JPS60152516A - Packaging film - Google Patents

Abstract

PURPOSE:A packaging film which is flexible and excellent in transparency and gloss, having blocking resistance and can be produced at low cost, comprising a specified random copolymer having a specified cold xylene-soluble portion content and a specified boiling n-heptane-insoluble potion content. CONSTITUTION:A packaging film comprising a copolymer of (A) propylene with (B) a 4C or higher alpha-olefin (e.g., butene-1) wherein the content of component B is 10-25mol%, the boiling n-heptane-insoluble portion content of the copolymer is 7wt% or above, and the cold xylene-soluble portion content is 13-60wt%. The yields of the produce are high, and in addition it can be made from a resin which can be produced at low cost, and this packaging film is flexible and excellent in transparency and gloss and also excellent in blocking resistance.

Description

Detailed Description of the Invention The present invention provides a packaging film that is flexible, has excellent transparency and gloss, and has excellent blocking resistance, and is made from a propylene copolymer that has a high product yield and is produced at low cost. Regarding.

Vinylon film has been used for many years in the packaging film field, especially in the textile packaging film field. This is because vinylon film is flexible, has excellent transparency and gloss, and gives textile products a luxurious feel. However, disadvantages of vinylon film include that it is greatly affected by humidity, its properties vary widely depending on the season, such as being too soft during the rainy season and becoming hard in winter, and that it is expensive. It will be done.

For this reason, in recent years there has been active development of polyolefin-based fiber packaging films that are relatively inexpensive and are hardly affected by seasonal influences.

For example, packaging films that are flexible, transparent, and glossy have been developed by processing linear low-density polyethylene (LLDPE) into a water-cooled blown film or T-die casting film. However, although the Ll and DPE films produced by this processing method have good flexibility, they still have the drawback of being inferior in transparency and gloss compared to vinylon films.

In addition, as a propylene-based copolymer, it is obtained by polymerization (slurry polymerization) in an inert medium, and contains 6 wt% of ethylene.
It is known that the propylene random copolymer copolymerized above can be used to produce packaging films that are flexible, transparent, and glossy by the above processing method. However, since a large amount of active components dissolved in the inert solvent are removed, the product yield is not only poor, but also the polymerization is very slow. Next, JP-A-58-
79984, JP-A-54-85293, etc., disclose a copolymer in which propylene and butene-1 are copolymerized in a solution state (dissolution conditions). Although a packaging film that is flexible, has excellent transparency and gloss can be obtained, it has the disadvantage of extremely poor blocking resistance. This is thought to be due to the extremely small amount of boiling n-hebutane insoluble portion. Moreover, this copolymer is extremely resistant to one-time polymerization, which is carried out by solution polymerization.

In view of the above circumstances, the present inventors have developed a packaging film that is flexible, has excellent transparency and gloss, and has excellent anti-blocking properties, using a raw material resin that has a high product yield and is produced at low cost. As a result of intensive consideration to develop the
The raw material copolymer contains a specific comonomer as a component,
Moreover, it contains a limited amount and also contains a specific cold xylene soluble part (CX
S) and further has a specific boiling n-hebutane insoluble fraction (f
sfiIP), preferably obtained by a specific polymerization method, and more preferably obtained by polymerization with a specific catalyst system, and have completed the present invention.

That is, the present invention relates to a packaging film made of a random copolymer of propylene and an α-olefin having 4 or more carbon atoms, which satisfies the following conditions (1) to (2).

■ The content of α-olefin having 4 or more carbon atoms in the copolymer is 10 to 25 mol%. ■ The cold xylene soluble part of the copolymer is 13 to 60 wt%. ■ The boiling n-hebutane insoluble part of the copolymer is 7 wt%. % or more The first feature of the present invention is that a flexible film with excellent transparency and gloss can be obtained at low cost.

The second feature is that it has excellent blocking resistance.

The present invention will be explained in detail below.

The copolymer used in the present invention is preferably produced by a so-called gas phase polymerization method. This is because the slurry polymerization method, which is commonly used in which polymerization is carried out in an inert hydrocarbon,
Since a large amount of polymer dissolves in the inert hydrocarbon solvent,
Polymerization becomes extremely difficult, and not only is it difficult to obtain a soft polymer that meets the purpose of the present invention, but also the polymer yield is significantly reduced, which is extremely disadvantageous economically.

Polymerization can be carried out using a known fluidized bed reactor, stirred reactor, fluidized bed reactor equipped with a stirrer, or the like.

In addition, polymerization is possible without the gas liquefying in the reactor.
It is essential that the polymerization be carried out under conditions of temperature and pressure that do not cause the polymer particles to melt and become agglomerated. Particularly preferable polymerization conditions include a temperature range of 40 to 100°C and a temperature range of 1 to 50K.
The pressure range is g/crl (gauge pressure or less, abbreviated as G). In addition, for the purpose of adjusting the melt fluidity of the obtained polymer,
Preferably, a molecular weight regulator such as hydrogen is added. Polymerization can be carried out by batch polymerization, continuous polymerization, or a combination of the two, and monomers and molecular weight regulators consumed in polymerization can be reacted continuously or intermittently. can be supplied to the container. The copolymer used in the present invention can also be washed with alcohols or hydrocarbon solvents after gas phase polymerization for the purpose of removing catalyst residues or low molecular weight polymers.

The catalyst system used in the present invention is a so-called Ziegler-Natsuta catalyst, that is, a catalyst consisting of a compound of a transition metal of Groups I to II of the Periodic Table and an organic compound of a typical metal of Groups I to III of the Periodic Table. It is preferable that the metal compound or the catalyst component containing the metal compound is solid. Preferably, the transition metal compound is a compound containing at least titanium and a halogen, among which compounds with the general formula Ti(O
R) nX1n-n (R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, IQ is 2 to 4, n is 0
The titanium halogen compounds represented by the following formula (representing the number from rn-1) are preferred.

A specific example of such a compound is TiCzt.

TiCts, '1'1Ct2. 'I'1 (OCs
Hs)Czs, Ti(OCgI:l5)Cza, 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, TiCl3 is one of the most preferred transition metal compounds in the present invention, but α,
It is known to take β, γ and δ crystal forms,
In order to stereoregularly polymerize α-olefins having 8 or more carbon atoms, α, γ and δ types of Ti having layered crystallinity are used.
C7s is preferred. Tiola is generally obtained as a Tiola composition by reducing TiCl4 with hydrogen, metallic aluminum, metallic titanium, organoaluminum compounds, organomagnesium compounds, and the like.

Favorable Tic! The zs composition is made by reducing TiC1+ with metal aluminum and further activating TiCza AA and Ticz+ by mechanical crushing or the like.
is 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.

In addition, an alkoxy group-containing octavalent titanium halo obtained by reducing Ti(OR)4 (IL represents a hydrocarbon group having 1 to 20 carbon atoms) with an organoaluminum compound and then treating it with an ether compound and T i C1< Genides can also be suitably used.

TiC7J M acid or alkoxy group-containing trivalent titanium halide is the presence of hydrogen in liquefied propylene -IE
Particularly preferred is a composition that can be polymerized in combination with ethyl aluminum chloride for 4 hours at 65"C to produce polypropylene of 6,00 O1 or more per 19 hours. Such a TioB composition is disclosed in JP-A-47-34478.
Publication No. 55-27085, Patent Application No. 1987-
It can be manufactured by the method disclosed in Japanese Patent Application No. 26508, Japanese Patent Application No. 188471/1980, and the like. In addition, alkoxy group-containing octavalent titanium halide is available in a patent application filed in 1983.
It can be manufactured by the method disclosed in Japanese Patent No. 221659 and the like.

When a transition metal compound is used as a catalyst component supported on a suitable carrier, various solid polymers, especially α
- Polymers of olefins, various solid organic compounds, especially solid hydrocarbons, various solid inorganic compounds, especially 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. Commercially available magnesium compounds can be used as they are, but 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 preferable 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. A 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 Japanese Patent Application Laid-Open No. 56-8040.
It can be manufactured by the method disclosed in Japanese Patent Application Laid-Open No. 57-59915 and the like.

For stereoregular polymerization of α-olefins 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 of Groups 1 to 2 of the Periodic Table are organic compounds of aluminum, particularly those of the general formula R
An organoaluminum compound represented by eAtX8-0 (R represents a hydrocarbon group having 1 to 20 carbon atoms, hydrogen or halogen, and e is a number from 1 to 8) is preferred.

Specific examples of such compounds include triethylaluminum, triisobutylaluminum, diethylaluminum hydride, diethylaluminum chloride, diethylaluminum bromide, ethylaluminum sesquichloride, and ethylaluminum dichloride.

The most preferred compounds are triethylaluminum, diethylaluminium chloride and mixtures thereof.

The catalyst used in the present invention consists of the transition metal compound and the organometallic compound, but an electron-donating compound can be further used in combination to improve activity and/or stereoregularity.

Such electron-donating compounds include ethyl acetate, ε-caprolactone, methyl methacrylate, ethyl benzoate,
Ethyl P-anisate, methyl P-)ruylate, esters or acid anhydrides such as phthalic anhydride, ether compounds such as di-n-butyl ether, diphenyl ether, digram, tri-n-butyl phosphite, triphenyl phosphite, Examples include organic phosphorus compounds such as hexamethylene phosphoric triamide.

In addition, organic silicon compounds such as ketones, amines, amides, thioethers, alkoxysilanes having a 5i-Q-C bond, and aryloxysilanes can also be used.

In addition, 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 and an electron-donating compound before gas phase polymerization. .

The propylene copolymer used in the present invention (α-olefin having 4 or more carbon atoms is used alone or in combination as a comonomer).

As the α-olefin having 4 or more carbon atoms, butene-11
pentene-11 to pentene-1,4-, methylpentene-
However, butene-1 is the most preferred because it is difficult to liquefy and can maintain a high partial pressure during gas phase polymerization.If ethylene is included in the 0° comonomer component, it may cause poor transparency. Also, the same order occurs, such as deterioration of the transparency of the film over time, which is thought to be due to the bleed number of the acoustic component. The α-olefin content fi is preferably 12 to 24 mol%.If the α-olefin content with 4 or more carbon atoms is below the lower limit, the copolymer will have a softer If the upper limit is exceeded, the properties during gas phase polymerization will deteriorate, making stable production difficult.

The cold xylene soluble part (exs
) 4-t 18-60 wt% teari, 15-50
wt% is more preferred. When Cx8 falls below the lower limit,
This is undesirable since the copolymer may not achieve softness, resulting in a disadvantage in terms of polymer yield.

If CX8 exceeds the upper limit, the properties during gas phase polymerization will deteriorate and polymerization will become substantially impossible, and the film's resistance to scratching will deteriorate, which is not preferable.

The boiling n-hebutane insoluble part of the copolymer used in the present invention (
Bfl, IP) is 7 wt% or more, more preferably 19 wt% or more. If the BflIP force 5 is less than the lower limit, the resulting film will have poor blocking, which is not preferable.

When the copolymer used in the present invention is obtained by gas phase polymerization, no post-treatment such as a washing step is performed (or a moderate washing step may be performed; in any case, the copolymer at the time of use) As long as it falls within the above specified range.

The copolymer used in the present invention can be blended with a rubbery ethylene-α olefin random copolymer up to about 20 wt%, and can also be blended with other polymeric substances for hedges. Additionally, additives such as antistatic agents, antiblocking agents, stabilizers, and slip agents can be added.

In the present invention, known processing methods such as the T-die casting method and the water-cooling inflation method can be employed as a method for forming the copolymer into a film.

The physical properties of the film thus obtained include MD
The Young's modulus in the TD direction is preferably 8,000 Kg2 or less.

Once around the upper limit, vinylon film M(7)L.

It loses suppleness, which is undesirable.

The propylene-based co-IE composite packaging film produced as described above has flexibility, transparency, and gloss similar to vinylon film, and has excellent blocking resistance. It has extremely great practical value as there is almost no change in physical properties due to oxidation, and it can be manufactured at a low cost.

In addition, the data and evaluation in Examples and Comparative Examples were performed according to the following method.

(1) The α-olefin content in the copolymer was determined from the material balance. Furthermore, the content of butene-1 was further determined by a conventional method from the characteristic absorption of 'I'10 cm using an infrared spectrophotometer, and the results of mass balance were confirmed. In addition, in the measurement using an infrared spectrophotometer needle, a calibration curve was prepared and quantified using the quantitative values of C- and NMR for the propylene-butene-1 copolymer.

(2) The ethylene content in the copolymer was determined from the material balance. Furthermore, using an infrared spectrophotometer, 78
2 cm-'', 720'' characteristic absorption was determined using a conventional method to confirm the mass balance results. In addition, in the measurement using an infrared spectrophotometer, a calibration curve was prepared and quantified using quantitative values obtained by radiation measurement of 14C-labeled ethylene copolymer.

(3) Cold xylene soluble portion (OX8) Polymer 5y is bath dissolved in xylene 500- and then slowly cooled to room temperature. Then, the mixture is left in a bath at 20° C. for 4 hours, filtered, and the filtrate is concentrated, dried, and weighed.

(4) Extraction is carried out in a boiling an-heptane insoluble part (nHIP) Soxhlet extractor for 14 hours. Note that the reflux frequency is once every 5 minutes. How to read BflIP,
The extraction residue was dried and weighed.

(5) Intrinsic viscosity ([η]) Tetralin was adjusted to a concentration of 0.4 and 0.4 at 185°C using a conventional method.
2, 0.188 o, J: Hi 0.1 f/dt and 4 different points.

(6) Create a press sheet of ga ze copolymer with a thickness of 100μ, and
It was expressed as the difference between the haze after annealing treatment at °C for 9 hours and the haze before treatment.

(7) Young's modulus of film Conforms to ASTM-D882.

However, test piece shape: Distance between rectangular chucks of 20×120 = 50 ■ Tensile speed: 5 mm/min (8) Haze value (Maze) Compliant with A8'1i-D1008.

(9) Gross Compliant with ASTM-D52B.

(10) Plotski, superimpose two films, surface @ LOOc4 per 7
Conditioning was carried out at 23° C. for 24 hours with the Ky load applied. Thereafter, the two films are peeled off at a load increase rate of 1° f/min in a direction perpendicular to the film surface, and the maximum load CI) at that time is calculated and expressed as per film area io oi.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the examples unless it goes beyond the gist thereof.

Example 1 (IJ Preparation of solid catalyst containing titanium trichloride After purging a flask with a capacity of iz equipped with a stirrer and a dropping funnel with argon, 60 tons of titanium tetrachloride and 228 tons of 11-heptane were added.
- 1 ethylaluminum sesquichloride in a solution consisting of
86.A solution consisting of 800 g of 6- and n-hebutane is
Drop for 2 hours at 5 to -10°C. After stirring in the dark for 30 minutes at room temperature, the temperature was raised to 80°C.
It was heat-treated for 1 hour. Then, it was left to stand at room temperature, solid-liquid separation was carried out, and then 41! Repeat the washing process.

Next, 580 yd of 11-hebutane and 5 yd of diethylaluminium chloride were charged into the flask, and the temperature was maintained at 50°C. While stirring, propylene 32' was gradually fed into the solicited solution at 50'C for 2 hours to carry out a preliminary polymerization treatment. After the treatment, solid-liquid separation was performed, and washing was repeated twice with 400% n-hebutane.

Next, put 392 grams of toluene into the flask and lower the temperature to 8.
It was kept at 5'C. While stirring, II-butyl ether 1171) I and trilooctylamine 3.7-
was added and reacted at 85'C for 15 minutes. After reaction, iodine 1
A solution of 5.5F dissolved in 196+nl of toluene was added, and the reaction was further carried out at 85°C for 45 minutes.

After the reaction, solid-liquid separation was performed, and 500 m7 of toluene was added! once, I
After repeating washing three times with I-hebutane 500+d, drying was carried out under reduced pressure to obtain titanium trichloride-containing solid catalyst 901i'. The titanium trichloride-containing solid catalyst contained 65.2% by weight of titanium trichloride.

(2) Copolymerization of propylene and butene-1 was carried out using a fluidized bed reactor equipped with a stirrer and having an internal volume of 1 d. First, 60% of propylene-butene-1 copolymer particles for catalyst dispersion were added to the reactor.
The reactor was then flushed with phosphorus and then with propylene. .

Boost the pressure to 5 Kq/cJG with 4 mipropylene and 8
The circulating waste is supplied from the bottom of the reactor at a flow rate of 0 m/hr,
The polymer particles were kept in a fluidized state and then the following catalysts were fed to the reactor. For catalyst components (b) and (C), solutions diluted with hebutane were used.

(a) Solid catalyst containing titanium trichloride 21y (b) Diethylaluminum chloride 112y (C] Triethylaluminum 1lf (d) Methyl methacrylate 81, followed by hydrogen concentration 1.7 vol%, butene-12
Hydrogen, propylene, butene to make Q vo1%
1 is supplied, the pressure is increased to 10~~G, and the temperature of the fluidized bed is set 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 75Kf, 60V4 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 mixed with 210f of propylene oxide and 11f of methanol.
00g was added and treated at 80°C for 30 minutes. It was then dried to obtain a white powdery polymer. The same polymerization was repeated eight times, and the physical properties of the finally obtained polymer were measured.

The results are shown in Table 1.

(3) Film molding A film was obtained from the copolymer obtained in (2) under the following molding conditions.

Extruder: Egan 65mΩ extruder Screw: Single full flight type, L/D=24, C
, l'L, = 4.0 Temperature conditions: Die temperature 270℃ Die: Coat hanger die, lip opening 0.9
wa, rl] 500+m Chill roll temperature: 30℃ Film thickness = 40μ Young's modulus of this film is MD: 2150h/ca
, TD: 2180 Kr/c++! and
The haze was 1.1%, the gloss was 142%, and the film was flexible, transparent, and had high gloss, and was good.

Example 2 A copolymer was obtained under the same polymerization conditions as in Example 1, except that the catalyst system used in Example 1 and the amount of butene-1 charged were changed. The basic specifications of the obtained copolymer are shown in Table 1. Further, a film was obtained from this copolymer under the same conditions as those shown in Example-1. The Young's modulus of this film is MD: 2650 K9/di.

TD: 2690 Kg/i, haze is 1.
2%, the gloss was 141%, and the film was good like Example-1.

Comparative Example-1 This copolymer! It is obtained by a slurry polymerization method using l-hebutane as a solvent, and the active components that dissolve in n-hebutane have been removed. The basic specifications of this copolymer are shown in Table 1. A film was obtained from this copolymer under the same conditions as those shown in Example-1.

The Young's modulus of this film is MD: 4580 Kf/ca
, TD: 4640 Kg/cnl, haze was 1.8%, and gloss was 140%.

This film did not meet the purpose of the present invention from the viewpoint of flexibility.

Comparative Example-2 A copolymer was obtained under the same polymerization conditions as in Example-1, except that the catalyst system used in Example-1 and the use of ethylene instead of butene-1 were changed. The basic specifications of the obtained copolymer are shown in Table 1. Examples of this copolymer
A film was obtained under the same conditions as those shown in 1. Regarding this film, after several days had elapsed after the film was formed, what appeared to be an active component bleed onto the surface of the film, resulting in poor transparency, making the film difficult to put to practical use.

Comparative Example-3 A copolymer was obtained under the same polymerization conditions as in Example-1, except that the catalyst system used in Example-1, the amount of butene-1 charged, and the addition of ethylene were changed. The basic specifications of the obtained copolymer are shown in Table 1. Further, a film was obtained using this copolymer under the same conditions as those shown in Example-1. Regarding this film, as in Comparative Example 2, after several days had passed after the film was formed, what appeared to be atactic components bled onto the film surface, resulting in poor transparency, making the film difficult to put to practical use. Ah tko.

Claims (4)

[Claims] (1) A packaging film made of a random copolymer of propylene and an α-olefin having 4 or more carbon atoms, which satisfies the following conditions (1) to (2). ■ The content of the a-olefin having 4 or more carbon atoms in the copolymer is 10 to 25 mol%. ■ The cold xylene soluble part of the copolymer is 18 to 60 wt%. ■ The boiling n-hebutane insoluble part of the copolymer is 7 wt%. %that's all (2) The packaging film according to claim 1, wherein the copolymer is obtained by polymerizing in a gas phase substantially in the absence of a liquid medium. (3) The packaging film according to claim 1 or 2, wherein the α-olefin having 4 or more carbon atoms is butene-1. (4) Young's modulus in MD and TD direction is a, o o o
v- Claims 1, 2, or 8 which are:
Packaging film as described in section.