JPH024425B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a composite film, which has particularly good film formability.
Moreover, the present invention relates to a composite film coated with a polyolefin composition having excellent heat-sealing strength and hot-tack properties. As a coating material for composite films made by extrusion coating, high-pressure polyethylene, so-called LDPE, is used in the largest amount because it has good low-temperature heat-sealability as a sealant and is excellent in processability. however
Since LDPE is inferior in heat-sealing strength, hot-tack properties, etc., attempts have been made to improve or replace LDPE. Materials that can replace LDPE include high-density polyethylene (HDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA),
Although some ionomers are used, HDPE
Although PP has excellent heat sealing strength, it has poor low temperature sealing properties, has a large net seal, and has poor processability.
has strong heat-sealing strength, but is susceptible to surging during extrusion processing, and is susceptible to thermal decomposition and a decrease in molecular weight.
There are disadvantages in processing such as a large network, EVA has excellent low-temperature sealing properties but has a unique odor, and ionomers have excellent heat-sealing strength and hot-tack properties, but they require a large load during extrusion processing. All materials have advantages and disadvantages, such as poor workability, and none of them can be said to be optimal. Therefore, the present inventors investigated a composite film having a sealant that has excellent film forming properties, heat seal strength, and hot tack properties, and as a result, they arrived at the present invention. That is, in the present invention, the base material has a melt index of 1.
or 50g/10min, density 0.910 or 0.940g/
cm ³ , melting point 115-130°C and ethylene content 94
Random copolymer (A) of 99 to 99.5 mol% of ethylene and α-olefin having 4 to 10 carbon atoms and 99 to 30% by weight of melt index 1 to 70 g/
10min high pressure polyethylene (B) 1 to 70% by weight
It is a composite film formed by extrusion coating a composition consisting of. Number of carbon atoms copolymerized with ethylene in copolymer (A): 4
Specifically, α-olefin having 6 to 10 carbon atoms is 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, or a mixture thereof. to 8 α-olefins, especially 4-methyl-1
-Pentene is preferred. Melt index (MI) of copolymer (A)
(ASTMD1238E) should be in the range of 1 to 50 g/10 min, preferably 5 to 40 g/10 min. If the MI exceeds 50g/10min, the load during extrusion coating is small, but when made into a composite film, the heat sealing strength is weak and the MI is 1.
If it is less than g/10 min, the fluidity characteristics are poor and therefore it is inferior during extrusion processing. The density of the copolymer (A) is 0.910 to 0.940 g/cm ³ ,
It should preferably be in the range of 0.915 to 0.935 g/cm ³ . If the density exceeds 0.940g/ ^cm3 , the hot-tack properties and transparency will be poor, and the density will be 0.910.
If it is less than g/cm ³ , it is not preferable because it has poor heat-sealing strength and tends to become sticky, and when used as a sealant, the film will block. The copolymer (A) has one or more points showing a sharp peak determined from an endothermic curve measured at a heating rate of 10°C/min using a differential scanning calorimeter (DSC), and the highest temperature of the peak, that is, the melting point A range of 115 to 130°C, preferably 115 to 125°C is suitable for the present invention. If the 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. The measurement of the density of the copolymer (A) in the present invention is as follows:
This is a value measured by the method of ASTMD1505, and the density of copolymer (A) largely depends on the proportion of copolymer components, and the density of copolymer (A) is 0.910 to 0.940 g/cm ³
The copolymer component is in the range of 0.5 to 6
It is necessary that the amount is in the range of mol %, preferably 1.0 to 5.0 mol %, particularly preferably 2.0 to 4.0 mol %. Copolymer (A) having the above performance used in the present invention
Examples of the catalyst for producing the above include a highly active titanium catalyst component formed from a magnesium compound and a titanium compound, such as a catalyst consisting of a titanium-based solid catalyst supported on a hydrocarbon-insoluble magnesium compound and an organoaluminium compound. . The high pressure polyethylene (B) used in the present invention is
MI is 1 to 70g/10min, preferably 3 to 25g/10min, density is preferably 0.915 to
It has a weight of 0.925g/ ^cm3 . Those with an MI of more than 70 g/10 min and those with an MI of less than 1 g/10 min are not preferred because they have poor compatibility with the copolymer (A). In addition, the high-pressure polyethylene referred to in the present invention is
Not only a homopolymer of ethylene, but also a copolymer of ethylene with a small amount of other polymerizable monomers, such as vinyl acetate, acrylic ester, etc., within a range that does not impair the purpose of the present invention, such as 20% by weight or less. It may be hot. The composition used for the composite film of the present invention has a mixing ratio (weight ratio) of the copolymer (A) and high-pressure polyethylene (B): (A)/(B) of 99/1 to 30/
70, preferably in the range of 95/5 to 70/30. If the high-pressure polyethylene (B) content is less than 1% by weight, it will cause surging in the extrusion coating, making it difficult to obtain a good composite film, and if the high-pressure polyethylene (B) content exceeds 70% by weight, edges will break during the extrusion coating. A good composite film cannot be obtained, and the heat seal strength and hot tack properties cannot be improved. In order to obtain the composite film of the present invention using the above composition, the copolymer (A) and high-pressure polyethylene (B) are mixed in the above range using, for example, a V-blender, ribbon blender, Henschel mixer, tumbler blender, etc. After that, the base material is extrusion coated with a T-die, or the mixture is further coated with an extruder,
There is a method of extrusion coating using a T-die after kneading with a kneader, a Banbury mixer, etc. and granulating the product. The composition includes weathering stabilizers, heat stabilizers, antistatic agents, antifogging agents, antiblocking agents, slip agents, lubricants, pigments, dyes, flow agents, etc., which are usually added to the polyolefin. Various compounding agents may be blended within the range that does not impair the purpose of the present invention. The base material of the composite film of the present invention may be any polymer or paper having film-forming ability,
Aluminum foil, cellophane, etc. can be used. Examples of such polymers include high density polyethylene, medium and low density polyethylene, ethylene/vinyl acetate copolymer, ethylene/acrylic acid ester copolymer, ionomer, polypropylene, poly-1-butene, poly-4 -methyl-1
- Olefin polymers such as pentene, vinyl polymers such as polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylate, polyacrylonitrile, nylon 6, nylon 66, nylon 7,
Nylon 10, Nylon 11, Nylon 12, Nylon
610, polyamides such as polymethaxylylene adipamide, polyesters such as polyethylene terephthalate, polyethylene terephthalate/isophthalate, and polybutylene terephthalate, polyvinyl alcohol, ethylene/vinyl alcohol copolymers, and polycarbonates. These base materials can be appropriately selected depending on the purpose and the item to be packaged. For example, in the case of foods that are easily packaged with corrosion, resins with excellent transparency, rigidity, and gas permeation resistance such as polyamide, polyvinylidene chloride, ethylene/vinyl alcohol copolymer, polyvinyl alcohol, and polyester are recommended. 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. In order to extrusion coat the composition used in the present invention on the base material, the base material may be directly extrusion coated, or in order to increase the adhesive strength between the base material and the composition, a known coating may be applied to the base material in advance. For example, extrusion coating may be performed after applying an organic titanium-based, polyethyleneimine-based, or isocyanate-based anchor coating material, and further underlaying an adhesive polyolefin, high-pressure polyethylene, or the like. The composite film of the present invention can be obtained even at high speeds without any thickness or thinness unevenness, so it has better productivity than conventional composite films made by extrusion coating of single high-pressure polyethylene, and has excellent hot-tackability and heat-sealing strength. Depending on the base material, it also has excellent transparency, so it can be used for various packaging bags, such as packaging bags for liquid soups, pickles, string konjac, etc.
Paste packaging bags for miso, jam, etc., powder packaging bags for sugar, flour, furikake, etc., pharmaceutical tablets,
Suitable for granule packaging bags. 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 MI: 29g/10min, density: 0.921g/cm ³ , melting point
90 parts by weight of ethylene/4-methyl-1-pentene random copolymer (abbreviated as EMP-I) at 121°C and ethylene content of 96 mol% and MI: 65 g/10 min
and 10 parts by weight of high-pressure polyethylene (abbreviated as HPPE-Ι) with a density of 0.917 g/cm ³ were mixed in a Henschel mixer, and the mixed composition was melted in a 65 mmφ extruder (set temperature: 280°C). , width 500mm T
- From a die, onto a biaxially stretched nylon film (biaxially stretched nylon layer: 15μ coated with HPPE-Ι layer: 20μ) (abbreviated as O-N _y -LAMI) on which the HPPE-Ι has been laminated in advance, As a result of extrusion coating with a thickness of 30μ, the netuquin is 51mm.
(one edge), the mixed composition did not suffer from edge breakage or film shaking (surging) up to an extrusion coating speed of 145 m/min, and a good composite film with no thickness or thinness unevenness was obtained. The composite film was then subjected to a performance test using the following method. Haze (%): ASTM D 1003 Impact strength (Kg/cm/cm): ASTM D 3420 Peel strength of heat-sealed part (g/15mm): Overlap film surfaces, 120℃, 130℃, 140℃, 150℃ ,
2 with a temperature of 170℃ and a seal bar with a width of 5mm.
After sealing for 1 second under a pressure of Kg/cm ² , the mixture was allowed to cool.
A test piece with a width of 15 mm was cut from this, and the heat-sealed portion was peeled off at a crosshead speed of 200 mm/min, and the strength at that time was defined as the peel strength. Hot tack test (mm): 550mm long x 20mm wide test pieces stacked at 130℃, 140℃, 150℃, 160℃
After sealing for ¹ second at a pressure of 2Kg/cm2 using a sealer with a width of 5mm and a length of 300mm at a temperature of 170℃,
At the same time as the pressure was removed, a load of 43 g was applied to each test piece to forcibly peel off the seal portion, and the hot-tack property was evaluated based on the peeled distance (mm). That is,
The shorter the peeling distance, the better the hot-tack properties. The results are shown in Table 1. Implementation 2 The mixing ratio of EMP-Ι and HPPE-Ι in Example 1 was
The same procedure as in Example 1 was carried out except that a mixed composition of 80 parts by weight: 20 parts by weight was used. As a result, Netsuquin is 34mm (one ear) and extrusion coating speed
No edge breakage or film wobbling occurred up to 145 m/min, and a good composite film with no thickness or thinness unevenness was obtained. The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Example 3 MI: 14g/instead of EMP- in Example 2
10min, density: 0.922g/cm ³ , melting point 121°C, ethylene content 96 mol% ethylene 4-methyl-
The same procedure as in Example 2 was carried out except that 1-pentene random copolymer (EMP-) was used. As a result, NETSUQUIN did not cause edge breakage or film shaking at extrusion coating speed of 145 m/min at 38 mm (one edge).
A good composite film with no thick or thin unevenness was obtained.
The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Example 4 MI: 7.8g/instead of EMP- in Example 1
10min, density: 0.920g/cm ³ , melting point 121°C, ethylene content 96 mol% ethylene 4-methyl-
The same procedure as in Example 1 was conducted except that 1-pentene random copolymer (EMP-) was used. As a result, NETSUQUIN did not cause edge breakage or film shaking at extrusion coating speed of 145 m/min at 38 mm (one edge).
A good composite film with no thick or thin unevenness was obtained.
The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Example 5 Instead of HPPE- used in Example 4,
The same procedure as in Example 4 was conducted except that MI: 10 g/10 min and high pressure polyethylene (HPPE-) having a density of 0.916 g/cm ³ were used. However, O-N _y -LAMI of Example 1 was used as the base film. As a result, Netsuquin has an extrusion coating speed of 38 mm (one ear)
No edge breakage or film wobbling occurred up to 145 m/min, and a good composite film with no thickness or thinness unevenness was obtained. The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Comparative Example 1 The same procedure as Example 1 was carried out except that EMP- of Example 1 was used alone instead of the mixed composition used in Example 1. As a result, Netkuin is 57~
Large size of 63mm (one ear), extrusion coating speed
No edge breakage occurred up to 145 m/min, but when the extrusion coating speed exceeded 60 m/min, film shaking occurred, and a good composite film could not be obtained at high speeds. The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Comparative Example 2 The same procedure as Comparative Example 1 was carried out except that EMP- used in Example 3 was used alone instead of EMP- used in Comparative Example 1. As a result, netquin
It was large at 71 to 74 mm (one ear), and no ear breakage occurred up to an extrusion coating speed of 145 m/min.
When the extrusion coating speed exceeded 70 m/min, film wobbling occurred, and a good composite film could not be obtained at high speeds. The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Comparative Example 3 The same procedure as Comparative Example 1 was conducted except that EMP- used in Example 4 was used alone instead of EMP- used in Comparative Example 1. As a result, netquin
It was large at 64 to 66 mm (one ear), and no ear breakage occurred up to an extrusion coating speed of 145 m/min.
When the extrusion coating speed exceeded 80 m/min, film wobbling occurred, and a good composite film could not be obtained at high speeds. The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Comparative Example 4 Instead of the mixed composition used in Example 1,
The same procedure as in Example 1 was carried out except that high-pressure polyethylene (HPPE-) having an MI of 5.1 g/10 min and a density of 0.919 g/cm ³ was used alone. As a result, NETSUIN was as small as 20 mm (one edge), and no film wobbling occurred up to an extrusion coating speed of 145 m/min, but edge breakage occurred when the extrusion coating speed exceeded 80 m/min. was not obtained. The performance of the composite film was evaluated using the method described in Example 1 below. The results are shown in Table 1. Comparative Example 5 Instead of the mixed composition used in Example 1,
The same procedure as in Example 1 was carried out except that an ethylene/vinyl acetate copolymer (EVA) having MI: 7.5 g/10 min, density: 0.924 g/cm ³ and vinyl acetate content of 6 wt% was used. As a result, the NETSUQUIN was as small as 24 mm (one ear), and no fluctuation occurred up to an extrusion coating speed of 145 m/min, but at an extrusion coating speed of 100 m/min,
When the speed exceeds m/min, edge breakage occurs, and a good composite film cannot be obtained at high speeds. Furthermore, the set temperature of the extruder was 240°C. The performance of the composite film was evaluated using the method described in Example 1 below.
The results are shown in Table 1. 【table】

Claims (1)

[Claims] 1 Melt index 1 to 50g/base material
Random copolymer (A) of ethylene and α-olefin having 4 to 10 carbon atoms with a density of 0.910 to 0.940 g/cm ³ , a melting point of 115 to 130°C and an ethylene content of 94 to 99.5 mol% (A) 99 to 30% by weight %
and 1 to 70% by weight of high-pressure polyethylene (B) having a melt index of 1 to 70 g/10 min.