was added, and the mixture was treated at 30°C for 1 hour, and then the temperature was raised to 75°C. Titanium tetrachloride at 75℃
15.7 ml was added and the reaction was carried out at 75°C for 1 hour. After solid-liquid separation, the mixture was repeated four times with 50 ml of n-heptane and then dried under reduced pressure to obtain a solid component. Furthermore, after replacing the flask with an internal volume of 100 ml with argon,
9.9 g of the above solid component and 38 ml of n-heptane were charged into a flask, and the temperature inside the flask was maintained at 30°C. Next, add 8.5 ml of di-iso-amyl ether,
After processing at 30°C for 1 hour, the temperature was raised to 75°C. 11.5 ml of titanium tetrachloride was added at 75°C, and the reaction was carried out at 75°C for 1 hour. After solid-liquid separation, n-heptane 50
After repeating washing four times with ml, drying was carried out under reduced pressure to obtain a solid catalyst component. (2) Copolymerization A 200-inch autoclave is equipped with a stirrer, thermometer, dropping funnel, and reflux condenser, and after reducing the pressure, it is replaced with nitrogen. Pour dry normal heptane 100 into this autoclave and keep it at a constant temperature of 60℃.
This includes 65 mol% propylene and 135 mol% butene.
Flow the mixed gas at a rate of 0.55Ncm ³ /min. Then diethylaluminum chloride as a catalyst
Add 1.0 mol and further add 30 g of the solid catalyst obtained in (1) above to start polymerization. Polymerization was carried out by continuously flowing a mixed gas of propylene and butene-1 for 180 minutes while stirring. Then, the reaction was stopped by adding 3 butanol, and after thorough washing with butanol, the reaction product was poured into a large amount of methanol to precipitate a copolymer. The intrinsic viscosity of this copolymer is 1.8 dl/g, the butene-1 content is 30.5 mol%,
CXS was 67wt%. Preparation of Composition 80 wt% of copolymer-A obtained above and 20 wt% of copolymer-B obtained above were uniformly melt-blended using a 65 extruder. Lamination Processing and Stretching Process The copolymer composition obtained above was laminated onto a 500μ thick sheet of homopolypropylene that had been previously sheet-molded under the following conditions. Lamination equipment: Tanabe 40mm laminator Temperature: 290℃ Die: width 700mm, lip spacing 0.5mm Discharge amount: 200g/min Lamination speed: 9.0m/min Lamination thickness: 50μ Next, from the laminated multilayer sheet 90
A corner sample was taken and a biaxially stretched film was obtained under the following conditions. Stretching machine: Tabletop biaxial stretching machine manufactured by Toyo Seiki Temperature: 150℃ Preheating time: 3 minutes Stretching ratio: MD5x, TD5x Stretching speed: 5m/min The physical properties of the stretched laminated film of about 22μ obtained above were Shown in the table. This stretched laminated film had an extremely low heat-sealing temperature (85° C. or less) and maintained good transparency, blocking resistance, and scratch resistance. Comparative Example 1 Using the copolymer-A obtained in Example 1 itself, a stretched laminated film was obtained under the same conditions as those shown in Example 1. Table 1 shows the physical properties of this stretched laminated film. Although this stretched laminated film had very good transparency, blocking resistance, and scratch resistance, its low-temperature heat-sealability did not satisfy the purpose of the present invention. Comparative Example 2 Copolymer-A and Copolymer-B in Example 1
The blending ratio with copolymer-A45wt%, copolymer-
A stretched laminated film was obtained under the same conditions except that B was changed to 55wt%. Table 1 shows the physical properties of this stretched laminated film. This stretched laminated film uses a large amount of expensive copolymer-B at 55 wt%, which is economically disadvantageous, and the heat sealing temperature is at a level that is not much different from that of Example 1, and it is resistant to blocking. The scratch resistance and scratch resistance were poor, which did not meet the spirit of the present invention. Comparative Example 3 A stretched laminated film was obtained under the same conditions as in Example 1 using commercially available highly crystalline polypropylene (Sumitomo Noblen FA-6312, ^CXS containing 3.3 _wt %). Table 1 shows the physical properties of this stretched laminated film. This stretched laminated film had poor low temperature heat sealability. Comparative Example 4 Highly crystalline polypropylene used in Comparative Example 3
80wt% and the copolymer used in Example 1-
A stretched laminated film was obtained under the same conditions as in Example 1 using a composition of 20 wt% B. Table 1 shows the physical properties of this stretched laminated film. This stretched laminated film still had poor low temperature heat sealability. Comparative Example 5 A stretched laminated film was obtained from the copolymer-B used in Example 1 under the same conditions as in Example 1. This stretched laminated film had good low-temperature heat sealability and transparency, but poor blocking resistance and scratch resistance. 【table】

Claims (1)

[Scope of Claims] 1. A polypropylene laminated film formed by laminating the following resin composition on at least one side of a crystalline polypropylene layer. Propylene and α-olefin having 4 or more carbon atoms,
Or a random copolymer of propylene, an α-olefin having 4 or more carbon atoms, and ethylene, obtained by polymerizing in a gas phase in the substantial absence of a liquid medium, under the following conditions - 4 or more carbon atoms α-olefin content of 7~
25 mol% Ethylene content is 5 mol% or less Cold xylene soluble part is 15 to 50 wt% Boiling n-heptane insoluble part is 7 to 50 wt% Copolymer A 95 to 55 wt%, propylene and carbon number of 4 or more A random copolymer with α-olefin of
50 mol% A copolymer that satisfies a cold xylene soluble portion of 30 wt% or more and is obtained by a solution polymerization method.
B is blended with 5 to 45 wt%, and the following conditions are met: α-olefin content of 4 or more carbon atoms is 8 to
35 mol% Ethylene content is 4 mol% or less Cold xylene soluble portion is 15 to 60 wt% 2. The α-olefin having 4 or more carbon atoms in copolymer A is butene-1 according to claim 1. Polypropylene laminated film.