JPH0259768B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a laminated film based on poly-4-methyl-1-pentene having excellent heat-sealability. [Prior art] Poly-4-methyl-1-pentene is known for its transparency,
Taking advantage of its heat resistance and chemical resistance, it is used for chemical experiment equipment such as beakers and graduated cylinders, syringes for syringes, optical measurement cells, microwave oven trays, and baking cartons by coating paper. However, while poly-4-methyl-1-pentene has a high melting point and good heat resistance,
It has the disadvantage of poor heat sealability.
As a method for improving heat sealability, polyethylene, polypropylene, etc., poly(4-methyl-1-
The most common method is to bond poly-4-methyl-1-pentene with a resin that has a lower melting point than pentene and has excellent heat-sealability.
Although pentene is a polyolefin, it has poor adhesive properties and cannot be put to practical use simply by laminating it.Also, polyethylene is produced by applying a urethane adhesive or the like as an anchor coating agent to poly4-methyl-1-pentene film. Even when films and the like are laminated, poly-4-methyl-1-pentene film has poor surface wettability, the adhesive strength of the laminated film is low, and the heat-sealability is not improved as much. [Problems to be Solved by the Invention] In view of this situation, the present inventor conducted various studies to improve the heat-sealability of poly-4-methyl-1-pentene film, and as a result, developed poly-4-methyl-1-pentene film.
- When laminating pentene film and polyethylene film or polypropylene film,
It was found that by using a specific propylene/α-olefin random copolymer as the adhesive layer, adhesive strength was improved and a laminated film with excellent heat sealability could be obtained.
It was filed as 1387. After further consideration,
It was found that the adhesive strength was further improved by using a composition prepared by adding and mixing poly4-methyl-1-pentene to the propylene/α-olefin random copolymer for the adhesive layer, and the present invention was achieved based on this finding. [Means for solving the problem] That is, the present invention provides a poly-4-methyl-1-pentene (A) layer with a propylene content on at least one side.
50 to 87 mol% and differential scanning calorimetry (DSC)
The heat of crystal fusion is 10 or more based on thermal analysis of
80 Joule/g of propylene/α-olefin random copolymer (B) 95 to 40% by weight and poly4-methyl-1-pentene (A ₂ ) 5 to 60% by weight through the composition (C) layer. Polyolefin (D) whose main component is α-olefin having 2 to 4 carbon atoms.
The object of the present invention is to provide a laminated film with excellent heat-sealability, which is characterized by being formed by laminating layers. [Function] Poly-4-methyl-1-pentene used in the present invention
(A) and poly-4-methyl-1-pentene (A ₂ ) are homopolymers of 4-methyl-1-pentene or 4-methyl-1-pentene and other α-olefins, such as ethylene, propylene, -butene,
1-hexene, 1-octene, 1-decene, 1-
Copolymer with α-olefin having 2 to 20 carbon atoms such as tetradecene and 1-octadecene, usually 4-
It is a polymer mainly composed of 4-methyl-1-pentene, which contains 85 mol% or more of methyl-1-pentene.
The melt flow rate (MFR ₅ , load: 5Kg, temperature: 260°C) of poly4-methyl-1-pentene (A) and poly4-methyl-1-pentene (A ₂ ) is preferably 0.5 to 200g/10min. It's a range of things. Those with a melt flow rate of less than 0.5 g/10 min have high melt viscosity and poor moldability, and those with a melt flow rate of more than 200 g/10 min have low melt viscosity and poor moldability, and also have low mechanical strength. In addition, in the present invention, poly4-methyl-1-pentene (A) and poly4-methyl-1-pentene (A ₂ )
may be the same or different as long as they are within the above range. The propylene/α-olefin copolymer (B) used in the present invention has a propylene content of 50 to 87 mol%, preferably 60 to 80 mol%, and crystals based on thermal analysis using a differential scanning calorimeter (DSC). Heat of fusion is 10 to 80 Joule/g, preferably 20 to 80 Joule/g
70 Joule/g, preferably melt flow rate (MFR ₂ :ASTM D 1238, L)
0.5 to 200g/10min, more preferably 2 to 50g/10min, preferably melting point 90 to 130
℃, more preferably in the range of 105 to 125℃. If the propylene content exceeds 87 mol% or the heat of crystal fusion exceeds 80 Joule/g, they will have poor adhesion to the poly4-methyl-1-pentene (A), and will not be laminated with the polyolefin (D) described below. However, the heat sealability is not improved. On the other hand, if the propylene content is 50 mol% or the heat of crystal fusion is
Those with less than 10 Joule/g have adhesive properties, but
Since the adhesive strength is weak and the heat resistance is also poor, the effect of improving heat sealability is small, and there is a risk that the heat resistance, which is an inherent characteristic of poly-4-methyl-1-pentene, may be impaired, which is not preferable. Furthermore, those with MFR outside the above range may have poor moldability, and those with melting points outside the above range also tend to have poor adhesiveness. In addition to the above properties, the propylene/α-olefin random copolymer (B) used in the present invention also has the following properties:
The microisotacticity (hereinafter abbreviated as MIT) of three propylene chains is 0.7 or more, and
0.8 or more and boiling n-heptane insoluble content is 5% by weight
Preferably, the content is preferably 3% by weight or less.
If a film with an MIT of less than 0.7 is used, low molecular weight substances may bleed out to the film interface after aging, reducing adhesive strength. This is because the amount of block-polymerized components is large, and when such a copolymer is used, the effect of improving adhesion may be small. In the random copolymer (B), the α-olefin copolymerized with propylene is usually an α-olefin having 2 to 20 carbon atoms excluding propylene, and specifically, for example, ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene,
1-octene, 1-decene, 1-tetradecene,
Examples include 1-octadecene. Among these, those having 4 to 10 carbon atoms are particularly preferred. The heat of fusion of the random copolymer (B) in the present invention is measured by measuring the specific heat curve of the copolymer in a completely molten state (preferably the specific heat curve shown at 160°C or higher and 240°C or lower) using a differential scanning calorimeter. This is a value calculated using a straight line obtained by direct extrapolation to the low temperature side as the baseline. The heat of fusion and melting point are measured under the following measurement conditions. That is, after leaving the sample at 200℃ for 5 minutes,
Cool down to -40℃ at a rate of ℃/min, and cool down to -40℃ for 5 minutes.
Leave for a minute. After that, at a heating rate of 20℃/min -
Measurements are taken from 40℃ to 200℃. Microisotacticity is a value determined by focusing on three propylene chains using ¹³ C nuclear magnetic resonance spectroscopy and quantifying the fraction in which three propylene chains are arranged in an isotactic manner. The amount of boiling n-heptane insoluble matter is determined by the following method. That is, a small sample of approximately 1 mm x 1 mm x 1 mm and glass beads are placed in a cylindrical glass filter (G3) and extracted using a Soxhlet extractor.
Extract for 14 hours. In this case, the reflux frequency is approximately once/5 minutes. The weight percent of insoluble matter is determined by weighing the molten part or insoluble matter. Propylene content with the above properties
The 50 to 87 mol% propylene/α-olefin random copolymer (B) is, for example, (a) a composite containing at least magnesium, titanium, and halogen, (b) a metal from Group 1 to Group 3 of the periodic table. It is obtained by random copolymerization of propylene and α-olefin using a catalyst formed from an organometallic compound and (c) an electron donor. Part or all of the electron donor (c) may be immobilized on part or all of the complex (a), or may be brought into preliminary contact with the organometallic compound (b) prior to use. Good too. Particularly preferred is an embodiment in which a part of the electron donor (c) is immobilized on the complex (a), and the remainder is added to the polymerization system as it is or is used after being brought into preliminary contact with the organometallic compound (b). be. In this case, the electron donor immobilized on the complex (a) and the electron donor used by directly adding it to the polymerization system or by pre-contacting it with (b) may be the same or different. It's okay. The composition (C) layer used in the present invention is the propylene
α-olefin random copolymer (B) 95 to 40% by weight, preferably 90 to 50% by weight and the poly(4)
-Methyl-1-pentene ( _A2 ) 5 to 60% by weight, preferably 10 to 50% by weight. If the amount of poly4-methyl-1-pentene (A ₂ ) is less than 5% by weight, the adhesive strength will not be improved much, while if it exceeds 60% by weight, the adhesive strength with the polyolefin (D) layer described below will decrease. Heat seal strength is not improved. The polyolefin (D) used in the present invention refers to a polyolefin whose main component is α-olefin having 2 to 4 carbon atoms, that is, ethylene, propylene, 1
- It is a crystalline polymer whose main component is butene.
Specifically, these polyolefins include polyethylene (E), polypropylene (F), and poly-1-butene.
(G), but all of these are not limited to homopolymers, as long as these olefins are the main component, other α-olefins having 2 to 20 carbon atoms, vinyl acetate, vinyl chloride, acrylic acid, meth It also includes copolymers with vinyl compounds such as acrylic acid and styrene, and also graft copolymers graft-modified with unsaturated carboxylic acids such as maleic anhydride, maleic acid, and acrylic acid, or their derivatives. But that's fine. Further, these polyolefins (D) may be a mixture. Specific examples of the polyethylene (E) include high-pressure low density polyethylene (so-called LDPE), ethylene-propylene copolymer, ethylene-1-butene copolymer, and ethylene-4-methyl-1-pentene copolymer. , ethylene-1-hexene copolymer,
High-density polyethylene (so-called HDPE), ethylene
Examples include vinyl acetate copolymers and ethylene-acrylic acid copolymers. Among these, LDPE,
Ethylene/α-olefin copolymer, ethylene/
Vinyl acetate copolymers are preferred because they have excellent transparency and low-temperature heat-sealing properties.
0.910 to 0.960 and melting point (T _n :ASTM D
3418) is preferably in the range of 100 to 135°C. The melt flow rate (MFR ₃ : ASTM D 1238, E) of polyethylene (E) is not particularly limited, but is usually 0.01 to 30 from the viewpoint of moldability.
g/10 min, preferably in the range of 0.1 to 10 g/10 min. Specific examples of the polypropylene (F) include polypropylene (propylene homopolymer),
Propylene random copolymers such as propylene/ethylene random copolymer, propylene/ethylene/1-butene random copolymer, and propylene/1-butene random copolymer (propylene content usually 90 mol% or more, preferably 95 mol%) above), propylene/ethylene block copolymers (ethylene content usually 5 to 30 mol%), and the like. Among these, homopolymers and random copolymers are preferred because they have excellent transparency.
In particular, a random copolymer having a melting point (Tm: ASTM D 3418) of 130 to 140°C is preferable because it has excellent heat sealability. Furthermore, polypropylene (F)
MFR ₂ is not particularly limited, but from the point of view of formability, it is usually 0.5 to 30g/10min, and even 0.5 to 30g/10min.
A range of 10g/10min is preferable. Specific examples of the poly-1-butene (G) include 1-butene homopolymer, 1-butene/ethylene copolymer, 1-butene/propylene copolymer,
-butene/4-methyl-1-pentene copolymer. The melt flow rate (MFR ₃ : ASTM D 1238, E) of poly-1-butene (G) is not particularly limited, but from the viewpoint of moldability it is usually 0.01 to 100 g/10 min, and more preferably 0.03 to 30 g/10 min.
A range of 10 min is preferable. The laminated film of the present invention includes the propylene/α-olefin random copolymer (B) and poly4-methyl-1-pentene (A ₂ ) on at least one side of the poly4-methyl-1-pentene (A) layer. This is a laminated film formed by laminating the above polyolefin (D) layer via a composition (C) layer with ). The laminated film of the present invention can be produced by various known methods, such as a method in which a poly4-methyl-1-pentene (A) film is formed in advance and then extrusion coated with the composition (C) and the polyolefin (D); A method in which a poly4-methyl-1-pentene (A) film is preformed and then a separately molded polyolefin (D) film is extrusion laminated using the composition (C), or a poly4-methyl-1-pentene (A) film is extrusion laminated using the composition (C). ), composition (C)
and polyolefin (D) using a multilayer die having a multilayer structure having at least three layers, composition (C)
Examples include a method of coextrusion molding using the intermediate layer as an intermediate layer, but coextrusion molding is preferred because it is easy to operate and can provide a laminated film with better interlayer adhesion. As a coextrusion molding method, flat
There are a T-die method using a die and an inflation method using a circular die. Flat
The die is a single die using black box.
Either a manifold type or a multi-manifold type may be used. Any known die can be used for the die used in the inflation method. The thickness of each layer of the laminated film of the present invention is not particularly limited, but the poly4-methyl-1-pentene (A) layer is usually 10 to 100μ, preferably 10 to 50μ, and the composition (C) layer is usually 10 to 100μ. 5 to 50μ, preferably 10 to 30μ, usually the heat seal layer of polyolefin (D) ranges from 10 to 100μ, preferably 10 to 50μ. The laminated film of the present invention is poly4-methyl-1
-Pentene (A) layer/Composition (C) layer/Polyolefin (D)
As long as the layer is a constituent requirement, there are no particular limitations,
A heat-sealing layer of polyolefin (D) may be laminated on both sides of the poly-4-methyl-1-pentene (A) layer via a composition (C) layer. For application, polyvinylidene chloride resin, polyvinyl alcohol, saponified ethylene/vinyl acetate copolymer, polyamide, polyester, paper, aluminum foil, etc. may be laminated. A weathering stabilizer, The purpose of the present invention is to use various compounding agents that are usually added to polyolefins, such as heat-resistant stabilizers, antistatic agents, antifogging agents, antiblocking agents, slip agents, lubricants, pigments, dyes, droplet agents, and nucleating agents. may be added to the polyolefin (D) layer that becomes the heat-sealing layer, in order to further improve the heat-sealability, a low-crystalline or amorphous ethylene-propylene copolymer may be added to the polyolefin (D) layer that will become the heat-sealing layer. , ethylene/α- such as ethylene/1-butene copolymer
Olefin copolymers, ethylene/vinyl acetate copolymers, etc. may be added. [Effects of the Invention] The laminated film of the present invention is made of poly4-methyl-1-
It has the heat resistance, transparency, surface gloss, water repellency, etc. of pentene, and has improved heat-sealability, so it can be used to make use of its properties to be used in various foods (e.g. vegetables, confectionery, meat), breads, and marine products. It is suitable as a packaging material for etc. [Examples] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded. Example 1 4-methyl-1-penten-1-decene copolymer (hereinafter abbreviated as TPX-) with density: 0.835 g/cm ³ and MFR ₅ : 26 g/10 min, propylene content:
71.0 mol%, heat of crystal fusion: 50 Joule/g, melting point: 110°C, MFR ₂ : 7.0 g/10 min, boiling n-heptane insoluble content: 0.5%, boiling methyl acetate soluble content:
Composition consisting of 70% by weight of propylene/1-butene random copolymer (hereinafter abbreviated as PBR-) of 0.5% and MIT: 0.94 and 30% by weight of TPX-
and density: 0.917g/cm ³ , MFR ₃ : 6.5g/
10min and Tm: 105℃ high pressure polyethylene (hereinafter abbreviated as LDPE) was used as an intermediate layer, and each was extruded using a 40mmφ extruder (cylinder temperature: 270℃).
After melting in a 40mmφ extruder (cylinder temperature: 250℃) and a 40mmφ extruder (cylinder temperature: 250℃), it was extruded through a spiral die for three-layer inflation film molding (die temperature: 260℃) and cooled with water. , TPX-: 20μ, composition-: 20μ and
A coextruded three-layer film consisting of LDPE-:20μ was obtained. Next, the physical properties were evaluated by the following method. Adhesive strength (g/15mm): Cut a 15mm wide test piece and crosshead speed.
The strength is shown as the strength when peeling between each resin layer at 200 mm/min. Peel strength of heat-sealed part (g/15mm): Polyolefin layers are stacked and heat-sealed at a temperature of 120℃ and 250℃ with a pressure of 2Kg/cm ² for 1 second using a sealing bar with a width of 10mm, and then allowed to cool. 15mm from now
Cut a width specimen and crosshead speed 200
It is expressed as the strength when the heat-sealed part is peeled off in mm/min. The results are shown in Table 1. Example 2 Instead of the intermediate layer composition of Example 1
The same procedure as in Example 1 was carried out except that a composition consisting of 50% by weight of PBR and 50% by weight of TPX was used. The results are shown in Table 1. Example 3 Instead of LDPE in Example 1, density: 0.91
g/cm ³ , MFR: 5g/10min and Tm: 140℃ propylene-ethylene random copolymer (hereinafter
The same procedure as in Example 1 was conducted except that PP- (abbreviated as PP-) was used and the cylinder temperature of the PP- extruder was set at 270°C. The results are shown in Table 1. Example 4 Instead of PBR- in Example 3, propylene content: 80.5 mol%, heat of crystal fusion 61 Joule/g,
Melting point: 124℃, MFR ₂ : 3.1g/10min, boiling n-
The same procedure as in Example 3 was carried out except for using a propylene/1-butene random copolymer (PBR-) having a heptane insoluble content of 1.2%, a boiling methyl acetate soluble content of 0.4%, and an MIT of 0.97. The results are shown in Table 1. Comparative Example 1 Instead of the composition which is the intermediate layer of Example 1
The same procedure as in Example 1 was carried out except that PBR- was used. The results are shown in Table 1.

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Claims (1)

[Claims] 1 Propylene content 50 to 87 mol% on at least one side of the poly4-methyl-1-pentene (A) layer
and 95 to 40% by weight of propylene/α-olefin random copolymer (B) having a heat of crystal fusion of 10 to 80 Joule/g based on thermal analysis by differential scanning calorimeter (DSC) and poly4-methyl-1-pentene. (A ₂ ) A layer of polyolefin (D) mainly composed of α-olefin having 2 to 4 carbon atoms is laminated via a layer of composition (C) consisting of 5 to 60% by weight. laminated film.