JP3210039B2 - Propylene copolymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a propylene random copolymer composition. More specifically, the present invention relates to a propylene random copolymer composition suitable for a heat seal film of a packaging film such as tobacco and caramel, obtained by blending two kinds of propylene-based random copolymers having specific properties in an appropriate ratio. The composition to be prepared.

[0002]

2. Description of the Related Art Propylene homopolymers or copolymers (hereinafter sometimes collectively referred to as propylene polymers) are being developed for use in a wide range of fields because of their excellent properties. Is well known. For example, polypropylene is widely used as a packaging film, but since polypropylene has a relatively high melting point, propylene is generally used to improve heat sealability at low temperatures in this type of application. A propylene random copolymer obtained by copolymerizing an α-olefin is used.

[0003] Such a conventional packaging film made of a propylene random copolymer is excellent in transparency and scratch resistance as compared with a film made of low-density polyethylene, but still has a heat sealing property at a low temperature. Is not enough. For the purpose of improving this, a copolymer in which the copolymerization amount of ethylene or an α-olefin having 4 to 20 carbon atoms is increased is known. Since stickiness (blocking resistance) is deteriorated and the rigidity of the film is lowered, further improvement is required. In order to improve the heat sealability and the blocking resistance at low temperatures as described above, it is desired to develop a propylene random copolymer having a low melting point and a small amount of components that cause stickiness.

[0004] Conventionally, an olefin polymerization catalyst comprising a titanium compound and an organoaluminum compound has been generally used for the production of a propylene polymer. In recent years, however, a new Ziegler-type olefin catalyst comprising a metallocene compound and an alumoxane (Japanese Patent Laid-Open 1958-1930
No. 9, No. 60-3500, No. 61-130314,
JP-A-63-295607, JP-A-1-275609,
JP-A-1-301704 and JP-A-2-41303), a propylene random copolymer using these olefin polymerization catalysts, and a method for producing the same (JP-A-62-1).
19215, JP-A-1-266116 and 2-17
No. 3014, No. 2-173015, No. 2-24720
No. 7, No. 7, and the use of the obtained copolymer as a heat sealant (Japanese Patent Application Laid-Open No. 2-173016) has been proposed. According to these proposals, a propylene random copolymer having a low melting point and a small amount of components causing stickiness has been obtained, but on the other hand, since the molecular weight distribution is narrow, film formation cannot be performed practically or However, there is a problem that it cannot be used because it causes surface roughness.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems.

[0006]

SUMMARY OF THE INVENTION Summary of the Invention <Summary> The present invention, 30 to the propylene random copolymer (A) below the 1-70% by weight, and a propylene random copolymer (B) It is a copolymer composition containing 99% by weight. Propylene random copolymer (A) : A propylene random copolymer comprising propylene, ethylene and / or an α-olefin having 4 to 20 carbon atoms and having the following characteristics (a) to (c). (A) 90 to 99.5 mol% of a structural unit obtained from propylene, ethylene and / or
Or 0.5 to 10 mol% of structural units obtained from an α-olefin having 4 to 20 carbon atoms; (b) a molecular weight distribution (Mw / Mn) of 3 or less; (c)
The average dissolution temperature (T ₅₀ ) is in the range of 40 to 90 ° C., and the dispersibility σ value is 10 or less. Propylene random copolymer (B) : a propylene random copolymer composed of propylene, ethylene and / or an α-olefin having 4 to 20 carbon atoms and having the following characteristics (d) to (e). (D) 90 to 99.5 mol% of a structural unit obtained from propylene, ethylene and / or
Alternatively, 0.5 to 10 mol% of structural units obtained from an α-olefin having 4 to 20 carbon atoms are present, and (e) the molecular weight distribution (Mw / Mn) is in the range of 3.5 to 10.

The molecular weight distribution (Mw / M
n) is gel permeation chromatography (G
PC) and the average elution temperature (T ₅₀ )
Is temperature rising elution fractionation using o-dichlorobenzene as a solvent (Temperature Rising Elution Fraction:
F ”) based on the elution curve of the polymer. Details of them will be described later.

<Effect> According to the present invention, it is possible to provide a film excellent in low-temperature heat sealability and blocking resistance.

[0009] DETAILED DESCRIPTION OF THE INVENTION <propylene random copolymer (A)> The propylene-based random copolymer (A) of the present invention, structural units derived from propylene 90 to 99.5 mol% of ethylene and And / or 0.5 to 10 mol% of structural units obtained from an α-olefin having 4 to 20 carbon atoms. Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene,
-Pentene, 3-methylbutene-1, 1-hexene, 4
-Methylpentene-1, 1-heptene, 1-octene,
Examples thereof include 1-nonene, 1-decene, and 1-hexadecene. Although the preferred proportion of the structural unit varies somewhat depending on the type of the monomer other than propylene, the proportion of the propylene structural unit is generally 92 to 99 mol%.

The molecular weight distribution (Mw / M) of the copolymer (A)
n) is in the range of 3 or less. It is preferably in the range of 1 to 2.8. In general, a polymer obtained with a catalyst comprising a metallocene compound and an alumoxane can obtain only those having Mw / Mn of 3 or less, but those having a Mw / Mn of more than 3 deteriorate the blocking resistance because the catalyst also has non-uniformity. Therefore, it is not preferable. The molecular weight of the copolymer of gel permeation chromatography (GPC) was measured according to "Gel Permeation Chromatography" published by Maruzen by Takeuchi. That is, using standard polystyrene having a known molecular weight (monodisperse polystyrene manufactured by Tosoh Corporation), it was converted into a number average molecular weight (Mn) and a weight average molecular weight (Mw) by a universal method, and the value of Mw / Mn was obtained. The measurement is 150C-ALC / GPC manufactured by Waters.
And three columns of AD80M / S manufactured by Showa Denko KK were used. The sample is 0.2-wt% in 0-dichlorobenzene
The reaction was carried out at 140 ° C. at a flow rate of 1 ml / min.

The average elution temperature (T ₅₀ ) by TREF is 4
It is in the range of 0 to 90 ° C, and the dissolution degree (σ value) is 10 or less. The average dissolution temperature (T ₅₀ ) indicates the temperature at which the cumulative weight of the dissolution polymer becomes 50% by weight. The elution dispersity (σ value) is calculated by assuming that the elution amount by TREF follows a normal probability distribution with respect to the elution temperature.
(T) is the following formula:

[0012]

(Equation 1)

Is the σ value defined as expressed by
Specifically defined _{σ = T 84. 1 -T 50} . T _{84. 1} shows the temperature at which the cumulative weight becomes 84.1 wt%. still,
Measurement of TREF is based on the Journal of Applied Polymer S
cience 26, 4217-4231 (1981). The average dissolution temperature and dissolution degree of dispersion are preferably 50 to 85 ° C. and the σ value is 9 or less. More preferably, it is 60 to 80 ° C. and the σ value is 6 or less. Those having an average elution temperature of less than 40 ° C have too low a molecular weight or cause a blocking because the melting point is too low. Does not have heat sealability. If the dissolution degree is 10 or more, the components causing blocking increase, so that both of the heat sealing property at low temperature and the blocking resistance cannot be satisfied.

The propylene random copolymer (A) is
It can be produced using a polymerization catalyst comprising the following components (C) and (D). <Component (C)> component C is represented by the following formula: is _{Q (C 5 H 4-a} R 1 a) (C 5 H 4-b R 2 b) a transition metal compound represented by Mexy. Where Q is
A binding group that bridges two conjugated five-membered ring ligands. Specifically, (a) an alkylene group such as a methylene group, an ethylene group, an isopropylene group, a phenylmethylmethylene group, a diphenylmethylene group, and a cyclohexylene group; (b) a silylene group, a dimethylsilylene group, a phenylmethylsilylene group, and a diphenylsilylene group , Disilylene group,
(C) a hydrocarbon group containing germanium, phosphorus, nitrogen, boron or aluminum [specifically, (CH ₃ ) ₂ Ge
Group, (C ₆ H ₅ ) ₂ Ge group, (CH ₃ ) P group, (C ₆ H ₅ ) P
Group, (C ₄ H ₉ ) N group, (C ₆ H ₅ ) N group, (CH ₃ ) B
Group, (C ₄ H ₉ ) B group, (C ₆ H ₅ ) B group, (C ₆ H ₅ ) Al
Group, (CH ₃ O) Al group, etc.]. Preferred are an alkylene group and a silylene group.

[0015] _{(C 5 H 4-a R} 1 a) and _{(C 5 H 4-b R} 2 b)
Although the conjugated five-membered ring ligand represented by is defined separately, a and b, and R ¹ and R ²
Is the same (details will be described later), it is needless to say that the two conjugated five-membered ring groups may be the same or different. One specific example of this conjugated five-membered ring group is a =
0 (or b = 0) is a cyclopentadienyl group (no substituent other than the crosslinking group Q). When the conjugated five-membered ring group has a ≠ 0 (or b ≠ 0) and has a substituent, one specific example of R ¹ (or R ² ) is a hydrocarbon group (C _{1 to} C ₂₀ and preferably C ₁ -C ₁₂ ). This hydrocarbon group is bonded as a monovalent group to a cyclopentadienyl group, but is bonded as a divalent group to a cyclopentadienyl group. You may. A typical example of the latter is R
¹ (or R ² ) forms a fused 6-membered ring by sharing the double bond of the cyclopentadienyl group, that is, the conjugated 5-membered ring group is an indenyl group or a fluorenyl group . That is, typical examples of the conjugated five-membered ring group are a substituted or unsubstituted cyclopentadienyl group, an indenyl group and a fluorenyl group.

R ¹ and R ² each represent the above-mentioned C _1-
In addition to C ₂₀ , preferably C ₁ -C ₁₂ hydrocarbon groups, halogen groups (eg, fluorine, chlorine, bromine), alkoxy groups (eg, C ₁ -C ₁₂ ), silicon-containing hydrocarbon groups ( for example, a silicon atom ^{-Si (R 1) (R 2} )
(A group having about 1 to 24 carbon atoms contained in the form of (R ³ )), a phosphorus-containing hydrocarbon group (for example, adding a phosphorus atom to -P (R) (R)
), A nitrogen-containing hydrocarbon group (for example, a group having about 1 to 18 carbon atoms containing a nitrogen atom in the form of -N (R) (R ')) or a boron-containing hydrocarbon group. A hydrocarbon group (for example, a group having about 1 to 18 carbon atoms containing a boron atom in the form of -B (R) (R)). When a (or b) is 2 or more and a plurality of R ¹ (or R ² ) are present, they may be the same or different. a
And b are integers satisfying 0 ≦ a ≦ 4 and 0 ≦ b ≦ 4.

Me is a transition metal from Groups IVB to VIB of the Periodic Table, preferably titanium, zirconium, and hafnium. X and Y each represent hydrogen, a halogen group, a carbon number of 1 to
20, preferably 1 to 10 hydrocarbon groups, 1 to 1 carbon atoms
20, preferably 1 to 10 alkoxy groups, amino groups,
A phosphorus-containing hydrocarbon group having 1 to 20, preferably 1 to 12 carbon atoms (specifically, for example, a diphenylphosphine group) or a silicon-containing hydrocarbon group having 1 to 20, preferably 1 to 12 carbon atoms (specifically, Represents, for example, a trimethylsilyl group). X and Y may be the same or different. Of these, a halogen group and a hydrocarbon group are preferred.

Specific examples of the transition metal compound when Me is zirconium are as follows. (A) Transition metal compounds having a five-membered ring ligand bridged by an alkylene group, such as (1) methylenebis (indenyl) zirconium dichloride, (2) ethylenebis (indenyl) zirconium dichloride, (3) ethylenebis (indenyl) Zirconium monohydride monochloride, (4) ethylenebis (indenyl) methyl zirconium monochloride,
(5) ethylenebis (indenyl) zirconium monomethoxymonochloride,

(6) Ethylene bis (indenyl) zirconium diethoxide, (7) ethylene bis (indenyl) zirconium dimethyl, (8) ethylene bis (4
5,6,7-tetrahydroindenyl) zirconium dichloride, (9) ethylenebis (2-methylindenyl) zirconium dichloride, (10) ethylene (2,4
-Dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride;

(11) Ethylene (2-methyl-4-tertbutylcyclopentadienyl) (3'-tertbutyl-5 '
-Methylcyclopentadienyl) zirconium dichloride, (12) ethylene (2,3,5-trimethylcyclopentadienyl) (2 ', 4', 5'-trimethylcyclopentadienyl) zirconium dichloride, (13) isopropyl Ridenebis (indenyl) zirconium dichloride, (14) isopropylidenebis (2,4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride, (15) isopropylidenebis (2- Methyl-4-tertbutylcyclopentadienyl) (3′-tertbutyl-5-methylcyclopentadienyl) zirconium dichloride,

(16) Methylene (cyclopentadienyl)
(3,4-dimethylcyclopentadienyl) zirconium dichloride, (17) methylene (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) zirconium chloride hydride, (18) methylene (cyclopentadienyl) ( 3,4-dimethylcyclopentadienyl) zirconium dimethyl, (19) methylene (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) zirconium diphenyl, (20) methylene (cyclopentadienyl) (trimethylcyclo Pentadienyl)
Zirconium dichloride,

(21) Methylene (cyclopentadienyl)
(Tetramethylcyclopentadienyl) zirconium dichloride, (22) isopropylidene (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) zirconium dichloride, (23) isopropylidene (cyclopentadienyl) (2, 3,4,5-tetramethylcyclopentadienyl) zirconium dichloride, (24) isopropylidene (cyclopentadienyl) (3-methylindenyl) zirconium dichloride, (25) isopropylidene (cyclopentadienyl) (fluorenyl ) Zirconium dichloride,

(26) isopropylidene (2-methylcyclopentadienyl) (fluorenyl) zirconium dichloride, (27) isopropylidene (2,5-dimethylcyclopentadienyl) (3,4-dimethylcyclopentadienyl) Zirconium dichloride, (28) isopropylidene (2,5-dimethylcyclopentadienyl) (fluorenyl) zirconium dichloride, (29) ethylene (cyclopentadienyl) (3,5-dimethylcyclopentadienyl) zirconium dichloride, 30) ethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride,

(31) ethylene (2,5-dimethylcyclopentadienyl) (fluorenyl) zirconium dichloride, (32) ethylene (2,5-diethylcyclopentadienyl) (fluorenyl) zirconium dichloride,
(33) Diphenylmethylene (cyclopentadienyl)
(3,4-diethylcyclopentadienyl) zirconium dichloride, (34) diphenylmethylene (cyclopentadienyl) 3,4-diethylcyclopentadienyl)
Zirconium dichloride, (35) cyclohexylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, (36) cyclohexylidene (2,5-dimethylcyclopentadienyl) (3 ′, 4′-dimethyldimethylcyclopentadiene) Enyl) zirconium dichloride and the like.

(B) Transition metal compounds having a five-membered ring ligand of a silylene group, such as (1) dimethylsilylenebis (indenyl) zirconium dichloride, (2) dimethylsilylene (4,5,6
7-tetrahydroindenyl) zirconium dichloride, (3) dimethylsilylene (2,4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride, (4) phenylmethylsilylenebis (indenyl) ) Zirconium dichloride, (5) phenylmethylsilylenebis (4, 5, 6,
7-tetrahydroindenyl) zirconium dichloride,

(6) Phenylmethylsilylene (2,4-
Dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride,
(7) phenylmethylsilylene (2,3,5-trimethylcyclopentadienyl) (2,4,5-trimethylcyclopentadienyl) zirconium dichloride, (8)
Phenylmethylsilylenebis (tetramethylcyclopentadienyl) zirconium dichloride, (9) diphenylsilylenebis (indenyl) zirconium dichloride, (10) tetramethyldisilylenebis (indenyl)
Zirconium dichloride,

(11) tetramethyldisilylenebis (cyclopentadienyl) zirconium dichloride, (12) tetramethyldisilylene (3-methylcyclopentadienyl) (indenyl) zirconium dichloride, (13) dimethylsilylene (cyclopentane Dienyl) (3,4-dimethylcyclopentadienyl) zirconium dichloride, (14) dimethylsilylene (cyclopentadienyl)
(Trimethylcyclopentadienyl) zirconium dichloride, (15) dimethylsilylene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride,

(16) dimethylsilylene (cyclopentadienyl) (3,4-diethylcyclopentadienyl) zirconium dichloride, (17) dimethylsilylene (cyclopentadienyl) (triethylcyclopentadienyl) zirconium dichloride, 18) dimethylsilylene (cyclopentadienyl) (tetraethylcyclopentadienyl) zirconium dichloride, (19) dimethylsilylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, (20) dimethylsilylene (cyclopentadienyl) (2) , 7-Di-t-butyl fluorenyl) zirconium dichloride,

(21) dimethylsilylene (cyclopentadienyl) (octahydrofluorenyl) zirconium dichloride, (22) dimethylsilylene (2-methylcyclopentadienyl-fluorenyl) zirconium dichloride, (23) dimethylsilylene (2 , 5-dimethylcyclopentadienyl) (fluorenyl) zirconium dichloride, (24) dimethylsilylene (2-ethylcyclopentadienyl) (fluorenyl) zirconium dichloride, (25) dimethylsilylene (2,5-diethylcyclopentadienyl) ) (Fluorenyl) zirconium dichloride,

(26) diethylsilylene (2-methylcyclopentadienyl) (2,7-di-t-butylfluorenyl) zirconium dichloride, (27) dimethylsilylene (2,5-dimethylcyclopentadienyl) (2,7
-Di-t-butylfluorenyl) zirconium dichloride, (28) dimethylsilylene (2-ethylcyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, (29) dimethylsilylene ( Diethylcyclopentadienyl) (2,7-di-t-butylfluorenyl) zirconium dichloride, (30) dimethylsilylene (methylcyclopentadienyl) (octahydrofluorenyl) zirconium dichloride, (31) dimethylsilylene (Dimethylcyclopentadienyl) (octahydrofluorenyl) zirconium dichloride, (3
2) Dimethylsilylene (ethylcyclopentadienyl)
(Octahydrofluorenyl) zirconium dichloride, (33) dimethylsilylene (diethylcyclopentadienyl) (octahydrofluorenyl) zirconium dichloride and the like.

(C) Transition metal compounds having a five-membered ring ligand bridged by a hydrocarbon group containing germanium, aluminum, boron, phosphorus or nitrogen, such as (1) dimethylgermanium bis (indenyl) zirconium dichloride, 2) Dimethylgermanium (cyclopentadienyl) (fluorenyl) zirconium dichloride, (3) methylaluminum bis (indenyl)
Zirconium dichloride, (4) phenylaluminum bis (indenyl) zirconium dichloride, (5) phenylphosphinobis (indenyl) zirconium dichloride, (6) ethylholanobis (indenyl) zirconium dichloride, (7) phenylaminobis (indenyl) zirconium dichloride, (8) Phenylamino (cyclopentadienyl) (fluorenyl) zirconium dichloride and the like.

(D) Further, compounds obtained by replacing chlorine in the compounds (a) to (c) with bromine, iodine, hydride, methyl, phenyl and the like can also be used. Further, in the present invention, a compound in which the central metal of the zirconium compounds exemplified in the above (a) to (d) is changed from zirconium to titanium, hafnium, niobium, molybdenum or tungsten can be used as the component (C). Of these, preferred are zirconium compounds, hafnium compounds and titanium compounds. More preferred are zirconium compounds and hafnium compounds cross-linked with an alkylene group or a silylene group.

<Component D> Component (D) is alumoxane. Alumoxanes are products obtained by the reaction of one trialkylaluminum or two or more trialkylaluminums with water. Specifically, methylalumoxane, ethylalumoxane, butylalumoxane, isobutylalumoxane, etc. obtained from one type of trialkylaluminum, and methylethylalumoxane, methylbutylalumoxane obtained from two types of trialkylaluminum and water Xan, methyl isobutylalumoxane and the like are exemplified. These alumoxanes may be used in combination of two or more, and may be used in combination with other alkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum, and dimethylaluminum chloride. It is also possible to use a modified alumoxane by reacting two kinds of alumoxanes or one kind of alumoxane with another organoaluminum compound. Of these, preferred are methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, and a mixture of these alumoxane and trialkylaluminum. Particularly preferred are methylalumoxane and methylisobutylalumoxane.

These alumoxanes can be prepared under various known conditions. Specifically, the following method can be exemplified. (A) a method in which a trialkylaluminum is directly reacted with water using an appropriate organic solvent such as toluene, benzene or ether; (b) a salt hydrate having a trialkylaluminum and water of crystallization such as copper sulfate or aluminum sulfate (C) a method of reacting trialkylaluminum with water impregnated in silica gel or the like, (d) mixing trimethylaluminum and triisobutylaluminum, and adding an appropriate compound such as toluene, benzene, or ether. A method of directly reacting with water using an organic solvent,
(E) a method in which trimethylaluminum and triisobutylaluminum are mixed, and heated and reacted with a salt hydrate having water of crystallization, such as copper sulfate or aluminum sulfate hydrate;
(F) a method of impregnating silica gel or the like with water and treating with triisobutylaluminum, followed by additional treatment with trimethylaluminum; (g) synthesizing methylalumoxane and isobutylalumoxane by a known method; A method of mixing and quantitatively reacting by heating.

<Formation of Catalyst> The catalyst used in the present invention is prepared by subjecting the above-mentioned components (C) and (D) to a polymerization in a polymerization vessel or outside a polymerization vessel in the presence or absence of a monomer to be polymerized. It can be prepared by contact. The amounts of the components (C) and (D) used in the present invention are arbitrary, but generally, the atomic ratio (Al / Me) between the aluminum atom in the component (D) and the transition metal in the component (C).
0.01 to 100,000, preferably 0.1 to 30,0
00. The contacting method is optional and may be introduced separately during the polymerization and brought into contact, or may be brought into contact in advance.

The catalyst of the present invention comprises the components (C) and (D)
In addition to the above, it is possible to include other components as described above. However, as the third component (optional component) that can be added to the components (C) and (D), for example, water, methanol, Active hydrogen-containing compounds such as ethanol and butanol; electron-donating compounds such as ethers, esters and amines; phenyl borate, dimethylmethoxyaluminum,
Examples thereof include alkoxy-containing compounds such as phenyl phosphite, tetraethoxysilane, and diphenyldimethoxysilane; and organic boron compounds such as triphenylboron and tributylboron.

<Method for Producing Propylene-Based Random Copolymer (A)> Production of a propylene-based random copolymer (A) using a polymerization catalyst comprising components (C) and (D) is as follows.
It is carried out by mixing and contacting propylene with ethylene and / or an α-olefin having 4 to 20 carbon atoms. The amount ratio of each monomer in the reaction system does not need to be constant over time, and it is convenient to supply each monomer at a constant mixing ratio, and to change the mixing ratio of the supplied monomers over time. Is also possible. Further, any of the monomers can be added in portions in consideration of the copolymerization reaction ratio.

The polymerization mode can be any mode as long as the catalyst component and each monomer are in efficient contact. Specifically, a slurry method using an inert solvent, a slurry method using propylene and an α-olefin as a solvent without substantially using an inert solvent, a solution polymerization method, or a method in which each monomer is substantially used without using a substantially liquid solvent For example, a gas phase method or the like for keeping gas in a gaseous state can be adopted. Further, the present invention is also applicable to a method of performing continuous polymerization, batch polymerization or preliminary polymerization. In the case of slurry polymerization, a single or a mixture of saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, pentane, cyclohexane, benzene, and toluene is used as a polymerization solvent. The polymerization temperature is about -48 ° C, preferably 0 ° C to 15 ° C.
At 0 ° C., hydrogen can then be used additionally as a molecular weight regulator. In the case of slurry polymerization, the amount of the component (C) used is 0.0001 to 1.0 g.
Per liter solvent range is preferred. The polymerization pressure is 0 to 90
Kg / cm ² G, and preferably from 0~60Kg / cm ² G, particularly preferably 1~50Kg / cm ² G.

It is preferable to use a catalyst in which propylene is previously polymerized alone before copolymerization for the purpose of improving the activity, eliminating the solvent-soluble by-product polymer or preventing the melting point from lowering. At this time, the ratio of the propylene homopolymer portion to the total copolymer is usually 10% by weight or less, preferably 5% by weight or less, and the DSC peak based on the propylene homopolymer is recognized in the product polymer. It is preferable that it is not a degree. In this case, the polymerization temperature at the time of propylene homopolymerization is generally equal to or lower than the temperature of the subsequent copolymerization. Therefore, the temperature at the time of propylene homopolymerization is −30 to 70 ° C., preferably 0 to 50 ° C. The pressure can be usually from normal pressure to 20 kg / cm ² G, but is not necessarily limited to this as long as the ratio of the propylene homopolymerized portion to the target copolymer is within the above-mentioned predetermined range. The molecular weight of the copolymer can be controlled by adding hydrogen to the polymerization system.

<Propylene random copolymer (B)>
The propylene random copolymer (B) of the present invention has a structural unit obtained from propylene of 90 to 99.5 mol%,
0.5 to 10 mol% of structural units obtained from ethylene and / or an α-olefin having 4 to 20 carbon atoms. As an α-olefin having 4 to 20 carbon atoms, 1
-Butene, 1-pentene, 3-methylbutene-1,1-
Hexene, 4-methylpentene-1, 1-heptene, 1
-Octene, 1-nonene, 1-tesene, 1-hexadecene and the like are exemplified. Although the preferred proportion of the structural unit varies somewhat depending on the type of the monomer other than propylene, the proportion of the propylene structural unit is generally 92 to 99 mol%.

The ratio of Mw / Mn measured by gel permeation chromatography (GPC) is 3.5 to 10
, Preferably in the range of 4-9. Mw / Mn> 1
If it is 0, it is difficult to mix the copolymer (A) and the blend uniformly, and the transparency is deteriorated and the surface is roughened. on the other hand,
When Mw / Mn <3.5, the film formability of the whole polymer is deteriorated, and the effect of improving the formability of the composition of the present invention cannot be obtained.

<Production of propylene-based random copolymer (B)> The present polymer can be polymerized using a generally known Ziegler-type catalyst comprising a titanium compound and organoaluminum. Non-limiting examples include a catalyst consisting of a TiCl ₃ composition manufactured by Marubeni Solvay and diethylaluminum chloride, or a highly active catalyst component containing titanium, magnesium, and halogen, and triethylaluminum, and A catalyst comprising an electron donating compound to be used accordingly can be mentioned.

<Production of Copolymer Composition> The composition of the present invention can be obtained by blending a propylene random copolymer (A) and a copolymer (B). The mixing ratio of the copolymer (A) is 1 to 70% by weight, preferably 3 to 5%.
0% by weight, more preferably 5 to 40% by weight. 1
If the amount is less than 10% by weight, the effect of improving the low-temperature heat sealability and the blocking resistance cannot be obtained. If the amount is more than 70% by weight, the moldability cannot be improved and the film cannot be formed substantially. In the composition of the present invention, in addition to the above essential components, additional components can be further added as long as the effects of the present invention are not significantly impaired. These additional components include antioxidants, neutralizers, UV absorbers, antifoamers, dispersants, antistatic agents, lubricants, molecular weight regulators (peroxides), etc. used for ordinary polyolefins. And various auxiliaries such as a nucleating agent, a rubber component, and a coloring agent.

As the method for producing the composition of the present invention, generally used Henschel mixer, super mixer, V
Blender, tumbler mixer, ribbon blender,
It is preferable that the mixture is mixed for a predetermined time using a mixer or kneader such as a Banbury mixer, a kneader blender, or an extruder, and the mixture is formed into pellets using a normal extruder. This composition is processed into various molded articles through extrusion molding, hollow molding, film molding, injection molding, compression molding and the like. In particular, the effect of the present invention is greatly exerted on an extruded product.

[0045]

【Example】

Experimental Example Production of Propylene-based Random Copolymer (A) : [ Production of Catalyst Component (C)] Dimethylsilylbis (tetrahydroindenyl) zirconium dichloride was added to J. Orgm.
et. Chem. (342) 21-29 1988 and J. Orgmet. Chem. (369) 359
Synthesized according to 370370 1989 . Specifically, in a 300 ml flask purged with nitrogen, 5.4 g of bis (indenyl) dimethylsilane was diluted with 150 ml of tetrahydrofuran, cooled to 50 ° C. or lower, and then charged with 23.36 ml of n-butyllithium (1.6 M / L). 6 ml was added dropwise over 30 minutes. After completion of the dropwise addition, the temperature was raised to room temperature over 1 hour, and the reaction was carried out for 4 hours at the elevated temperature to synthesize a reaction solution A.

200 ml of tetrahydrofuran was introduced into a 500 ml flask purged with nitrogen, cooled to -50 ° C. or lower, and 4.38 g of zirconium tetrachloride was slowly introduced. Next, after introducing the entire amount of the reaction solution A, the temperature was slowly raised to room temperature over 3 hours. After reacting at room temperature for 2 hours, the temperature was further raised to 60 ° C. and reacted for 2 hours. After completion of the reaction, the solvent was distilled off under reduced pressure, and the residue was dissolved in 100 ml of toluene and distilled off again to obtain 3.86 g of dimethylsilylbis (indenyl) zirconium dichloride crude crystals. Then
The crude crystals were dissolved in 150 ml of dichloromethane, and 50
0 ml autoclave, platinum and carbon (0.
After introducing 5 g of a 5 wt% platinum-supported catalyst, a hydrogenation reaction was carried out at a temperature of 50 ° C. for 5 hours under a hydrogen pressure of 50 kg / cm ² G.
After completion of the reaction, the catalyst was filtered off, the solvent was distilled off under reduced pressure, extracted with toluene, and recrystallized to obtain 1.26 g of the target dimethylsilylbis (tetrahydroindenyl) zirconium dichloride.

[Production of catalyst component (D)] 100 ml of dehydrated and deoxygenated toluene was introduced into a 1000 ml flask equipped with a stirrer and a reflux condenser which were sufficiently purged with nitrogen. Next, 0.72 g (10 mmol) of trimethylaluminum and 1.96 g (10 mmol) of triisobutylaluminum were added to one of the two dropping funnels in 50 m of toluene.
Then, toluene containing saturated water was introduced into the other one, and a mixed aluminum solution and toluene containing saturated water were fed at equimolar amounts of Al and water over 3 hours at 30 ° C. After the feed was completed, the temperature was raised to 50 ° C. and the reaction was performed for 2 hours. After completion of the reaction, the solvent was distilled off under reduced pressure to obtain 1.9 g of a white solid.

[Production of copolymer (A) -1] 5 l of n-heptane sufficiently dehydrated and deoxygenated in a 15 l stainless steel autoclave equipped with a stirrer and a temperature controller were prepared. 4.6 mg of C) and 30 mm of methylisobutylalumoxane in terms of aluminum atom.
propylene was fed at a rate of 360 g / hour and ethylene at a rate of 7.4 g / hour for 4 hours at 40 ° C. under polymerization conditions. The internal pressure at the end of the feed was 3.5 kg / cm ² G. As a result of continuous polymerization for 3 hours after the end of the feed,
The pressure dropped to 1.7 kg / cm ² G. The residual gas was purged, butanol was added in an amount of 400 ml, the mixture was detouched at 50 ° C. for 1 hour, and then slowly fed to a steam stripping tank over 1 hour to evaporate the solvent. The polymer was separated and recovered, and dried. As a result, 1.10 kg of copolymer (A) -1 was obtained. The polymer contained 2.5% by weight of ethylene. As a result of GPC measurement, the number average molecular weight was 23,
000, Mw / Mn = 2.00. As a result of DSC measurement, the melting point was 128.6 ° C. As a result of TREF measurement, the average elution temperature was 74 ° C., and the elution dispersion degree was 3.5.

The average elution temperature (T ₅₀ ) of the copolymer by the TREF method was measured as follows. The sample was dissolved in o-dichlorobenzene to prepare a 0.4% by weight solution, and the solution corresponding to 2 mg of the sample was injected into a cross-separation apparatus (CFC-101-L, manufactured by Mitsubishi Yuka Co., Ltd.). After cooling from 140 ° C. to 0 ° C. at a rate of 1 minute, the sample was loaded on a TREF column. Then, 0,10,20,30,4
0,45,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,
The temperature was increased stepwise to 97, 100, 102, 105, 120 and 140 ° C, and the polymer eluted at each temperature was extracted from the column at a rate of 1.0 cm ³ / min, and each eluted fraction was automatically sent to a GPC column for separation and separation. The eluted polymer concentration was quantified at a wavelength of 3.42 μm. The peak data processing was performed using a program attached to the apparatus. Based on the curve thus obtained, the elution temperature at which the cumulative weight of the eluted polymer became 50% was expressed as an average elution temperature (T ₅₀ ).

[Production of copolymer (A) -2] The polymerization reaction was carried out under the same conditions as in the production of copolymer (A) -1 except that the feed rate of ethylene was changed to 15.0 g / hour. Was done. As a result, 1,150 grams of polymer (A) -2 was obtained. The ethylene content in the copolymer was 5.7% by weight, the number average molecular weight was 22,600, Mw / Mn was 2.15, and the melting point was 114 ° C. The average elution temperature by TREF was 58 ° C, and the elution dispersity was 8.8.

Production of propylene-based random copolymer (B)
Forming copolymer (B) as a -1, ethylene content 2.5 wt%
Was used. It has an MFR of 9.2 and a molecular weight distribution (Mw / Mn) of 6.5.
It was 0. The melting point was 147.7 ° C., the average elution temperature (T ₅₀ ) was 95 ° C., and the elution dispersity was 7.2. As the copolymer (B) -2, a propylene ethylene random copolymer having an ethylene content of 4.5% by weight [F manufactured by Mitsubishi Yuka Co., Ltd.]
X4 (trade name)] was used. The MFR was 6.2 and the molecular weight distribution (Mw / Mn) was 5.9. The melting point was 140 ° C., the average dissolution temperature (T ₅₀ ) was 87 ° C., and the dissolution degree was 10.5.

Example 1 As a substrate layer, MFR 2.3 g / 10 min and II9
100 parts of 8% polypropylene [FL6S (trade name) manufactured by Mitsubishi Yuka Co., Ltd.] was mixed with 0.6 parts by weight of glycerin monostearate and 0.1 part by weight of N, N'bis (2-hydroxyethyl) alkylamine. Was used. Also, 2,6-di-t-butyl-p as an antioxidant was added to 10 parts by weight of the copolymer (A) -1 and 90 parts by weight of the copolymer (B) -1 as a surface layer. -Cresol 0.10
Parts by weight, 0.05 parts by weight of calcium stearate as a hydrochloric acid catching agent, and 0.15 parts by weight of silica having an average particle diameter of 3 μm were added, and the mixture was pelletized.

Using these compositions, they were laminated under the following conditions and sequentially biaxially stretched to obtain a biaxially stretched polypropylene multilayer film. The polypropylene as the base material layer and the composition of the present invention as the surface layer are each formed into a three-layer structure of surface layer composition / polypropylene / surface layer composition using a three-layer die from a 115 mm diameter and 35 mm diameter extruder. In the same manner, a sheet was formed by co-extrusion at 250 ° C. Subsequently, the film was stretched 5 times in the radial direction at 115 ° C. using a difference in roll peripheral speed. Next, the film was stretched 10 times in the transverse direction in a tenter oven at 168 ° C., heat-set at 155 ° C., and subsequently subjected to a corona discharge treatment on one side of the film to obtain a biaxially stretched multilayer film. The thickness configuration was 1 μ / 23 μ / 1 μ.

The heat sealing temperature and the blocking resistance of this film were measured under the following conditions. Table 1 shows the results. Heat seal temperature : Using a heat seal bar of 5 mm x 200 mm, at each set temperature, a heat seal pressure of 1 kg /
A sample having a width of 20 mm was cut out from a sample sealed under heat sealing conditions of 0.5 cm ² and a heat sealing time of 0.5 second, and separated at a tensile speed of 500 mm / min using a Shopper type tester. The heat sealing temperature was used. Blocking resistance : Two films (corona discharge treated surfaces) are stacked so that the contact area is 10 cm ² , sandwiched between two glass plates, and applied with a load of 50 g / cm ² under an atmosphere of 40 ° C. , And the maximum load at the time of peeling was measured with a shopper type testing machine.

Examples 2-3 and Comparative Example 1 The procedure of Example 1 was repeated except that the mixing ratio of copolymer (A) -1 and copolymer (B) -1 was changed as shown in Table 1. Evaluation was performed in the same manner as in Example 1. Table 1 shows the results. In addition,
Since the film of Comparative Example 1 had severe surface roughness and was not practical, the measurement of the heat sealing temperature and the blocking resistance could not be performed.

Example 4 Evaluation was carried out in the same manner as in Example 1 except that copolymer (A) -1 in Example 1 was changed to Copolymer (A) -2. The results are shown in Table 1.

Comparative Example 2 The above copolymer (B) -2 was used as a surface layer in Example 1 for 10 times.
Evaluation was performed in the same manner as in Example 1 except that 0 parts by weight was used. Table 1 shows the results.

[0058]

[Table 1]

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Eiji Uchino 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Yuka Co., Ltd. In Yokkaichi Research Institute, Inc. (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 23 / 14-23/16

Claims (1)

(57) [Claims] 1. A copolymer composition comprising the following propylene random copolymer (A) in an amount of 1 to 70% by weight and the propylene random copolymer (B) in an amount of 30 to 99% by weight. Propylene random copolymer (A) : A propylene random copolymer comprising propylene, ethylene and / or an α-olefin having 4 to 20 carbon atoms and having the following characteristics (a) to (c). (A) When the structural unit obtained from propylene is 90 to 99.
5 to 10 mol% of structural units obtained from 5 mol%, ethylene and / or an α-olefin having 4 to 20 carbon atoms, and (b) a molecular weight distribution (Mw / Mn) of 3 or less. (C) The average dissolution temperature (T ₅₀ ) is in the range of 40 to 90 ° C., and the dispersibility σ value is 10 or less. Propylene random copolymer (B) : a propylene random copolymer composed of propylene, ethylene and / or an α-olefin having 4 to 20 carbon atoms and having the following characteristics (d) to (e). (D) When the structural unit obtained from propylene is 90 to 99.
5 to 10 mol% of structural units obtained from 5 mol%, ethylene and / or an α-olefin having 4 to 20 carbon atoms, (e) a molecular weight distribution (Mw / Mn) of 3.5 to 10 Range.