JPS61241340A - Ethylene-alpha-olefin copolymer composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating a crystalline ethylene-alpha-olefin copolymer with a low crystalline ethylene-alpha-olefin copolymer in a specific amount, having improved moldability, transparency, impact resis tance, etc., and suitable to films for packaging, etc. CONSTITUTION:An ethylene-alpha-olefin copolymer composition obtained by incorporating (A) 95-40pts.wt., preferably 90-60pts.wt. copolymer of ethylene and a 4-10C alpha-olefin, e.g. 1-butene, in a small proportion having 0.01-50g/10min melt flow rate, 0.91-0.94g/cm<3> density, 40-70% crystallinity and 115-130 deg.C maximum melting point measured by a differential scanning calorimeter with (B) 5-60pts.wt., preferably 10-40pts.wt. copolymer of ethylene and a 4-10C alpha-olefin in a small proportion having 0.01-50g/10min melt flow rate, 0.87-0.905g/cm<3> density, <=40 composition distribution parameter (U) determined by the formula, <=2 average chain length ratio of methylene groups and 105-125 deg.C maximum melting point.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ethylene/α-olefin copolymer composition having excellent moldability. More details include transparency, impact resistance,
The present invention relates to an ethylene/α-olefin copolymer composition suitable for packaging films with excellent blocking resistance and the like.

[Conventional technology]

Conventionally, in the packaging manufacturing field, a technique has been known in which different types of films are laminated to form a composite, thereby compensating for the drawbacks of each film. Among these, in the food packaging field, resin layers with excellent transparency, mechanical properties, rigidity, heat resistance, or gas barrier properties, such as polypropylene, polyester, nylon, cellophane, ethylene/vinyl alcohol copolymer, etc., and polyethylene, Polypropylene, ethylene
Laminated packaging bags comprising a resin layer with good transparency and heat sealability, such as vinyl acetate copolymer, are often used. To manufacture such laminated packaging bags, a method is usually adopted in which the upper and lower ends or all ends of the film are heat-sealed, and the innermost layer of the resulting bag is naturally made of a resin with good heat-sealability. layers are used.

Therefore, the film used for the innermost layer of the packaging bag must not only have good heat-sealing properties, but also must not allow the resin component to be extracted or deteriorated by the object to be packaged. In addition, in recent years, with the diversification of packaged items and usage patterns, the films conventionally used for heat-sealing layers have some problems.For example, polypropylene films have high heat-sealing temperatures and narrow spaces. , ethylene/vinyl acetate copolymer film has poor heat resistance, strength, and oil resistance, and also has acetic acid odor.
High-pressure low-density polyethylene film has the problem of poor heat-sealing strength and hot tack properties, and since both films have poor bending resistance, pinholes are likely to form in the bag during transportation and other handling, causing the contents to leak. There was a risk.

[Problem that the invention seeks to solve]

As a means to solve these drawbacks, the applicant has developed a crystalline ethylene/α-olefin copolymer, so-called L-LDPR.
It was discovered that a film obtained from a composition in which an ethylene/α-olefin copolymer with a melting point of 100°C or lower was added to has excellent low-temperature heat-sealing properties, bending resistance, impact resistance, transparency, etc., and was first proposed. (Japanese Patent Application Laid-Open No. 57-34145, Japanese Patent Publication No. 56-15664).

However, as a result of subsequent studies, although the film obtained from the above composition has excellent physical properties, the motor load and resin pressure in the extrusion molding machine are high and the moldability is slightly inferior, or depending on the application G, self-adhesion may be poor. It was found that the blocking properties and slip properties were somewhat inferior due to the presence of the polyurethane resin, and a solution to this point was desired.

The present invention aims to solve such problems,
Transparency of the film obtained by adding an ethylene/α-olefin random copolymer having a specific composition distribution and melting characteristics in place of the ethylene/1-butene random copolymer polymerized using a vanadium catalyst. It was found that a composition with improved surface properties such as blocking properties and slip properties and excellent moldability can be obtained without impairing impact resistance, low-temperature heat-sealability, bending resistance, etc., and the present invention has been realized. It was completed.

[Means for solving problems]

That is, the present invention provides: (a) Melt flow rate (ASTM D 123
8. ! ”) is 0.01 to 50 g/10m1
n, density 0.910 to 0.940 g/cnl
, crystallinity 40 to 70%, differential scanning calorimeter (D
(c) 95 to 40 parts by weight of a copolymer of ethylene having a maximum melting point of 115 to 130°C according to SC) and a small proportion of α-olefin having 4 to 10 carbon atoms, and (b) a melt flow rate (ASTM) 0123B
, II! ') is 0, Ol to 50 g/10m
1n, density 0.870 to 0.905 g/an
! , the composition distribution parameter (U) is 40 or less (however, the average chain length ratio of methylene groups is 2.0 or less, and the highest melting point measured by differential scanning calorimetry (DSC) is 105 to 125
℃ ethylene and a small proportion of α- having 4 to 10 carbon atoms
To obtain a packaging film having excellent transparency, impact resistance, low-temperature heat sealability, bending resistance, blocking resistance, and slip property, which is characterized by comprising 5 to 60 parts by weight of a copolymer with olefin. An object of the present invention is to provide an ethylene/α-olefin copolymer composition with excellent moldability.

[Function] The ethylene/α-olefin copolymer (c) (hereinafter abbreviated as crystalline copolymer (c)) used in the present invention has the following (1)
~(5).

(1) Melt flow rate (MFR: ASTM
D 1238. E) is 0.01 to 50 g/
10 m1n, preferably 0.1 to 20 g/l, more preferably 0.5 to 10 g/10
The range is o+in. If the MFR is outside the above range, the melt viscosity is either too low or too high, resulting in poor moldability.

(2) Density is 0.910 to 0.940 g/c
rA, preferably 0.915 to 0.935 g
/cl, range. Density is 0.910 g/-
If it is less than that, the mechanical properties, oil resistance, etc. when made into a film tend to be rather low, and the surface properties tend to be poor. On the other hand, 0
．． If it exceeds 940 g/cal, transparency, impact resistance, etc. will decrease.

(3) Crystallinity is in the range of 40 to 70%, preferably 50 to 65%. The degree of crystallinity is correlated with density, but if the degree of crystallinity exceeds 70%, the impact resistance will not be improved even if the low crystallinity copolymer (■) described below is added; The material is soft and has poor rigidity.

(4) The melting point measured by DSC is 1 (II or more, often 2 or 3, preferably 3, and if more than 1 is present, the highest melting point is 115 to 130°C, preferably is in the range of 115 to 125°C. If the maximum melting point is less than 115°C, the film will have poor heat resistance, and if it exceeds 130°C, the low-temperature heat sealability will be poor.

(5) A random copolymer having a substantially linear structure in which the α-olefin copolymerized with ethylene is an α-olefin having 4 to 10 carbon atoms, preferably 6 to 10 carbon atoms. Specifically, the α-olefin having 4 to 10 carbon atoms includes, for example, 1-butene, 1-hexene,
4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene and mixtures thereof. The content of the α-olefin component units constituting the crystalline copolymer (c) used in the present invention is arbitrary within the range that satisfies the density and composition distribution specified in (2) and (3) above. , usually 3 to 25 mol%, preferably 5 to 2
It is in the range of 0 mol%. Copolymers using propylene as the α-olefin are inferior in tear resistance, impact resistance, etc. α-olefins having 6 or more carbon atoms have particularly excellent mechanical strength.

Crystalline copolymer (c) having the above properties used in the present invention
is obtained by polymerizing ethylene and α-olefin in a ratio that provides the required density by a so-called medium-low pressure method using a transition metal catalyst. In this case, a molecular weight regulator such as hydrogen may be used to obtain the required melt flow rate. Polymerization can be carried out by various methods such as slurry polymerization, gas phase polymerization, and high temperature solution polymerization.

A particularly suitable manufacturing method is disclosed in Japanese Unexamined Patent Application Publication No. 1983-1981 by the present applicant.
No. 92887.

Ethylene/α-olefin copolymer a3 used in the present invention
) (hereinafter abbreviated as low crystallinity copolymer [F]) is defined by the following (a) to (f).

(a) Melt flow rate (MPR: ASTM D
123B.

E) ranges from 0.01 to 50 g/LOmin, preferably from 0.1 to 20 g/10 m1n. If the MFR is outside the above range, the melt viscosity is either too low or too high, resulting in poor moldability.

(b) Density is 0.870 to 0.905 g/a
l, preferably 0.880 to 0.900 g/
- is in the range.

If the density is less than 0.870 g/CIA, the surface properties of the film will deteriorate, while 0.905 g/cIl! If it exceeds the above range, the effect of improving impact resistance, bending resistance, low-temperature heat sealability, etc. will be inferior. The density in this invention is ASTM D
1505.

(c) The composition distribution has a composition distribution parameter (U) expressed by the following formula (1) of 40 or less, preferably 30 or less.

U=100X (Cw/Cn-1)...11) However, in the formula, Cw represents the weight average degree of branching and Cn represents the number average degree of branching.

When U exceeds 40, the composition distribution is wide and the effect of improving transparency, tear resistance, impact resistance, surface properties, etc. is poor. Cw and Cn in the present invention are values measured by the following method. That is, ethylene/α-olefin copolymer (B
), the copolymer (1) was mixed with a mixed solvent of p-kylylene and butyl cellosolve (volume ratio = 80/
After melting in step 20), a cylindrical column was filled with diatomaceous earth (trade name: Serai) coated with #560 manufactured by John Manpil (USA), and a solvent having the same composition as the mixed solvent was transferred into the column. While flowing out, the temperature inside the column was increased to 3.
The temperature was raised stepwise from 0°C to 120°C in 5°C increments, and the coated ethylene copolymer was fractionated, reprecipitated in methanol, filtered and dried to obtain a fractionated product. Next, the number of branches C per 1000 carbons of each fraction was determined by the C-NMR method, and the number of branches C and the cumulative weight fraction I (W
) follows the following log-normal distribution (Equation (2)), and Cw and Cn were determined by the least squares method.

1 (W) = However, 2 in the formula is β" = 2In (Cw/Cn) -----(3
1, and CQ is expressed as C()=Cw.Cn --.-(4).

The number of branches C determined by the C-NMR method is G and J.

Ray+ P, E, Johnson and J, R
,Knox.

Ma'cromolecules, 10 773
(1977), using the methylene carbon signal observed in the C-NMR spectrum,
It was determined from its area intensity.

(d) The average chain length ratio of methylene groups is 2.0 or less, preferably 1.7 or less.

The average chain length ratio is a parameter indicating the random structure of ethylene and α-olefin in the molecular chain of the ethylene/α-olefin copolymer (B) used in the present invention, and is
c) of the copolymer along with the composition distribution parameter (U) of
This is an important characteristic that specifies the structure of Copolymers in which the average chain length ratio of methylene groups is too large, exceeding 2.0, have excellent blocking resistance, low-temperature heat-sealing properties,
There is no effect of improving impact resistance, bending resistance, transparency, etc.

In addition, in the present invention, the average chain length ratio of methylene groups is "C
- Methylene average chain length calculated from the degree of branching measured using NMR and block methylene average chain calculated excluding cases where the number of methylenes between branches (between two adjacent branches) is 6 or less It is a value determined from the length ratio, that is, protoxymethylene average chain length/methylene average chain length.

(e) The ethylene/α-olefin copolymer (B) used in the present invention has one melting point, preferably a plurality of melting points, as measured by DSC, and if there is a plurality of melting points, the highest melting point is 105 to 100. 125°C, preferably in the range of 110 to 120°C.

Those with a maximum melting point of less than 105°C have poor surface properties,
No effect on improving blocking resistance or slipping properties. On the other hand, if the temperature exceeds 125°C, there is no effect of improving transparency, low-temperature heat sealability, impact resistance 1, or bending resistance.

Incidentally, the highest melting points of the crystalline copolymer (c) and the low crystalline copolymer (B) in the present invention were determined using DSC and sample 31.
After melting mg at 200°C for 5 minutes, the cooling rate was 10°C/ll.
The temperature was lowered to 20°C by l1n, held at this temperature for 1 minute, and then raised to 150°C at a heating rate of 10°C/min to measure the DSC endothermic curve. The peak or shoulder of is taken as the highest melting point. If the highest melting point appeared as a peak, the temperature at the peak, and if it appeared as a shoulder, the highest melting point was determined as the temperature at the intersection of the points of contact drawn at the inflection point on the high temperature side and the inflection point on the low temperature side of the shoulder.

(f) It is a random copolymer having a substantially linear structure in which the α-olefin copolymerized with ethylene is an α-olefin having 4 to 10 carbon atoms. Specifically, the α-olefin having 4 to 10 carbon atoms is, for example, 1-
Butene, 1-hexene, 4-methyl-1-pentene, 1
- Heptite Soldier 1 - u 5-7.1 - Aya and I.

It is a mixture. The content of α-olefin component units constituting the low-crystalline copolymer (ii) of the present invention is as follows (ii) to (iii) above.
It is optional within the range that satisfies the density and composition distribution specified by (d), but preferably 5 to 20 mol%.
is within the range of

The low-crystalline copolymer (2) used in the present invention has a melting point as described in (e) above, and is a polymer that itself has some crystallinity, but its degree of crystallinity is usually 5 to 60.
%, preferably in the range of 10 to 50%.

Incidentally, the crystallinity of the crystalline copolymer plane and the low crystallinity copolymer (B) used in the present invention are values determined by X-ray diffraction method. The measurement method used a straight line connecting the diffraction angles of 7° to 3165° as the background, and the rest was carried out in accordance with the method described in the following literature. S, L, Aggrwal a.
nd G, P.

Tiley, J., Polym, Sci., 18.
17 (1955).

Ethylene/α-olefin copolymer used in the present invention ■)
can be manufactured, for example, by the following method. For example, a titanium catalyst component surface obtained by treating a highly active solid component (a) with a specific surface area of 50 m/g or more containing titanium, magnesium and halogen as essential components with alcohol (b), an organic aluminum compound catalyst Using a catalyst formed from component [F]) and a halogenated hydrocarbon such as ethyl chloride, isopropyl chloride, or a halogenating agent for [F]) such as silicon tetrachloride, Ethylene and α-olefin are copolymerized to a predetermined density.At this time, organoaluminum compound catalyst component l]3
) is a halogen compound, the use of the halogen compound catalyst component (O) can be omitted.
I am familiar with 6081.

The ethylene/α-olefin copolymer composition of the present invention is
The crystalline copolymer (c) 95 to 40 parts by weight, preferably 90 to 60 parts by weight, and the low crystalline copolymer CB) 5 to 60 parts by weight, preferably 10 to 40 parts by weight.
parts by weight (100 parts by weight in total). If the amount of the low-crystalline copolymer (B) is less than 5 parts by weight, low-temperature heat-sealability, bending resistance, transparency, impact resistance, etc. will not be improved, while if it exceeds 60 parts by weight, heat resistance, rigidity, etc. , the surface properties deteriorate.

In order to obtain a film from the ethylene/α-olefin copolymer composition of the present invention, the crystalline copolymer (c) and the low-crystalline copolymer () are mixed in the above-mentioned ranges, such as V-Fenter, Ribbon Print, etc. After mixing with a renderer, Henschel mixer, tumbler blender, etc., a film can be obtained directly by a conventional film forming method, such as the T-Guy method or an inflation method, or the above mixture can be mixed with a volatilizer, kneader, Banbury mixer, etc. A method can be adopted in which the granulated material is formed into a film after being cross-wired.

In addition, the composition of the present invention may be used by adding weathering stabilizers, heat stabilizers, antistatic agents, antifogging agents, antiblocking agents, slip agents, lubricants, pigments, dyes, droplet agents, etc. to ordinary polyolefins. Various compounding agents may be blended within the range that does not impair the purpose of the present invention.

The composition of the present invention itself as a film has excellent transparency, bending resistance, and impact resistance, so it can be used alone as a packaging film such as food packaging wrap film, stretch film, shrink film, and general packaging film. It can be used as an agricultural film or a protective film, but by taking advantage of its low-temperature heat-sealability and laminating it with various base materials, packaging films suitable for various uses can be obtained.

As these base materials, any polymer having film-forming ability, paper, aluminum foil, cellophane, etc. can be used. Such polymers include, for example,
High density polyethylene, medium and low density polyethylene, ethylene/vinyl acetate copolymer, ethylene/acrylic acid ester copolymer, ionomer, polypropylene, poly-1
- Olefin polymers such as butene, poly-4-methyl-1-pentene, polyvinyl chloride, polyvinylidene chloride,
Vinyl copolymers such as polystyrene, polyacrylate, polyacrylonitrile, nylon 6, nylon 66, nylon 7, nylon 10, nylon 11, nylon 12
, polyamides such as nylon 6101 polymethaxylylene adipamide, polyesters such as polyethylene terephthalate, polyethylene terephthalate/isophthalate, polybutylene terephthalate, polyvinyl alcohol,
Examples include ethylene/vinyl alcohol copolymer and polycarbonate. These base materials can be selected as appropriate depending on the purpose and the item to be packaged. For example, if the item to be packaged is a food that is prone to corrosion, polyamide, polyvinylidene chloride, ethylene/vinyl alcohol copolymer,
Transparency, like polyvinyl alcohol and polyester
A resin with excellent rigidity and gas permeation resistance is selected. For confectionery, textile packaging, etc., polypropylene or the like with good transparency, rigidity, and water permeation resistance can be selected as the outer layer. Further, if the base material is a polymer, it may be uniaxially or biaxially stretched.

Methods for producing a composite film in which a packaging film using the composition of the present invention is laminated with the base material include various known methods such as dry lamination, extrusion lamination, lamination, sandwich lamination, and coextrusion. can be adopted.

C Effects of the Invention The ethylene/α-olefin copolymer composition of the present invention has excellent moldability with low motor load and resin pressure in the extrusion molding machine, and the resulting film has good transparency and impact resistance. without impairing properties, low-temperature heat sealability, bending resistance, etc.
The surface properties such as blocking resistance and slip properties, as well as the welding of the film, have been improved, so these properties can be utilized for various packaging applications. Due to its excellent bending resistance, it is suitable for packaging for watery foods, packaging for oily foods such as curry, soup, butter, and cheese, and for packaging for transporting liquids.

〔Example〕

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way unless the gist of the invention is exceeded.

Example 1 <Catalyst Preparation> Under a nitrogen atmosphere, 1 mol of commercially available anhydrous magnesium chloride was suspended in dehydrated and purified hexane 21, 6 mol of ethanol was added dropwise over 1 hour with stirring, and the mixture was reacted for 1 hour at room temperature. . 2.6 mol of diethylaluminum chloride was added dropwise to this at room temperature, and stirring was continued for 2 hours. Next, after adding 6 moles of titanium tetrachloride, the system was heated to 80° C. and the reaction was carried out with stirring for 3 hours. The solid portion after the reaction was separated and washed repeatedly with purified hexane. The solid (A-
The composition of 1) was as follows.

3.7 67.0 20.0 0.4 4.8 Next,
To 50 mmol of Ti in A-1 suspended in purified hexane, 500 mmol of ethanol was added at room temperature, the temperature was raised to 80° C., and the mixture was reacted for 1 hour. After the reaction, the temperature was lowered to room temperature, 150 mmol of triethylaluminum was added, and the reaction was carried out with stirring for 1 hour. The solid portion after the reaction was washed repeatedly with purified hexane. The composition of the catalyst (B-1) thus obtained was as follows.

2.8 59.3 13.7 0.5 23.6*) The produced solid was decomposed and extracted with 1120-acetone, and then quantified as ethanol using gas chromatography.

Polymerization> Using a continuous polymerization reactor with an internal volume of 200 fi, dehydrated and purified hexane was used at 10012/hr, ethylaluminum sesquichloride was used at 15 mmol/hr, and the catalyst (B-1) obtained above was converted into Ti. 1.0 mmol/hr
Ethylene was fed at a rate of 10 kg/hr and 1-butene was fed at a rate of 33 kg/hr at the same time in the polymerization vessel.

2QI hydrogen! /hr, polymerization temperature: 150°C, total pressure: 30 kg/cni, residence time: 1 hour, copolymer concentration with respect to solvent hexane: 100
Copolymerization was carried out under conditions such that g/j2. Catalytic activity is 1
This corresponded to 3,000 g-copolymer/mmol-Ti.

The obtained ethylene/1-butene copolymer (EBC-1'
) physical properties are MFR: 2.2g/10m1n, density 0.889g/cm2, U: 23, average chain length ratio of methylene groups: 1.2.6, highest melting point: 11B, 2℃ (
There are other peaks at 72.0°C and 103.5°C), crystallinity: 18.4% and 1-butene content: 9.7 mol%
Met.

<Film forming> EBC-1: 20 parts by weight and MFR: 2.3 g/10
m1n, density: 0.921 g/cm2, crystallinity:
51.0%, maximum melting point: 123.2°C (104%
．． peaks at 0°C and 118.7°C) and 4-methyl-
1-pentene content: 2.4 mol% ethylene/4-methylene-1-pentene copolymer (EMC-1): s
o parts by weight in a Henschel mixer, and then molded to a width of 230 m using a commercially available tubular film molding machine for polyolefins.
A film with a thickness of 30 μm and a thickness of 30 μm was molded. The resin temperature during molding was 180°C, the extruder was 50+nmφ, the screw rotation speed was 40rp+i, the diameter of the goose was 100mmφ, and the inside of the goose slit was 0.8mm.

It was carried out using two stages of cooling air rings (first nearing - second nearing = 380 mm). The physical properties of this film were measured by the following method.

Haze (%): ASTM D 1003 Tear strength (Elmendorf: kg/cm): JIS Z 170
2 Impact strength (kg-CIII/cI11): ASTM
D 3420 Blocking degree: 20c11 x 25CII from film
A test piece of No. I was cut out, two films were stacked on top of each other, and the test pieces were left under a load of 10 kg at 40° C. for 24 hours, and then tested using an autograph manufactured by Konsei Seisakusho in accordance with the method of ASTM D-1893.

Friction coefficient: ASTM 0 1894 Extrusion moldability: When the screw rotation speed is 4 Orpm in a film molding machine,
Resin pressure (kg/crA G ) and motor load were measured.

Film appearance: The appearance of the film weld area was visually judged.

◎; Weld is not noticeable ○; Weld is slightly noticeable The results are shown in Table 1.

Example 2 Instead of EMC-1 used in Example 1, l'lFR:
1.6 g/10m1n, density: 0.935 g
/ crA, crystallinity: 57.2%, melting point: 12
4.2°C (single peak) and 1-putene content: 2.0
Mol% of ethylene/1-butene copolymer (EBC-2)
The same procedure as in Example 1 was carried out except that . The results are shown in Table 1.

Example 3 Instead of EMC-1 used in Example 1, MFR: 0.
90g/10m1n, density: 0.930g/
ad, crystallinity: 53.7%, highest melting point: 123
．． 9°C (there are other peaks at 110.0°C and 121.3°C) and 1-octene content: 2.1 mol% ethylene.
The same procedure as in Example 1 was conducted except that 1-octene copolymer (EOC-1') was used. The results are shown in Table 1.

Comparative Example 1.2 MFR obtained using a vanadium catalyst instead of EBC-1 used in Examples 1 and 2: 3.9 g
/10mln, density: 0.886g/cm2, maximum melting point: 68°C (single peak), crystallinity: 8.3%, and 1-butene content: 10.5 mol% ethylene/1-
The same procedure as Example 1 and Example 2 was carried out except that butene random copolymer (EBC-3) was used. The results are shown in Table 1.

Claims (1)

[Claims] (1) (a) Melt flow rate (ASTM D123
8.E) is 0.01 to 50g/10min, density is 0.910 to 0.940g/cm^2, crystallinity is 40 to 70%, and the highest melting point by differential scanning calorimeter (DSC) is 115 to 130. A copolymer of ethylene and a small proportion of α-olefin having 4 to 10 carbon atoms (
A) 95 to 40 parts by weight, and (b) melt flow rate (ASTM D1238, E
) is 0.01 to 50g/10min, density is 0.8
70 to 0.905 g/cm^2, composition distribution parameter (U) is 40 or less {however, U = 100 x (weight average velocity / number average degree of branching - 1)} average chain length ratio of methylene groups is 2.0 or less , a copolymer of ethylene and a small proportion of an α-olefin having 4 to 10 carbon atoms, which has a maximum melting point of 105 to 125°C as measured by differential scanning calorimetry (DSC) 5 to 6
An ethylene/α-olefin copolymer composition comprising 0 parts by weight.