KR20010072727A - Blends containing linear low density polyethylene, high density polyethylene, and low density polyethylene particularly suitable for extrusion coating and films - Google Patents

Abstract

Novel compositions of three or more different polyethylene-based components are provided. Blends include linear low density polyethylene, high density polyethylene and low density polyethylene. The composition can be used for extrusion coating, the manufacture of cast or blown films, and other applications such as laminates.

Description

BLENDS CONTAINING LINEAR LOW DENSITY POLYETHYLENE, HIGH DENSITY POLYETHYLENE, AND LOW DENSITY POLYETHYLENE PARTICULARLY SUITABLE FOR EXTRUSION COATING AND FILMS}

Conventional polyolefin blends containing linear low density polyethylene as a component are useful for certain extrusion coatings. One such conventional blend is Dow Chemical's Dowlex 3010 linear low density polyethylene containing at least 80% by weight of linear low density polyethylene. Examples of extrusion coating applications are structures such as flexible polymeric film / paper packaging for food and metalized polymeric film baluns. Linear low density polyethylene components in conventional blends have strong heat sealability (coating-to-coating); Strong tensile properties of the coating; Strong tear resistance of the coating; High resistance to missiles, darts or impacts of the coating; Puncture resistance of the coating; And stress cracking resistance of the coating. This property is generally not achievable with polyolefin blends that do not contain linear low density polyethylene. However, such conventional blends containing low density linear polyethylene present certain undesirable processing problems.

Conventional blends containing high levels, ie, at least 80% by weight of linear low density polyethylene, generally require excessive power (extruder motor driven watts) to be extruded during the extrusion coating operation. Often, the production speed of the extrusion coating operation must be slowed down not to exceed the limits of the extruder drive motor. In many cases, productivity is too low and results in economic losses.

Moreover, conventional blends containing high levels, i.e., at least 80% by weight, of linear low density polyethylene generally exhibit excessive extrudate edge beads exhibited by excessive neck-in of the molten extrudate. This is a problem already known to those skilled in the extrusion coating art. Excess edge beads must be cut and removed as waste. Otherwise, the final coated structure does not exhibit uniform thickness.

It is evident that the use of polyolefin compositions containing linear low density polyethylene as a component for extruding with significantly lower power requirements and significantly less edge beads is desirable in extrusion coating operations. Moreover, it is desirable for the same polyolefin composition containing linear low density polyethylene as a component to possess the desired coating properties exhibited by conventional two-component polyolefin blends containing linear low density polyethylene as the main component of the two components. Properties include strong heat sealability (coating-to-coating); Strong tensile properties of the coating; Strong tear resistance of the coating; High resistance to missiles, darts or impacts of the coating; Puncture resistance of the coating; And stress crack resistance of the coating.

Summary of the Invention

The inventors have discovered an improved extrusion coated polyolefin composition comprising unexpected linear low density polyethylene, high density polyethylene and low density polyethylene. The composition of the present invention is preferably extruded with lower power requirements (extruder driven motor watts) than conventional two-component blends containing linear low density polyethylene. This occurs even when the composition of the present invention requires significantly more thermal energy per unit mass for melting than is required by conventional blends. The composition of the present invention exhibits significantly less neck-in (less edge beads) than is seen with conventional compositions.

The composition according to the invention is a polyolefin blend comprising the following three or more components. The first component is generally a linear low density polyethylene that provides coat-to-coat heat seal strength, toughness, tear resistance and puncture resistance. In general, these properties are essentially the same as those of conventional compositions. The second component is generally a high density polyethylene copolymer that provides tensile strength and stress cracking resistance. These properties are generally substantially the same as conventional compositions. The third component is generally a low density polyethylene homopolymer that lowers the neck beads of the molten extrudate to reduce edge beads. In general, these neck-in properties are superior to conventional compositions. Moreover, the third component also generally provides good wetting of the substrate surface on which the blend is coated for good coating-to-substrate bonding. Accordingly, the present invention containing less linear low density polyethylene than conventional compositions is typically used without the loss of coating properties expected due to the reduction of linear low density polyethylene.

The present invention also relates to an improved extrusion coating process comprising the use of the abovementioned compositions of at least linear low density polyethylene, high density polyethylene and low density polyethylene. Moreover, the present invention also relates to coated articles or composites comprising uncoated or uncoated substrates, preferably having an electrospray composition coated on the substrate by an extrusion coating method. The primer used to provide the bond to the substrate is preferably a water soluble primer, more preferably a polyethyleneimine primer. Moreover, the present invention includes laminates in which the aforementioned three-component composition is optionally used between two similar or dissimilar substrates comprising a primer between the polyethylene blend and each substrate. The resulting composite or laminate can be molded into products such as food packaging, which have good barrier properties, ie, the packaging is generally impermeable to liquids and gases. The invention also relates to films produced from the novel compositions, in particular by casting or blown film techniques.

It is therefore an object of the present invention to provide a novel composition comprising a blend of at least linear low density polyethylene, high density polyethylene and low density polyethylene.

Another object of the present invention is to provide an improved extrusion coating method for use as an extrusion coating, the novel composition comprising the blend of the invention as defined herein.

It is a further object of the present invention to provide coating substrates or composites in which the coating composition comprises the novel blends of the present invention as defined herein.

Another further object of the present invention is to provide a coating substrate or composite wherein the coating composition comprising the novel blend of the invention is applied onto the substrate by an extrusion coating method.

These and other objects and advantages of the present invention will be apparent to those skilled in the art from the following detailed description, preferred embodiments, specific examples and claims.

The present invention relates to a composition comprising a blend of at least three polyethylene components, particularly useful for extrusion coating, to an extrusion coating method using the blend and to composites made therefrom. The invention also relates to a film made from the blend.

1 and 2 are obtained using differential scanning calorimetry (DSC) to determine the melting point profile, in particular the maximum melting point and the thermal energy per unit mass required for melting of the mass. Melting point profiles and associated calorimetric data of conventional two-component blends are shown in FIG. 1. Melting point profiles and associated calorimetric data of the three component blends of the present invention are shown in FIG. 2.

The novel composition of the present invention comprises a blend of linear low density polyethylene, high density polyethylene and low density polyethylene.

Blends of linear low density polyethylene are generally known to provide heat seal strength, toughness, tear resistance and puncture resistance properties to extrusion coatings. The linear low density polyethylene component of the composition is a low density polyethylene copolymer comprising ethylene and a C ₃ -C ₁₀ alpha-olefin comonomer. The alpha-olefin comonomers are preferably C ₆ -C ₈ alpha-olefins, more preferably ethylene-hexene or ethylene-octene copolymers. The alpha-olefin comonomer is present in an amount of about 5 to about 12 weight percent, more preferably 7 to about 10 weight percent of the ethylene-alpha olefin copolymer. The ethylene-alpha olefin copolymer component is about 0.5 dg / min to about 10 dg / min, more preferably about 1 dg / min to about 3 dg / min and most preferably about 2 dg / min as measured at 190 ° C. Melt index value of; Swelling ratio of about 1.0 to about 1.2; Annealed density of about 0.90 g / cc to about 0.93 g / cc; And having a polydispersity index of about 1 to about 4. Ethylene-alpha olefin linear low density copolymers can be prepared by methods known in the art, for example as described in US Pat. No. 4,339,507.

The linear low density ethylene copolymer component of the blend of the present invention is present in an amount of about 25 to about 40 weight percent, more preferably about 30 to about 35 weight percent, most preferably about 33 weight percent based on the weight of the blend. do.

The high density polyethylene components of the blends are generally known to provide tensile strength and stress crack resistance to the blends of the present invention. The high density polyethylene component of the novel composition is a homopolymer of ethylene or a copolymer of ethylene and an alpha olefin comonomer. Alpha olefin comonomers have from about 3 to about 10 carbon atoms. The alpha olefin comonomer is present in an amount of about 0.2 to about 1 weight percent, more preferably about 0.4 to about 0.7 weight percent, even more preferably about 0.5 weight percent of the copolymer. Preferred comonomer is hexene. The high density polyethylene component may have an annealing density of about 0.940 g / cc to about 0.97 g / cc, more preferably about 0.95 to about 0.97 g / cc; And a melt index of about 6 dg / min to about 20 dg / min, more preferably about 14 dg / min to about 18 dg / min and most preferably about 16 dg / min as measured at 190 ° C. It is characterized by. The high density polyethylene component can be prepared by methods known in the art, for example as described in US Pat. No. 4,339,507.

The high density polyethylene component of the blends of the present invention is present in an amount of about 25 to about 40 weight percent, more preferably about 30 to about 35 weight percent, most preferably about 33 weight percent, based on the weight of the blend.

The low density polyethylene component of the blends of the present invention generally provide good wetting of the substrate to allow good bonding with the substrate. The low density polyethylene component of the novel compositions is a broad molecular weight distribution of polyethylene that has been shown to have a polydispersity index of about 9 to about 12. The low density polyethylene is about 3 dg / min to about 40 dg / min, more preferably about 6 dg / min to about 30 dg / min, even more preferably about 18 dg / min to about 22 dg as measured at 190 ° C. It is further characterized by having a melt index of / min, most preferably about 20 dg / min. Low density polyethylene is further characterized as having an annealing density of 0.90 g / cc to about 0.93 g / cc.

The low density polyethylene component of the blends of the present invention is present in an amount of about 25 to about 40 weight percent, more preferably 30 to about 35 weight percent, most preferably about 33 weight percent, based on the weight of the blend.

The novel compositions of the present invention can be prepared using methods known in the art. For example, the compositions can be prepared by dry blending or tumbling in conventional apparatus or by mixing in conventional mixing apparatus such as single and twin screw extruders, Werner Pfleiderer mixers, Banbury mixers and the like. have.

As will be apparent later, it has been found that less power is required to extrude the compositions of the present invention than conventional blends. This is very unexpected because the novel composition of the present invention requires a greater amount of thermal energy to melt than is needed to melt conventional blends.

The substrate to which the blend of the present invention is applied is preferably a base substrate. The primer is preferably a water soluble primer. More preferably, the substrate may be polyethyleneimine. After coating, the surface is extrusion coated with the blend. Polyethylenimines used to coat the various substrates extruded with the blends of the present invention are most preferably A-131-X polyethyleneimine primers from MICA Corporation. Extrusion coating methods are known in the art. Those skilled in the art can easily extrusion coat or extrude the compositions of the present invention onto uncoated or uncoated surfaces to make composites or laminates.

The composition of the present invention may be extrusion coated onto a substrate or extrusion laminated between two substrates. Extrusion coating and laminating means and methods are known in the art, and any of these methods is expected to be used in the present invention. It is also possible to extrude the novel composition to at least one structure of the substrate. The lamination method may further comprise the step of preparing a film from the composition of the present invention. For example, the film can be a cast or blown film. Those skilled in the art are familiar with the methods available in the art for making films from the blends of the present invention. There are many methods known in the art for producing films using cast or blown film techniques.

The substrate on which the blends of the present invention may be coated or laminated may be any substrate to which the polyolefin is typically coated. Examples of suitable substrates include, but are not limited to, paper or cardboard (printed or unprinted), coated, for example clay-coated or uncoated metal foil, plastic films, and the like. Such a surface may or may not be undersized, and preferably the surface is undersized.

The laminate according to the invention comprises two substrates, each of which may or may not be independently at the surface opposite the other substrate, and the composition of the invention is between the substrates. In such laminates, the substrates may or may not be similar. For example, the substrates may be both paper or one substrate may be paper and the other substrate may be a polymeric film.

The skilled person can determine the optimal conditions for coating or lamination without difficulty.

Films can be prepared from the novel compositions of the present invention by known methods. Preferred herein are cast and blown films, both of which are known in the art.

The compositions of the present invention may contain additional components such as additional polyethylene components, fillers, slips, tackifiers, pigments and the like, as known in the art, as long as they do not adversely affect the composition.

The invention will be more readily understood with reference to the following examples. Of course, many other forms of the invention will be apparent to those skilled in the art once the invention has been disclosed in its entirety, and therefore these examples are given for illustrative purposes only and are intended to limit the scope of the invention in any case. It should not be interpreted.

In the following examples, the test procedures shown below were used to evaluate the analytical properties of the polyethylene herein and to evaluate the physical properties of the compositions of the examples.

Melt index (dg / min) was measured according to ASTM D1238-62T at 190 ° C (374 ° F).

Flattening ratio is defined in ASTM D1238-62T as the ratio of extrudate to the pore diameter of the extruded plasticizer. When the specimen emerges from the extruded plasticizer, the diameter of the specimen is measured in the region between 0.159 cm and 0.952 cm at the beginning of the specimen. The measurement was performed by a standard method according to ASTM D374.

Annealing density (g / cc) was measured according to ASTM D1505.

The polydispersity index is the ratio of the weight average molecular weight (M _w ) and the number average molecular weight (M _n ). M _w and M _n were obtained by size-exclusion chromatography on a Waters 150C gel permeation chromatograph equipped with a standard refraction detector and a Viscotek 150R differential viscometer system. The three-column set consisted of Waters 10 ³ , 10 ⁴ , and linear-mixed layers (10 ³ , 10 ⁴ and 10 ⁵ ) Micro-Styragel HT columns. Samples were run at 140 ° C. as 0.125 weight to volume solutions in ortho-dichlorobenzene. Data was interpreted using Viscotek Unical software by general metrology using NBS 1475 (linear polyethylene) and NBS 1476 (branched polyethylene) for polyethylene samples.

Differential scanning calorimeter maximum melting point (° C.) and thermal energy (J / g) required to melt a polyolefin of a given mass were measured according to ASTM D3418.

The width W of the extruded coating was first measured on a substrate and then the neck-in (in / edge or cm / edge) was determined by subtracting the measurement from the width D of the extrusion coated die. The difference (D-W) was then divided by two, i.e. (D-W) / 2, to obtain the amount of extrudate neck-in per edge.

Ultimate heat seal strength (g _f ) was measured in a Theller Model HT tack heat seal as described in US Pat. No. 5,331,858.

Fracture tensile strength and yield tensile strength, both tensile (expressed in lb / in ² (or MPa)); And elongation at break (expressed in%) were measured according to ASTM D882.

Tear strength (g _f or mN) was measured according to ASTM D1992A.

Dart impact resistance (g at 50% failure) was measured according to ASTM D1709A.

Perforation resistance (lb / mil) was measured according to ASTM D4649.

Stress cracking (time at 50% failure (F ₅₀ )) was measured according to ASTM D1693-94.

Example 1 (comparative)

In this example, the composition used is a Dowex from Dow Chemical Company, which is thought to be a blend of 80 wt% ethylene-octene copolymer containing about 7 to about 10 wt% octene and about 20 wt% low density polyethylene. 3010 polyethylene. The blend also has a melt index of 5.8 dg / min and annealing density of 0.922 g / cc at 190 ° C.

Pellets of the Dowrex 3010 blend were tested using differential scanning calorimetry to determine the melting point profile, particularly the maximum melting point and thermal energy per unit mass required to melt the mass. Melting point profiles and calorimetric data obtained for the Dowex 3010 blend are shown in FIG. 1.

The Dowrex 3010 blend was extruded onto 40 lb of natural kraft paper by extrusion coating, a method well known in the art. Dowrex 3010 blends were 601 ° F (317 ° C) from a 3.5 in diameter extruder with its barrel heater set at 397 ° F (203 ° C), 500 ° F (260 ° C), 600 ° F (315 ° C) and 645 ° F (340 ° C). Was applied to kraft paper at a melting temperature of. The extrusion die processing rate was kept constant at a die width of 10 lb / in / hour (1.8 kg / cm / hour). Table 1 shows the extruder power (measured in% motor load and kilowatts) required to extrude the Dowrex 3010 blend at a constant extruder throughput rate. In addition, the maximum melting point of the Dowex 3010 blend as well as the energy required to melt the Dowex 3010 blend of a given mass are shown in Table 1.

Example 2

The composition of the present invention was prepared by dry blending the following ingredients:

(a) 33% by weight of Eastman Chemical Company's CM 27057-F linear low density polyethylene (melt index of about 2.0 dg / min at 190 ° C., about 0.910 g / cc by weight of the composition) Ethylene-hexene copolymers containing about 8% by weight of hexene having a density, a swelling ratio of about 1.2 and a polydispersity index of about 3);

(b) 33% by weight of Eastman Chemical Company's HT 7011-X high density polyethylene (with a melt index of about 16 dg / min and an annealing density of about 0.96 g / cc at 190 ° C.) Ethylene-hexene copolymers containing% by weight of hexene); And

(c) 33% by weight of Eastman Chemical Company's 811A low density polyethylene (having a melt index of about 20 dg / min at 190 ° C., an annealing density of about 0.92 g / cc, based on the weight of the composition, and a polydispersity of about 10) Polyethylene homopolymers) characterized by a broad molecular weight distribution expressed as an index.

The resulting three component blend, which is an example of a composition of the present invention, is characterized by having a melt index of about 5.5 dg / min and an annealing density of about 0.922 g / cc.

The pellets of the compositions of this example were tested using differential scanning calorimetry to determine the melting point profile, in particular the maximum melting point of the blend and the thermal energy per unit mass required to melt the mass. Melting point profiles and calorific data of the blends of this example are shown in FIG. 2.

The resulting blend of this example was extruded onto 40 lb of natural kraft paper. The blend was melted at 596 ° F. (313 ° C.) from a 3.5 inch diameter extruder with its barrel heater set at 398 ° F. (203 ° C.), 499 ° F. (259 ° C.), 600 ° F. (315 ° C.) and 639 ° F. (338 ° C.). It was applied to kraft paper at a temperature. The extrusion screw was single-actuated with a compression ratio of 3.5: 1 to provide uniform production through the die. The extrusion die processing rate was kept constant at a die width of 10 lb / in / hour (1.8 kg / cm / hour). Table 1 shows the extruder power (measured in% motor load and kilowatts) required to extrude the blend of Example 2, which appears at a constant extruder throughput rate. In addition, the energy required to melt the blend of Example 2 of a given mass as well as the maximum melting point of the blend is shown in Table 1.

characteristic Characteristic unit Blend of Example 1 Blend of Example 2 Motor load % 87 76 Drive motor power kilowatt 16.0 14.0 Energy required for melting J / g 79.7 93.56 Max melting point of pellet ℃ 123.01 128.28

From the data of Table 1, the following matters can be observed. The novel composition of Example 2, which is typical of the present invention, can be extruded using a lower extruder drive motor load than required for the conventional blend of Example 1. In this case, the reduction of the extruder drive motor load is 12%.

Moreover, the blend of Example 2 can be extruded using lower extruder drive motor power than required for the conventional blend of Example 1. The reduction here was 12% in the extruder drive motor power. Lowering the extruder drive motor power allows the extrusion coating operation to produce products with a greater range in power requirements before exceeding the maximum drive motor load.

The reduction in power requirements accompanying the use of the compositions of the present invention is such that the energy required to melt a given mass of the composition of Example 2 is such that the energy of Table 1 melts the mass of the blend of Example 1 (conventional blend). It is very unexpected because it indicates that it is 15% larger than required. Based on the difference in thermal energy required to melt the blends of Examples 1 and 2, with the opposite result, i.e. with the composition of the invention typical of the blend of Example 2 compared to the conventional blend of Example 1 More power requirements were expected.

Example 3 (Comparative)

In this example, the same composition as in Example 1 was used, a Dowrex 3010 blend of Dow Chemical Company. The Dowrex 3010 blend was extruded onto 40 lb of natural kraft paper. Dowrex 3010 blends were 601 ° F (317 ° C) from a 3.5 in diameter extruder with its barrel heater set at 397 ° F (203 ° C), 500 ° F (260 ° C), 600 ° F (315 ° C) and 645 ° F (340 ° C). Was applied to kraft paper at a melting temperature of. The extrusion die processing rate was kept constant at a die width of 10 lb / in / hour (1.8 kg / cm / hour). The die to nip air gap was 5.25 in (6.4 cm). Samples of coated kraft paper were obtained at 600 fpm (185 m / min) and 1000 fpm (305 m / min), and neck-in measurements of conventional Dowex 3010 blend coatings were performed at each speed. The results are reported in Table 2.

Example 4

The same composition as described in Example 2 was extruded onto 40 lb of natural kraft paper. The composition was melted at 596 ° F. (313 ° C.) from a 3.5 inch diameter extruder with its barrel heater set at 398 ° F. (203 ° C.), 499 ° F. (259 ° C.), 600 ° F. (315 ° C.) and 639 ° F. (338 ° C.). The temperature was applied to natural kraft paper. The extrusion die processing rate was kept constant at a die width of 10 lb / in / hour (1.8 kg / cm / hour). The die to nip air gap was 5.25 in (6.4 cm). Samples of coated kraft paper were obtained at 600 fpm (185 m / min) and 1000 fpm (305 m / min) and neck-in measurements of the blend coating of Example 2 (typical of the invention) were made at each speed. Was performed. The results are reported in Table 2.

characteristic Characteristic unit Blend of Example 3 Blend of Example 4 Neck-in at 600 fpm in (cm) / edge 2.55 (6.50) 2.40 (6.10) Neck-in at 1000 fpm in (cm) / edge 2.50 (6.35) 2.30 (5.85)

Examining the data in Table 2 shows the following: The composition of the present invention, typical of Example 4, gives a lower, and therefore superior neck-in value when compared to the conventional blend of Example 3. Lower neck-in values increase the extrusion coverage and reduce the edge beads of the melt extrudate. Edge beads are typically broken up and removed as waste resulting in economic losses. Thus, the composition of the present invention is characterized by low neck-in and reduced edge beads, thus reducing economic losses due to the reduced amount of removal as edge bead waste as compared to the use of the conventional blend of Example 3. Let's do it.

Example 5

Melting the same composition as Example 1 herein, ie Dow Chemical Campana's Dowrex 3010 blend at 603 ° F. (318 ° C.) at a haul-off rate sufficient to achieve a film thickness of 0.001 in (0.0254 mm). The film was cast by known techniques at temperature. The resulting cast film is heat seal strength (film to film); Tensile property; Tear resistance; Resistance to missiles, darts or shocks; And puncture resistance. The pellets of the Dowrex 3010 blend were also pressed into sheets and tested for stress cracking resistance. The results are reported in Table 3.

According to the procedure mentioned previously, the composition of Example 2 was molded at a melt temperature of 603 ° F. (318 ° C.) at a hole-off speed sufficient to obtain a film thickness of 0.001 in (0.0254 mm) to make a cast film. The resulting cast film is heat seal strength (film to film); Tensile property; Tear resistance; Resistance to missiles, darts or shocks; And puncture resistance. The pellets of the composition of Example 2 were pressed into sheets and tested for stress cracking resistance. The properties are reported in Table 3.

characteristic Characteristic unit Blend of Example 1 Blend of Example 2 Tensile Strength at Break (Machine Direction) lb / in ² (kPa) 4230-5170 (29200-35600) 4032-4928 (27600-34000) Yield Tensile Strength (Machine Direction) lb / in ² (kPa) 1764-2156 (12400-14900) 2385-2915 (16500-21000) Elongation (Machine Direction) % 689-761 599-661 Tensile Strength at Break (Transverse) lb / in ² (kPa) 3150-3850 (21800-26600) 2625-3209 (18100-22100) Yield Tensile Strength (lateral) lb / in ² (kPa) 1013-1237 (7000-8500) 1738-2124 (11900-14600) Elongation (lateral) % 836-924 836-927 Tear strength (machine direction) g 82-100 83-93 Tear strength (lateral direction) g 547-667 642-784 Dart impact resistance G at 26 in (63 cm) 46-68 36-54 Puncture resistance lb / mil (N / cm ² ) 4.04-5.46 (367-484) 4.26-5.76 (378-510) Stress cracking resistance Hour (F ₅₀ ) > 312 > 312 Extreme heat sealing strength g _f 520 510

Examining the data in Table 3 shows that the film / coating properties obtained when using the novel compositions of the present invention are substantially similar to those obtained when using the conventional blend of Example 1.

Example 6

Blown films were prepared using the composition of Example 2. Methods of making blown films are known in the art. More specifically, the composition of Example 2 was extruded from a 2.5 in. (6.4 cm) diameter extruder equipped with five heating zones and having a length to diameter ratio of 24: 1. The annular extrusion die had a diameter of 6 in (15.3 cm) and the land to land separation of the die was set uniformly to 0.088 in (0.224 mm). The extrudate temperature was 385 ° F. (196 ° C.). The extrudate production rate was 89 lb / hr (41 kg / hr) and the blow-off speed of the blown film was 78 fpm (24 m / min). The film blowing ratio was 2.5, resulting in a tubular flat width of 22.5 in (57 cm). The resulting film blown out of the composition of Example 2 was uniform in thickness and had excellent overall quality.

From all of the above, it is clear that the novel compositions of the present invention have many uses. For example, the novel compositions can be molded into cast and blown films using well known techniques for forming cast and blown films. In addition, the novel compositions of the present invention have substantially the same film / coating properties as conventional compositions, while having improved processing properties, ie, low extruder motor drive power requirements and low neck-in, ie, low edge beads. It can be used to prepare.

While the invention has been described above in detail with specific reference to its preferred embodiments, it will be appreciated that modifications and variations other than those specifically described herein may be carried out within the spirit and scope of the invention.

Claims (10)

(a) the alpha olefin comonomer is present in an amount of 5 to 12% by weight based on the weight of the first copolymer and the first ethylene alpha-olefin copolymer has a melt index of 0.5 to 10 dg / min at 190 ° C., 25-40% by weight of ethylene and C ₃ -C ₁₀ alpha based on the weight of the composition, having a swelling ratio of 1.0 to 1.2, annealing density of 0.90 to 0.93 g / cc, and a polydispersity index of 1 to 4. A first copolymer of olefin comonomers; (b) the alpha olefin comonomer is present in an amount of 0.2 to 1% by weight based on the weight of the second ethylene-alpha olefin copolymer and the first homopolymer and the second ethylene-alpha olefin copolymer of ethylene are 0.940 to A first homopolymer of ethylene or C ₃ -C ₁₀ alpha of 25 to 40% by weight, based on the weight of the composition, having an annealing density of 0.97 g / cc and a melt index of 6 to 20 dg / min at 190 ° C. A second copolymer of olefin comonomers; And (c) 25 to 40 weight percent of ethylene, based on the weight of the composition, having a polydispersity index of 9 to 12, a melt index of 3 to 40 dg / min at 190 ° C., and an annealing density of 0.90 to 0.93 g / cc. Second homopolymer Polymer blend composition comprising a. The method of claim 1, A composition wherein the alpha olefin comonomer of the first ethylene-alpha olefin copolymer has 6 to 8 carbon atoms and the first ethylene-alpha olefin copolymer has a melt index of 1 to 3 dg / min at 190 ° C. The method of claim 1, Wherein the first homopolymer and the second ethylene-alpha olefin copolymer of ethylene have an annealing density of 0.95 to 0.97 g / cc and a melt index of 14 to 18 dg / min at 190 ° C. The method of claim 1, Wherein the second homopolymer of ethylene has a melt index of 18 to 22 dg / min at 190 ° C. The method of claim 1, Wherein each of (a), (b) and (c) is present in an amount of 30 to 35 weight percent based on the weight of the composition. A method comprising extrusion coating a composition according to claim 1 onto a substrate. An article comprising a substrate and a coating comprising a composition according to claim 1. The method of claim 7, wherein An article made by extrusion coating the composition of claim 1 onto a substrate. Film formed from the composition according to claim 1. An article made from the composition according to claim 1 wherein the film is a component of a multiple laminate structure.