JP2829365B2 - Resin composition for film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition useful as a packaging film, and more particularly to a resin composition suitable for a material having a stretching action before or during packaging.

[0002]

2. Description of the Related Art In recent years, due to the streamlining of physical distribution, a band-shaped plastic film is wound around an object to be packaged while being stretched by a stretch method on an accumulated cardboard box, can, food or the like. So-called stretch packaging is widely performed. This stretch packaging also
Conventionally, a method of stretching a film to about 30% and wrapping the film has been used, but in recent years, a method of stretching a film to about 250 to 300% at the time of wrapping has begun to be widely used from the viewpoint of resource saving.

[0003] Initially, thin films of vinyl chloride resin were used as these stretch packaging films, but due to food hygiene problems caused by vinyl chloride monomers and plasticizers, olefin-based resin films such as EVA were used. Have been used, but are not yet fully satisfactory.

For example, such stretch packaging film is disclosed in Japanese Utility Model Publication No. 56-74737 and Japanese Patent Publication No. Sho 5-5.
In JP-A-5-41298 and JP-B-2-12187, linear low-density polyethylene (L-LDPE) or a composition of linear low-density polyethylene and ethylene-vinyl acetate copolymer (EVA) is used. Films have been proposed.

[0005]

In a stretch wrapping film, it is important that the film has a tackiness (self-adhesiveness) and an elastic recovery force in a wrapped state. Depends greatly on the properties of the resin itself, but also considerably on the degree of stretching. The tackiness depends on the optical properties (appearance) of the film. In the above-mentioned conventional film, at the time of the above-mentioned stretch packaging, especially in stretch packaging performed at a high stretching ratio, at the time of packaging, the film breaks, stretching unevenness occurs, and the above-mentioned characteristics become unsatisfactory or the appearance becomes poor. It may be defective. In addition to the above, it is known that a film is stretched to impart various properties to the film before packaging (for example, Japanese Patent Publication No. 2-14895). However, polyethylene is easily necked and stretchable due to resin properties. However, there are drawbacks such as poor film breakage and unevenness in stretching.

Accordingly, an object of the present invention is to eliminate the above-mentioned drawbacks of the conventional olefin resin film for stretch packaging, and to provide excellent stretching performance.
It is an object of the present invention to provide a resin composition capable of obtaining a film with extremely little unevenness in stretching.

Another object of the present invention is to provide a stretch packaging film having improved optical properties such as improved suitability for stretch packaging, stretchability and transparency, and mechanical properties such as impact resistance, and a resin composition used therefor. To provide.

[0008]

According to the present invention, (A)
Density (DA) in the range of 0.900 to 0.917 g / cc, especially 0.900 to 0.915 g / cc, and molecular weight distribution (MW / MN, MA) of 2.5 to 5.0, especially 2.5 A low-density polyethylene having an α-olefin content of from 5 to 4.5 and comprising an α-olefin having 5 or more carbon atoms, and (B) a density (DB) of 0.916 to 0.940 g / cc, particularly 0.918 to 0.925 g
/ Cc range and molecular weight distribution (MW / MN, MB) is 5
And a linear low-density polyethylene having an α-olefin component of 4 to 4 carbon atoms in an amount of 20/80 to 20/80, especially 6 to 10.
In the range of 70 to 30 / (DB−DA) * 10
0 is 0.3 or more, particularly 0.5 or more, and the melt flow rate (MFR) as a whole is 0.1 or more.
3 to 5.0 g / 10 min, especially 0.5 to 3.0,
A density of 0.905 to 0.930 g / cc, especially 0.9
05 to 0.925 g / cc and molecular weight distribution (MW / M
N) is in the range of 3.5 to 5.5, shows three or more peaks by differential scanning calorimetry (DSC) measurement, has a maximum melting point peak (T1) of 118 to 125 ° C., and has a maximum melting point peak height. (HT1) / peak height (HT2) of the next melting point (T2) is 1.0 or less, especially 0.8 or less, and the peak of the highest melting point peak height (HT1) / the lowest melting point (Tn). A resin composition for a film is provided which has a thermal property of having a height (HTn) ratio of 2.0 or less, particularly 1.5 or less.

The linear low-density polyethylene (A) used in the present invention has two or more peaks measured by a differential scanning calorimeter (DSC), and has a maximum melting point peak (T1) of 118 to 1
At 25 ° C., it is preferable to have a thermal characteristic in which the ratio of the maximum melting point peak height (HT1) / the next melting point (T2) peak height (HT2) is 1.0 or less. Preferably, the linear low-density polyethylene (A) shows three or more peaks by differential scanning calorimetry (DSC) measurement, and has a maximum melting point peak (T1).
Is 118-122 ° C. and the maximum melting point peak height (HT1
) / The peak height (HT2) of the next melting point (T2) is 0.8 or less, and the maximum melting point peak height (HT1) /
The ratio of the peak height (HTn) of the minimum melting point (Tn) is 1.5
It has the following thermal properties: The linear low-density polyethylene (A) has a content of 0.3 to 5.0 g / 10 mi.
The melt flow rate (MFR) of n, especially 0.5 to 3.0 g / 10 min, and the amount of n-decane soluble component is preferably 20% by weight or less, particularly preferably 15% by weight or less.

[0010] The linear low-density polyethylene (B) is
0.1 to 1.5 g / 10 min, especially 0.1 to 1.
It preferably has a melt flow rate (MFR) of 0 g / 10 min.

According to one aspect of the present invention, there is provided a stretch packaging film comprising the linear low-density polyethylene composition.

[0012]

The linear low-density polyethylene is a random copolymer having a substantially linear and short-chain branch obtained by copolymerizing ethylene and an α-olefin having 3 to 10 carbon atoms. Is generally 0.910 to 0.9
It is in the range of 40 g / cc. In the present invention, among the linear low-density polyethylenes, two kinds of components having different characteristics, namely, a linear low-density polyethylene (A) having a relatively low density and a narrow molecular weight distribution, and a relatively high density and a wide molecular weight The composition is blended with the linear low-density polyethylene (B) having a distribution at the above-mentioned quantitative ratio to obtain a composition having various physical properties within the above-mentioned ranges. When this composition is used for the production of a film, the stretchability of the film is remarkably improved, the suitability for stretch packaging such as tackiness and elastic recovery is remarkably improved, and further, optical properties such as transparency, impact resistance, etc. Can be improved in mechanical properties.

In the present invention, a linear low-density polyethylene (A) having a relatively low density and a narrow molecular weight distribution and a linear low-density polyethylene (B) having a relatively high density and a wide molecular weight distribution are respectively selected. The combination is because these combinations remarkably improve the stretchability and the suitability for stretch packaging, and if only one of the linear low-density polyethylene (A) or (B) is used, Both properties and suitability for stretch packaging are unsatisfactory (see Comparative Examples 1 and 2). This is due to the difference in density between the two [(DB-DA) *
Is smaller than 0.3 (see Comparative Example 8).

One linear low-density polyethylene (A) is
It is important to include a component having 5 or more carbon atoms as α-olefin from the viewpoint of mechanical properties such as impact resistance of the film, and those having 4 or less carbon atoms are inferior in mechanical properties (see Comparative Example 3). . In the other linear low-density polyethylene (B), a component having 4 or more carbon atoms is allowed as α-olefin. It is also important that the linear low-density polyethylene (A) has a relatively low density and a narrow molecular weight distribution. If the molecular weight distribution is wide, the optical properties and mechanical properties deteriorate. (See Comparative Example 5). Similarly, it is important that the linear low-density polyethylene (B) has a relatively high density and a broad molecular weight distribution. If the molecular weight distribution is narrow, the stretchability and suitability for stretch packaging are reduced. (See Comparative Example 6).

It is also important that the composition of the present invention contains both polyethylene components (A) and (B) in the above-mentioned ratios in view of the above-mentioned various properties. ,
Stretchability and suitability for stretch packaging are reduced, while component (B)
Is small, the optical properties and mechanical properties decrease (see Comparative Example 7). The thermal properties of the composition are also important, such as those having a double peak in the DSC curve, HT1 / HT2
If the ratio is larger than 1.0, the optical properties and mechanical properties decrease (see Comparative Examples 3 and 4).

In summary, the occurrence of necking is prevented when the film is stretched before or during packaging.
Furthermore, the occurrence of film breakage and stretching unevenness is prevented,
The stretchability is improved, the suitability for stretch packaging is improved, and these packaging films have excellent properties such as transparency and mechanical strength, particularly impact strength, in addition to the above-mentioned properties.

[0017]

The linear low-density polyethylene used in the present invention is an α-olefin having 4 or more carbon atoms, for example, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1. 1, contains α-olefin such as decene-1. The content of ethylene in the linear low-density polyethylene is such that the density of the copolymer falls within the range described above. In general, the content of ethylene is 0.5 to 15 mol%, especially 1.5 to 10 mol%.
Is desirably within the range. The α-olefin constituting the linear low-density polyethylene (A) is preferably C5 to C10, particularly preferably C5 to C8, while the α-olefin constituting the linear low-density polyethylene (B) is C4 to C4.
C10, especially C4 to C8, are preferred.

The linear low-density polyethylene (A) used in the present invention preferably has the above-mentioned thermal properties, melt flow rate and n-decane soluble component content for the purpose of the present invention. This linear low density polyethylene (A)
Is an additional feature that it has a narrow composition distribution, that is, the copolymer composition is homogeneous, as indicated by the above-mentioned thermal properties and the amount of n-decane soluble component.

This linear low-density polyethylene (A) is described in JP-A-60-88016,
A titanium catalyst component (a), an organoaluminum compound catalyst component (b) obtained by treating a highly active solid component containing titanium, magnesium and halogen as essential components and having a specific surface area of 50 m ^ 2 / g or more with alcohol; It is obtained by copolymerizing ethylene and α-olefin so as to have a predetermined density using a catalyst formed from the halogen compound catalyst component (c).

The linear low-density polyethylene (B) used in the present invention preferably has the above-mentioned melt flow rate for the purpose of the present invention. This linear low-density polyethylene (B) can be obtained by a usual method for producing a linear low-density polyethylene, but those having an MB of 5 or more can be obtained by a two-stage polymerization method, that is, separately separating the low- and high-molecular-weight components. It is produced by a method in which it is produced by a polymerization vessel and then combined.

To form a film using the composition of the present invention, the linear low-density polyethylene (A) and (B) are
At a ratio in the above range, the mixture is mixed with a V-blender, a ribbon blender, a Henschel mixer, a tumbler blender, or the like, or further kneaded with an extruder, a kneader, a Banbury mixer, or the like, and then granulated. , A water-cooled type) or a T-die film forming method. In the case of the inflation film forming method, the MF of the composition
R is preferably 1.8 g / 10 min or less, and in the case of the T-die film forming method, the MFR of the composition is preferably 1.9 g / 10 min or more.

The composition of the present invention contains a tackifier (eg, liquid polyisobutylene, liquid polybutadiene, ethylene vinyl acetate polymer), a heat stabilizer, a slip agent (eg, erucamide, oleamide, stearamide, etc.). , Antifogging agents (various surfactants), weather stabilizers, antistatic agents, antiblocking agents, pigments, dyes, etc., various polyolefins, and various additives used in stretch packaging films, alone or in combination of two or more Can be blended.

The film of the present invention can be used as various packaging films in the form of a uniaxial or biaxially stretched film, or used as a stretch packaging film in the form of an unstretched or uniaxial or biaxially stretched film. Can be.

In the present specification, various physical properties were measured by the following measuring methods. Density: According to ASTM D-1505. Molecular weight distribution (MW / MN): by gel permeation chromatography. Melt flow rate (MFR): AST
According to MD-1238E. Thermal properties by DSC: As shown in FIG. 1, the line connecting the points of 60 ° C. and 130 ° C. of the endothermic curve of the differential scanning calorimeter (DSC) was used as a baseline, and the highest melting point peak among each melting point peak was determined. T1, the next melting point peak is T2,... The lowest melting point peak is Tn, and the height from the baseline to the peak is HT1, HT2,.
Find the peak ratio as n. Amount of n-decane soluble component:
10 g of polyethylene was dissolved in 1 l of n-decane at 130 ° C. in the presence of 2,5-tertbutyl-4-methylphenol, a heat-resistant stabilizer, and kept at 130 ° C. for 1 hour.
The weight of the polyethylene precipitated when cooled to 23 ° C. at a cooling rate of / 10 min is determined and calculated from this weight.

[0025]

The present invention will be described more specifically with reference to the following examples. The evaluation in each example was performed as follows. (Stretchability) Using a roll-type wet stretching apparatus shown in FIG. 2, a water tank 3 with a temperature controller is arranged between the first rotating roll 1 and the second rotating roll 2, and the film 4 is placed in a water bath for the first time. Stretching was performed due to the difference in peripheral speed between the rotating roll 1 and the second rotating roll 2. The water temperature was 50 ° C., the peripheral speed of the first rotating roll was 20 m / min, and the stretching ratio was 3 times. Rating: ＝ = no stretching unevenness, Δ = slight stretching unevenness, × = marked stretching unevenness. (Stretch aptitude) Using a power stretch machine (Run Wrapper, V series) manufactured by Lantec (USA), stretching roll ratio 4.0
(The film was stretched by about 3.5 times), the film was stretched, packaged, and evaluated according to the following criteria. Rating: ＝= No problem in wrapping property and no stretching unevenness was observed.

Δ = Wrapping property is not a problem, but stretching unevenness occurs. (Haze) According to JIS K6714. The higher the number, the poorer the transparency. (Dart impact strength) ASTM D1709 (A
Method). The larger the number, the greater the defense strength.

Example 1 MFR 2.2 g / 10 min, DA 0.910 g /
cc, MA 3.5 and n-decane soluble component amount 2.5
T1 = 120 DEG C., HT1 / HT2 = 0.5% by weight
5. DS with HT1 / HTn = 0.58 and 3 peaks
C. Ethylene-4-methylpentene-1 having thermal properties
(4MP-1) copolymer (A1) and MFR 0.6 g
/ 10 min, DB 0.921 g / cc and MB
7.6 ethylene-butene-1 (C4) copolymer (B1
) Were blended in a 50/50 weight ratio.

This blend has an MFR of 1.2 g / l
0 min, density 0.916 g / cc and MW / MN
At 4.6, T1 = 121 DEG C., HT1 / HT2 = 0.7
0, HT1 / HTn = 1.01 and DS with 3 peaks
C had thermal properties.

This blend was formed into a film under the following conditions. (Film forming conditions) A modern delcer 50 mmφ blown film forming machine was used as the forming machine, and the die was 150 mm.
A spiral die having a diameter of 2 mm and a lip width of 2 mm was used, and a screw having an L / D of 28 and a full-flight type metering was used as a 2-gap type air ring. The molding temperature is C1 / C2 / A / D
1 / D2 = 160/170/180/180/180 ° C
And Automated height: 20 cm, take-off speed: 20 mm / m
in, film dimensions: 25 mm thickness x 500 mm width.

The results obtained are shown in Tables 1 and 2.

Example 2 In Example 1, MF was used in place of the copolymer (A1).
R 1.9 g / 10 min, DA 0.905 g / c
c, MA 3.3 and n-decane soluble component amount 6.1
T1 = 119 DEG C., HT1 / HT2 = 0.4% by weight
5. DS with HT1 / HTn = 0.33 and 3 peaks
C An ethylene-pentene-1 (C5) copolymer having thermal properties (A2) is used, and the blending ratio of the two (A2 / B1) is used.
Was prepared in the same manner as in Example 1 except that the weight ratio was changed to 30/70.

This blend has an MFR of 0.9 g / 1.
0 min, density 0.916 g / cc and MW / MN
6.0, T1 = 123 DEG C., HT1 / HT2 = 0.8
2. DS with HT1 / HTn = 1.41 and 3 peaks
C had thermal properties. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Example 3 MFR 1.8 g / 10 min, DA 0.910 g /
cc, MA 3.7 and n-decane soluble component amount 2.3
T1 = 120 DEG C., HT1 / HT2 = 0.5% by weight
7, DS with HT1 / HTn = 0.61 and 3 peaks
C. Ethylene-4-methylpentene-1 having thermal properties
(4MP-1) copolymer (A3) and MFR 1.3 g
/ 10 min, DB 0.925 g / cc and MB
6.6 ethylene-4-methylpentene-1 (4MP-
1) The copolymer (B2) was blended in a 50/50 weight ratio.

This blend had an MFR of 1.6 g / 1.
0 min, density 0.918 g / cc and MW / MN
4.9, T1 = 121 DEG C., HT1 / HT2 = 0.6
9, DS with HT1 / HTn = 1.05 and 3 peaks
C had thermal properties. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Example 4 MFR 2.9 g / 10 min, DA 0.911 g /
cc, MA 3.8 and n-decane soluble component amount 2.1
T1 = 121 DEG C., HT1 / HT2 = 0.7% by weight
1. DS with HT1 / HTn = 0.51 and 3 peaks
C. Ethylene-4-methylpentene-1 having thermal properties
(4MP-1) copolymer (A4) and 0.5 g of MFR
/ 10 min, DB 0.920 g / cc and MB
8.2 ethylene-butene-1 (C4) copolymer (B3
) Were blended in a weight ratio of 60/40.

This blend has an MFR of 2.1 g / 1.
0 min, density 0.915 g / cc and MW / MN
At 5.2, T1 = 122 DEG C., HT1 / HT2 = 0.7
3, DS with HT1 / HTn = 1.10 and 3 peaks
C had thermal properties. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Comparative Example 1 MFR 2.2 g / 10 min, DA 0.923 g /
cc, MA 3.5 and n-decane soluble component amount 2.5
T1 = 122 DEG C., HT1 / HT2 = 0.8% by weight
9, DS with HT1 / HTn = 1.35 and 3 peaks
C. Ethylene-4-methylpentene-1 having thermal properties
A film was produced in the same manner as in Example 1 except that the (4MP-1) copolymer (A5) alone was used. The obtained results are shown in Tables 1 and 2.

Comparative Example 2 MFR 1.0 g / 10 min, DA 0.915 g /
9. cc, MA 4.3 and n-decane soluble component amount
Ethylene-4-methylpentene-1 (4) with 5% by weight and T1 = 124 and one peak DSC thermal properties
MP-1) A film was produced in the same manner as in Example 1 except that the copolymer (A6) was used alone. Table 1 shows the obtained results.
And Table 2.

Comparative Example 3 In Example 1, MF was used in place of the copolymer (A1).
R 2.5g / 10min, DA 0.908g / c
c, MA 3.2 and n-decane soluble component amount 1.6
T1 = 118 DEG C., HT1 / HT2 = 0.4% by weight
8, DS with HT1 / HTn = 0.30 and 3 peaks
A blend was prepared in the same manner as in Example 1 except that an ethylene-butene-1 (C4) copolymer (A7) having C thermal characteristics was used.

This blend had an MFR of 1.4 g / 1.
0 min, density 0.915 g / cc and MW / MN
At 4.4, T1 = 120 DEG C., HT1 / HT2 = 0.6
7, DS with HT1 / HTn = 0.99 and 3 peaks
C had thermal properties. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Comparative Example 4 In Example 1, MF was used in place of the copolymer (A1).
R 1.2g / 10min, DA 0.908g / c
c, ethylene 4.6- and ethylene-4-methylpentene-1 (4M) having 25% by weight of n-decane soluble component and having DSC thermal characteristics of T1 = 123 DEG C. and one peak
P-1) A blend was produced in the same manner as in Example 1 except that the copolymer (A8) was used.

This blend has an MFR of 0.9 g / 1.
0 min, density 0.915 g / cc and MW / MN
At 5.9, it had a DSC thermal profile with T1 = 124 DEG C., HT1 / HT2 = 6.9 and two peaks. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Comparative Example 5 In Example 1, MF was used in place of the copolymer (A1).
R 0.7g / 10min, DA 0.914g / c
c, ethylene 7.7 having a thermal conductivity of 7.7 at 7.7 ° C., HT 1 / HT 2 = 7.4 and HT 1 / HT 2 = 7.4 at 21% by weight of MA, 7.7 and n-decane soluble component of 21% by weight.
A blend was prepared in the same manner as in Example 1 except that the methylpentene-1 (4MP-1) copolymer (A9) was used.

This blend has an MFR of 0.7 g / 1.
0 min, density 0.918 g / cc and MW / MN
At 7.7, it had a DSC thermal profile with T1 = 124 DEG C., HT1 / HT2 = 7.4 and two peaks. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Comparative Example 6 In Example 1, MF was used in place of the copolymer (B1).
R 2.2 g / 10 min, DB 0.925 g / cc
And MB 4.2 ethylene-4-methylpentene-1
A blend was produced in the same manner as in Example 1 except that the (4MP-1) copolymer (B4) was used.

This blend had an MFR of 2.2 g / l
0 min, density 0.916 g / cc and MW / MN
3.9, T1 = 122 DEG C., HT1 / HT2 = 0.8
1. DS with HT1 / HTn = 0.95 and 3 peaks
C had thermal properties. Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Comparative Example 7 In Example 1, the mixing ratio (A1 / B1) of the two was changed to 1
A blend was produced in the same manner as in Example 1 except that the weight ratio was 0/90. This blend has an MFR of 0.
7g / 10min, density 0.920g / cc and MW
/ MN 7.1, T1 = 121 DEG C., HT1 / HT2 =
It had a DSC thermal characteristic of 0.65, HT1 / HTn = 1.50 and three peaks.

Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

Comparative Example 8 A blend was prepared in the same manner as in Example 3 except that the copolymer (A5) of Comparative Example 1 was used instead of the copolymer (A3). This blend is M
FR 1.8g / 10min, density 0.925g / c
c and MW / MN 4.2, T1 = 123 DEG C., HT1
/HT2=1.05, HT1 / HTn = 1.26 and DSC thermal characteristics with 3 peaks.

Using this blend, a film was produced in the same manner as in Example 1. The obtained results are shown in Tables 1 and 2.

In Examples 1 to 4, stretchability, suitability for stretch packaging, optical characteristics (haze) and strength (dirt impact) are good, but in Comparative Examples, films satisfying all of these cannot be obtained. Comparative Example 1 is a film in which a material other than the density but in the range of linear low-density polyethylene (A) is formed into a film alone. This film has good strength and optical properties but poor stretchability. In Comparative Example 2, a film having a density in the range of the linear low-density polyethylene (A) alone was formed into a film, but this film was still insufficient in stretchability and was particularly poor in optical characteristics.

In Comparative Example 3, the comonomer of the linear low-density polyethylene (A) was C4, but this was particularly inferior in strength. In Comparative Example 4, the DSC thermal properties of the blend are outside the scope of the present invention, but this is inferior in optical properties. Comparative Example 5 shows the MW of linear low-density polyethylene (A).
/ MN is out of the range of the present invention, and the DSC
Thermal properties are outside the scope of the present invention, but they are inferior in optical properties and strength.

In Comparative Example 6, although the MW / MN of the linear low-density polyethylene (B) is out of the range of the present invention, it is inferior in stretchability. In Comparative Example 7, the blend ratio of both resins is out of the range of the present invention, but this is inferior in optical characteristics. In Comparative Example 8, although the density difference, that is, (DB−DA) * 100 is out of the range of the present invention, the stretchability is inferior.

According to the present invention, two kinds of components having different properties, namely, a linear low-density polyethylene (A) having a relatively low density and a narrow molecular weight distribution, and a relatively high density, By blending with the linear low-density polyethylene (B) having a wide molecular weight distribution in the above-mentioned quantitative ratio to obtain a composition having various physical properties within the above ranges, when this composition is used for producing a film, The stretchability of the film was significantly improved, the suitability for stretch packaging such as tackiness and elastic recovery was significantly improved, and the optical properties such as transparency and the mechanical properties such as impact resistance were improved. .

[0055]

[Table 1]

[0056]

[Table 2]

[Brief description of the drawings]

FIG. 1: Differential scanning calorimeter (D) of linear low density polyethylene
It is a diagram which shows the peak and peak height in the endothermic curve of SC).

FIG. 2 is a schematic layout diagram of a film stretching apparatus used in Examples.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 23/00-23/36

Claims (7)

(57) [Claims] (A) A density (DA) of 0.900 to 0.
917 g / cc and molecular weight distribution (MW / MN, M
(A) a linear low-density polyethylene having an α-olefin component of at least 5 carbon atoms in the range of 2.5 to 5.0, and (B) a density (DB) of 0.916 to 0. .940 g / c
c and a linear low-density polyethylene having a molecular weight distribution (MW / MN, MB) in the range of 5 to 20 and an α-olefin component of an α-olefin having 4 or more carbon atoms, and a weight of A / B. The ratio is in the range of 20/80 to 70/30 and the value of (DB-DA) * 100 is 0.3 or more, and the overall melt flow rate (MFR) is 0.3 to 5. 0 g / 10 min, density of 0.905 to 0.930 g / cc, molecular weight distribution (MW / MN) in the range of 3.5 to 5.5, and 3 or more measured by differential scanning calorimetry (DSC) And the highest melting point peak (T1) is 118-125 ° C.
The ratio of the highest melting point peak height (HT1) / the next melting point (T2) peak height (HT2) is 1.0 or less, and the highest melting point peak height (HT1) / lowest melting point (Tn) peak height. A resin composition for a film, having a thermal characteristic wherein the ratio of (HTn) is 2.0 or less. 2. The linear low-density polyethylene (A) has two or more peaks as measured by a differential scanning calorimeter (DSC), has a maximum melting point peak (T1) of 118 to 125 ° C., and has a maximum melting point peak height (T1). 2. A composition according to claim 1 having thermal properties wherein the ratio of (HT1) / peak height (HT2) of the next melting point (T2) is 1.0 or less. 3. The melt flow rate (MF) of the linear low density polyethylene (A) is from 0.3 to 5.0 g / 10 min.
A composition according to claim 1 having R). 4. The method according to claim 1, wherein the linear low-density polyethylene (A) is 0.90.
Density (DA) ranging from 0 to 0.915 g / cc and molecular weight distribution ranging from 2.5 to 4.5 (MW / MN, M
A composition according to claim 1, comprising A). 5. A melt flow rate (MF) of the linear low density polyethylene (B) of 0.1 to 1.5 g / 10 min.
A composition according to claim 1 having R). 6. The linear low-density polyethylene (B) has a content of 0.91.
Density (DB) in the range of 8 to 0.925 g / cc and 6
2. A composition according to claim 1, having a molecular weight distribution (MW / MN, MB) in the range of from 10 to 10. 7. A stretch packaging film comprising the composition according to claim 1.