JPH11235798A - Multi-layer polyolefine film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer film which is highly resistant to heat and impact and rigid, and also shows working properties as a surface material in the work to lap the surfaces of various base materials and for deep drawing or the like. SOLUTION: This multi-layer polyolefine film is formed of a resin material comprising 50-100 wt.% of crystalline polypropylene and 50-0 wt.% of an ethylene.α-olefin copolymer which has the H/W value of 2 or more when the height of a largest peak, whose temperature is 15-85 deg.C, of an eluation curve to be obtained by elution fractionation at temperatures rise is given as H and the width of the peak at a height which is one third of the height of the peak is given as W, as an outer layer and an inner layer, and a resin material formed of 0-95 wt.% of a propylene copolymer whose fusion peak by DSC is within the range of 110-165 deg.C and 100-5 wt.% of the ethylene.α-olefin copolymer with the H/W value of 2 or more, as an intermediate layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin-based multilayer film. For details, heat resistance,
The present invention relates to a polyolefin-based multilayer film having excellent rigidity and impact resistance, and further having excellent lapping workability and deep drawing workability.

[0002]

2. Description of the Related Art Polypropylene film has heat resistance,
It is excellent in rigidity, mechanical strength, transparency and gloss, and is used in various applications, for example, packaging films for food packaging, textile packaging, etc.,
Medical applications such as infusion bags, surface protective films such as decorative plywood, metal plates, painted steel plates, and synthetic resin plates, films for decorative materials, adhesive tape substrates, and surface materials such as films for construction materials in the civil engineering and construction fields. Used in a variety of functional areas.

[0003] On the other hand, however, conventional polyolefin-based films do not stretch uniformly and sufficiently along the shape of the base material when, for example, lapping or deep drawing is performed on the base material having various shapes as a surface material. In addition, there are problems in workability such as whitening and tearing in corners, etc., and there are also drawbacks such as low impact resistance at low temperatures, especially for surfaces that are required to have all of these characteristics in a well-balanced manner. The material cannot be fully satisfied with its use.

Therefore, rubber is added to polypropylene or a small amount of ethylene is added at the time of propylene polymerization, so that propylene and ethylene are randomly copolymerized, mainly to improve workability and impact resistance as a surface material. Methods have been proposed, such as causing the However, although these are somewhat improved in their disadvantages, they have not been sufficiently satisfied, and have also resulted in impaired characteristics such as reduced heat resistance and rigidity.

On the other hand, polyethylene is excellent in flexibility, impact resistance at low temperature, etc., and is used in various functional fields like propylene, but has poor rigidity.
It is not satisfied in the field where rigidity is required. Therefore,
Development of a film having both rigidity and workability as a surface material such as lapping workability by combining with a polypropylene film has been studied.

[0006] However, with the sophistication of applications, there is a strong demand for further improving the performance of the film itself and further improving the working efficiency. In particular, surface protection films, decorative films, civil engineering and construction fields. In the use of surface materials such as films for building materials in recent years,
There is a worldwide movement for environmentally friendly materials from the standpoint of environmental protection, and for example, the need to rapidly switch from polyvinyl chloride resin to polyolefin-based films has led to the demand for heat-resistant polyolefin-based films. At present, users are most and strongly demanding improvements in rigidity, impact resistance, workability as a surface material, and the like.

[0007]

The present invention is excellent in heat resistance, impact resistance, and rigidity, and has workability as a surface material in lapping or deep drawing on various substrate surfaces. It is an object of the present invention to provide a multilayer film.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a polyolefin-based film which has solved the above-mentioned problems, and as a result, have obtained a heat-resistant polyolefin film formed of a specific polyolefin-based resin material. It has been found that a film having excellent stiffness, rigidity and impact resistance and excellent workability as a surface material can be obtained.

That is, the present invention relates to a multilayer film comprising at least three layers of an outer layer, an intermediate layer and an inner layer, wherein the outer layer and the inner layer are each independently the following components (A) 50 to 50:
The intermediate layer is made of a resin material composed of 100% by weight and 50 to 0% by weight of the component (B).
Provided is a polyolefin-based multilayer film, which is formed of a resin material composed of about 95% by weight and 100% to 5% by weight of a component (D).

(A) Containing a structural unit derived from propylene in an amount of 90 mol% or more, and having an MFR of 0.1 to 50.
g / 10 minutes of crystalline polypropylene.

(B) A copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms having a structural unit derived from ethylene as a main component and having the following physical properties (B1) and (B2). (B1): MFR is 0.1 to 50 g / 10 minutes. (B2): The temperature of the maximum peak of the elution curve obtained by the temperature-rise elution fractionation is 15 to 85 ° C., the height of the peak is H, and the width of the peak at one third of the height is W. H / W value is 2 or more.

(C) A propylene homopolymer having the following physical properties (C1) and (C2) or propylene having a structural unit derived from propylene as a main component and C 2 or C 4
Copolymers with α-olefins of No. 20 to No. 20. (C1): MFR is 0.1 to 50 g / 10 minutes. (C2): The main melting peak obtained by differential scanning calorimetry (DSC) is in the range of 110 to 165 ° C.

(D) A copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms having a structural unit derived from ethylene as a main component and having the following physical properties (D1) and (D2). (D1) the MFR is 0.1 to 50 g / 10 min; (D2) the temperature of the maximum peak of the elution curve obtained by the temperature-rise elution fractionation is 15 to 85 ° C .; The width of the peak at one third height is W
H / W value is 2 or more.

The present invention also provides a film for protecting a surface, comprising the polyolefin-based multilayer film. The present invention also provides a decorative material film comprising the polyolefin-based multilayer film. Further, the present invention provides a film for building materials, comprising the polyolefin-based multilayer film.

The multilayer film of the present invention has heat resistance, rigidity,
Because of its excellent impact resistance and high elongation, it is not only suitable for use in conventional polyolefin-based films such as various packaging films, but also, in particular, can be wrapped on various substrates as a surface material. When deep drawing is performed, the film is stretched uniformly and sufficiently along the shape of the substrate when a tensile force is applied, so that whitening and tearing at corners and the like are less likely to occur and the substrate is not easily damaged. It has features and is useful as a surface protection film, especially as a surface protection film for a decorative material film, a building material film and the like.

[0016]

Embodiments of the present invention will be described below. The multilayer film of the present invention comprises at least three layers: an outer layer, an intermediate layer, and an inner layer. The outer layer and the inner layer are formed of a resin material composed of the component (A) alone or the component (A) and the component (B), and the intermediate layer is composed of the resin composed of the component (D) alone or the component (C) and the component (D). Formed from material. Here, component (B) and component (D)
Are components selected from the same category.

I. Resin material forming each layer (1) Component (A) Component (A) is composed of 9 structural units derived from propylene.
MFR (melt flow rate) is 0.1 to 50 g / 10 min, preferably 0.5 to 3 mol%.
The crystalline polypropylene is 0 g / 10 min. The MFR in this case is a value measured according to JIS-K6758. If the MFR is larger than the above range, the film strength decreases and the film formation becomes unstable. On the other hand, when the MFR is smaller than the above range, the resin pressure increases, the extrudability decreases, and the moldability deteriorates.

The crystalline polypropylene has a comonomer content of less than 10 mol% as determined by ¹³ C-nuclear magnetic resonance spectroscopy, that is, a crystalline polypropylene containing at least 90 mol% of structural units derived from propylene. Can be If the constituent unit derived from propylene is less than 90 mol%, heat resistance is undesirably reduced. In addition,
The comonomers that can be used here are ethylene, 1-
Butene, 1-pentene, 1-hexene, 1-octene,
Examples thereof include 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, and 4,4-dimethylpentene-1. The α-olefin used as a comonomer is not limited to one kind, but may be a terpolymer.
Multicomponent copolymers using more than one kind are also included as preferable ones. Specific examples include a propylene-ethylene binary copolymer, a propylene-butene binary copolymer, a propylene-ethylene-butene ternary copolymer, and the like.

The crystalline polypropylene of the component (A) is not particularly limited as long as it satisfies the physical properties described above, and any polypropylene can be used. Further, the production method is not particularly limited, and it can be produced by any known method so as to satisfy the above physical properties.

(2) Component (C) Component (C) is a propylene homopolymer having the following physical properties (C1) and (C2) or propylene having a structural unit derived from propylene as a main component and propylene having 2 carbon atoms. Or 4-2
0 is a copolymer with an α-olefin.

(C1): MFR of 0.1 to 50 g / 10
Min, preferably 0.5 to 30 g / 10 min. In addition,
The MFR in this case is a value measured according to JIS-K6758. If the MFR is larger than the above range, the film strength decreases, and the film formation becomes unstable. When the MFR is smaller than the above range, the resin pressure increases, and the extrudability decreases.

(C2): The main melting peak obtained by differential scanning calorimetry (DSC) is 110-165 ° C.
Preferably it is in the range of 135 to 165 ° C. If the melting peak temperature is higher than the above range, the transparency and impact resistance of the film decrease, and if the melting peak temperature is lower than the above range, the heat resistance of the film decreases, which is not preferable.

In the case of a copolymer of propylene and α-olefin, the comonomer α-olefin includes:
Those having 2 or 4 to 20 carbon atoms, specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1,4
-Methyl-hexene-1,4,4-dimethylpentene-
1 and the like. The α-olefin used as a comonomer is not limited to one type, and a multi-component copolymer using two or more types such as a terpolymer is also included as a preferable one. Preferably, propylene as the main component is contained in the copolymer in an amount of 75 mol% or more, and the comonomer is less than 25 mol%. Specifically, a propylene-ethylene binary copolymer, a propylene-butene binary copolymer,
A propylene-ethylene-butene terpolymer may be used.

The propylene homopolymer or propylene / α-olefin copolymer of the component (C) is not particularly limited as long as it satisfies the above-mentioned properties, and any polypropylene can be used. Further, the production method is not particularly limited, and it can be produced by any known method so as to satisfy the above physical properties.

(3) Component (B) and Component (D) Component (B) and component (D) are composed of ethylene having the following physical properties (B1 or D1) and (B2 or D2) and ethylene having 3 to 18 carbon atoms. α-
It is a copolymer with olefin.

(B1 or D1): MFR 0.1 to 50 g /
It is 10 minutes, preferably 0.5 to 30 g / 10 minutes. The MFR in this case is a value measured according to JIS-K7210. If the MFR is larger than the above range, the film strength decreases, and the film formation becomes unstable.
When the MFR is smaller than the above range, the resin pressure increases, and the extrudability decreases.

(B2 or D2): The temperature of the maximum peak of the elution curve obtained by fractionation with increasing temperature is 15 to 85 ° C.
The temperature is preferably 25 to 82 ° C., and the value of H / W is 2 or more, preferably 2, when the height of the peak is H and the width of the peak at one third of the height is W. 5 or more.

Here, the temperature rise elution fractionation (TREF: Te
(mperature Rising Elution Fraction) is the process of completely dissolving the polymer at a high temperature, then cooling it to form a thin polymer layer on the surface of the inert carrier, and then continuously or stepwise increasing the temperature to elute the eluted components. (Polymer) is recovered, its concentration is continuously detected, and the amount of the eluted component and the elution temperature are determined. A graph drawn by the elution fraction and the elution temperature is an elution curve, from which the composition distribution (molecular weight and crystallinity distribution) of the polymer can be measured. For details on the method and apparatus for measuring temperature rise elution fractionation (TREF), see the Journal of App.
lied Polymer Science, Vol. 26, Nos. 4217-423
1 (1981).

The shape of the elution curve obtained by TREF depends on the molecular weight and the distribution of crystallinity of the polymer. For example, there are one peak, two peaks, and three peaks. In the two-peak curve, a peak having a higher elution temperature has a higher elution fraction than a peak having a lower elution temperature. There are a case where the peak is large (the peak height is high) and a case where the peak with the high elution temperature has a smaller fraction (lower the height of the peak) than the peak with a low elution temperature. This will be described with reference to the drawings.
2 shows an elution curve in the case of one peak, FIG. 2 shows an elution curve in the case of two peaks, FIG. 3 shows an elution curve in the case of three peaks, and FIG. FIG. 2B shows a case where a peak having a higher elution temperature is higher than a peak having a lower elution temperature, and FIG. 2B shows a case where a peak having a higher elution temperature is higher than a peak having a lower elution temperature. Indicates that the peak height is low.

In the present invention, the maximum peak of the elution curve refers to the peak in the elution curve having one peak and the maximum peak in the elution curve having two or more peaks.
The peak at which the elution fraction is the maximum (the peak indicated by the symbol p in FIGS. 2 and 3) is shown. Further, in the present invention, H
As shown in FIGS. 1 to 3, / W is obtained by calculating the height of the maximum peak as H, and calculating the width at one third of the height as W. As shown in FIG. 1, when there is one peak, the peak is obtained from the height and width of the peak. In an elution curve having two or more peaks,
The valley between the maximum peak and another peak may be more than one-third of the height of the maximum peak, and depending on the shape, the width at the height of one-third of the height of the maximum peak May be the width of a curve formed from the maximum peak and the other peaks. In this case, the width of the entire curve formed from the maximum peak and the other peaks is represented by W (FIG. 2).
(A) and FIG. 3). Even if there are two or more peaks, if there is another peak whose valley between the maximum peak is less than one third of the height of the maximum peak, such another peak is present. Does not participate in the calculation of the width W (FIG. 2)
(B) and FIG. 3).

The TRE of the present invention thus determined
If the maximum peak temperature and H / W of the elution curve by F are within the above ranges, a polyolefin resin having a narrow composition distribution and uniform crystallinity can be obtained, and when a film is formed, transparency and
Improves the balance between impact resistance and heat resistance. On the other hand, TRE
If the temperature of the maximum peak of the elution curve by F is higher than the above range, a large amount of highly crystalline components are present in the resin, and the transparency and impact strength of the film are undesirably reduced. On the other hand, if the peak temperature is lower than the above range, the heat resistance of the film deteriorates, which is not preferable. On the other hand, if the value of H / W is smaller than the above range, the crystallinity distribution of the resin is too wide, and the transparency and impact resistance of the film are undesirably reduced.

The component (B) or component (D) having the above-mentioned physical properties is an ethylene / α-olefin copolymer containing a structural unit derived from ethylene as a main component. The α-olefin which is a comonomer is a 1-olefin having 3 to 18 carbon atoms, specifically, propylene, 1-olefin.
Butene, 1-pentene, 1-hexene, 1-octene,
Examples thereof include 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, and 4,4-dimethylpentene-1. The α-olefin used as a comonomer is not limited to one kind, but may be a terpolymer.
Multicomponent copolymers using more than one kind are also included as preferable ones. Specific examples include an ethylene / 1-hexene copolymer, an ethylene / 1-butene copolymer, an ethylene / 4-methylpentene-1 copolymer, and an ethylene / 1-octene copolymer.

The proportion of ethylene units in the copolymer is preferably at least 80 mol%, and the comonomer is preferably at least 20 mol%.
Is less than. Ethylene α of component (B) or component (D)
-The method for producing the olefin copolymer is not particularly limited, and the olefin copolymer can be produced by a known method so as to satisfy the above-mentioned properties (B1 or D1) and (B2 or D2). For example, as a known method for controlling the molecular weight and the distribution of crystallinity, a polymer having desired physical properties can be obtained by appropriately adopting a method of adjusting the polymerization temperature and the amount of comonomer.

The polymerization catalyst and the polymerization method are not particularly limited. Examples of the catalyst include a Ziegler catalyst (that is, a catalyst based on a combination of a supported or unsupported halogen-containing titanium compound and an organoaluminum compound) and a Phillips catalyst. (That is, the supported chromium oxide (C
r ⁶⁺ ), a Kaminski catalyst (ie, based on a combination of a supported or unsupported metallocene compound and an organoaluminum compound, particularly an alumoxane), and the like.

As a polymerization method, a slurry method in the presence of these catalysts, a gas phase fluidized bed method (for example,
No. 23011), a solution method, or a high-pressure bulk polymerization method at a pressure of 200 kg / cm ² or more and a polymerization temperature of 100 ° C. or more.

Component (B) or component (D) in the present invention
Since a relatively narrow composition distribution is desirable, it is particularly preferable to use a Kaminski type catalyst.

(4) Resin Material Forming Outer Layer and Inner Layer The resin material forming the outer layer and the inner layer is composed of the components (A) 50 to 50
100% by weight, preferably 75 to 100% by weight, and component (B) 50 to 0% by weight, preferably 25 to 0% by weight. That is, the component (B) is an arbitrary component that may not be included in the resin material forming the outer layer and the inner layer. On the other hand, if the amount of the component (A) is less than 50% by weight and the amount of the component (B) is more than 50% by weight, heat resistance is undesirably reduced.

The outer layer and the inner layer are each independently formed of the above-described resin material, and may be the same material as long as the above conditions are satisfied, and the components (A) and (B) Of different kinds of resin materials having different compounding ratios and physical properties.

(5) Resin Material Forming Intermediate Layer Component (C) and Component (D) in the resin material forming the intermediate layer
The proportion of component (C) is 0 to 95% by weight, preferably 0 to 75% by weight, and component (D) is 100 to 5% by weight, preferably 100 to 25% by weight. That is,
Component (C) is an optional component that may not be included in the resin material forming the intermediate layer. On the other hand, if the component (D) is less than 5% by weight and the component (C) is more than 95% by weight, the impact resistance is undesirably reduced.

(6) Other Components In addition to the components (A) to (D) described above, the resin material for forming the multilayer film of the present invention includes auxiliary additives generally used in resin molding materials and compositions. For example, antioxidants (of which phenol and phosphorus antioxidants are preferred), antiblocking agents, slip agents, heat stabilizers, ultraviolet absorbers, neutralizing agents, antifogging agents, coloring agents, and antistatic agents Agents, antibacterial agents, adhesives and the like can be compounded. Also,
A rubber component such as an ethylene / propylene random copolymer can be blended as long as the properties of the present invention are not impaired.

(7) Production of Resin Material The resin material of the present invention may be in the form of dry-blended each component and then directly charged into a hopper of a film forming machine.
Melting and kneading using a Banbury mixer, a kneader blender, etc., and forming pellets by a commonly used method,
It can also be used for film production. When the components (A) and (D) are used alone, they may be directly charged into a hopper of a film forming machine to produce a film.

II. Layer Structure of Multilayer Film The multilayer film of the present invention is not particularly limited as long as it has at least a three-layer structure including the above-described outer layer, intermediate layer, and inner layer in the layer structure. A resin layer having various functions may be provided (or inside) within a range that does not impair the effects of the present invention. For example, lamination of polyester such as nylon or polyethylene terephthalate, stretched polypropylene film or the like can improve functions such as mechanical strength, gas barrier property, and printing performance. In addition, printing can be performed directly on the outer layer or the inner layer. Furthermore, a surface treatment can be performed to improve printability, lamination properties, adhesive application properties, and the like. Examples of surface treatment methods include corona treatment, ozone treatment, plasma treatment, and flame treatment.

Further, between the outer layer and the inner layer, a layer other than the intermediate layer may be included as a constituent layer. That is, layers having various functions can be included as long as the effects of the present invention are not impaired. Examples of such a layer include an adhesive layer such as a modified polyolefin and an ethylene-vinyl acetate copolymer, a printing layer, a picture layer, and a nylon, eval, and polyester layer for imparting gas barrier properties.

The multilayer film of the present invention is usually formed so that the thickness of each layer is about 2 to 1000 μm, but the thickness and ratio of each layer are not particularly limited and can be arbitrarily selected. . Among them, the thickness of the intermediate layer is 20 to 99% of the total thickness of the film, preferably 30 to 99%.
When configured to be 95%, the effects of the present invention can be sufficiently exhibited.

The method for producing such a multilayer film of the present invention may be carried out in the same manner as the method for producing a film comprising a usual resin composition. For example, a film may be manufactured by dry blending each necessary component in advance and then directly into a hopper of a film forming machine to produce a film. Can also be manufactured. When the component (A) and / or the component (D) are used alone, they can be directly charged into a hopper of a film forming machine to produce a film.

The method for producing the film includes air-cooled inflation molding, air-cooled two-stage cooling inflation molding, T-die film molding, water-cooled inflation molding, and the like, and a film suitable for a packaging material can be obtained. Examples of the method for forming a multilayer include an extrusion lamination method, a thermal lamination method, a dry lamination method, a method of laminating each layer by a wet lamination method, a co-extrusion lamination method, and the like.

The multilayer film of the present invention is excellent in heat resistance, impact resistance and rigidity, and also has workability as a surface material in lapping or deep drawing on various substrate surfaces.

III. Applications (1) Surface protection film The multilayer film of the present invention is subjected to secondary processing steps such as printing, laminating, and application of an adhesive, and is then subjected to decorative plywood, metal plate,
It can be used as a film for protecting the surface of a substrate such as a coated steel plate or a synthetic resin plate. Such a surface protection film is used to protect the surface of a metal plate, a coated steel plate, or the like, or to prevent the surface from being damaged when the metal plate or the like is drawn.

The multilayer film of the present invention is excellent in lapping workability on a substrate and elongation during drawing. For example, the multilayer film can quickly follow the deformation of a metal plate or the like at the time of drawing. Is less likely to occur and scarcely damages the metal plate surface. The thickness of the surface protection film is not particularly limited, but is usually appropriately selected in the range of about 5 to 3000 μm.

(2) Film for decorative material The multilayer film of the present invention is a film for decorative material used on the surface of a decorative plate such as a cabinet for furniture or kitchen products.
Used as a sheet.

The decorative material generally has a laminated structure composed of a decorative material film layer including a surface layer, an adhesive layer, and a picture layer (printing layer), and a substrate.
As a method for producing a decorative material, for example, there is a method of laminating on a substrate using an adhesive or the like.

Examples of the substrate used include wood, plywood, laminated wood, wood substrates such as particle board and hard board, metal substrates such as steel plate, stainless steel plate and aluminum plate, and inorganic base materials such as gypsum board. And the like.

The multilayer film of the present invention has a lapping property, that is, when the substrate has irregularities or a complicated shape.
It has processing aptitude that can be bonded according to its shape. Specifically, there are no inconveniences such as cracks, cuts, and whitening in the bent portions of the film.

(3) Building material film The multilayer film of the present invention is used as a building material film for forming a surface material layer of a building material such as a floor material or a wall material. The building material usually has a structure in which a backing material is laminated on the back surface of the surface material layer.

The thickness of the surface material layer is not particularly limited, but is usually appropriately selected within a range of about 5 μm to 3 mm according to the situation. There is no particular limitation on the backing material, and paper or a material conventionally used as a backing material for conventional plastic building materials can be used.

The building material may be produced by laminating the surface material and the backing material by heat welding, or may be produced by laminating the surface material and the backing material via an adhesive layer. Good. For example, the building material film of the present invention and the backing material can be bonded and laminated by a press molding machine at a temperature not lower than the melting temperature of the resin. Further, the surface can be further subjected to embossing, printing, or the like. Since the multilayer film of the present invention is excellent in lapping workability in addition to mechanical strength and heat resistance, it exhibits good workability even when subjected to press working with a backing material. It is useful as an application film.

[0057]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. The measurement of physical properties and evaluation of film physical properties in the following Examples and Comparative Examples were carried out by the following methods.

(1) MFR (Melt Flow Rate) The MFR of the component (A) and the component (C) is JIS-K675.
The measurement was performed in accordance with the melt flow rate (condition: 230 ° C., load: 2.16 kg) of the polypropylene test method No. 8. The MFR of the component (B) and the component (D) is JIS-K7
The measurement was performed according to the melt flow rate (condition: 190 ° C., load: 2.16 kg) of the polyethylene test method No. 210.

(2) Comonomer concentration Determined by ¹³ C-nuclear magnetic resonance spectroscopy.

(3) Measurement of Melting Peak Temperature by Differential Scanning Calorimetry (DSC) Using a DSC manufactured by Seiko Co., Ltd., a sample amount of 5.0 mg was taken, kept at 200 ° C for 5 minutes, and then 10 ° C. to 40 ° C.
The crystallization was performed at a temperature lowering speed of 10 ° C./min, and the melting peak temperature and the melting end temperature when melting was performed at a temperature increasing speed of 10 ° C./min.

(4) Measurement of Elution Curve Obtained by Temperature-Increasing Elution Fractionation (TREF) Measurement of the elution curve by TREF in the present invention was carried out as follows. The measurement was carried out using a cloth separation apparatus (CFC T150A, manufactured by Mitsubishi Chemical Corporation) as a measurement apparatus according to the measurement method in the attached operation manual. This cross-separation apparatus comprises a temperature-rise elution fractionation (TREF) mechanism for fractionating a sample by utilizing a difference in dissolution temperature, and a size exclusion chromatograph (SEC) for further fractionating fractionated fractions by molecular size. Is an apparatus that is connected online.

First, the sample to be measured (ethylene / α
-Olefin copolymer) using a solvent (o-dichlorobenzene) to give a concentration of 4 mg / ml.
It was melted at ℃ and injected into a sample loop in the measuring device. The following measurements were performed automatically according to the set conditions.

The sample solution held in the sample loop is separated using a TREF column (internal diameter of 4 m filled with glass beads as an inert carrier) by utilizing the difference in dissolution temperature.
m, 150mm length stainless steel column attached to the device)
Was injected 0.4 ml. The sample was cooled at a rate of 1 ° C./min from 140 ° C. to 0 ° C. and coated on the inert carrier. At this time, from the high crystal component (the one that is easy to crystallize) to the low crystal component (the one that hardly crystallizes)
The polymer layer is formed on the surface of the inert carrier in this order. TR
After holding the EF column at 0 ° C. for an additional 30 minutes, 2 ml of the component dissolved at a temperature of 0 ° C. was added at a flow rate of 1 ml / min.
From REF column to SEC column (Showa Denko KK,
AD80M · S, 3 tubes). While fractionation by molecular size was being performed by SEC, the temperature of the TREF column was raised to the next elution temperature (5 ° C.) and maintained at that temperature for about 30 minutes. The measurement of each elution section by SEC was performed at intervals of 39 minutes. The following temperature is used as the elution temperature,
The temperature was raised stepwise.

Elution temperature (° C.): 0, 5, 10, 15, 2
0, 25, 30, 35, 40, 45, 49, 52, 5
5,58,61,64,67,70,73,76,7
9,82,85,88,91,94,97,100,1
02,120,140 ° C.

With respect to the solution fractionated by the molecular size in the SEC column, the absorbance in proportion to the concentration of the polymer was measured with an infrared spectrophotometer attached to the apparatus (wavelength 3.42 μm).
m, detection by stretching vibration of methylene) to obtain chromatograms for each elution temperature category. Using built-in data processing software,
A baseline of the chromatogram of each elution temperature section obtained by the above measurement was drawn and subjected to arithmetic processing. The area of each chromatogram was integrated and an integrated elution curve was calculated. Also,
This integrated elution curve was differentiated by temperature to calculate a differential elution curve. The plot of the calculation results was output to a printer. In the plot of the output differential elution curve, the elution temperature is plotted on the horizontal axis.
The difference was 89.3 mm per 0 ° C. and the differential amount on the vertical axis (elution fraction: the total integrated elution amount was standardized to 1.0, and the change at 1 ° C. was defined as the differential amount) at 76.5 mm per 0.1. .

Next, the temperature at the highest peak (maximum peak) from the differential elution curve is defined as the maximum peak temperature, and the peak height of this maximum peak is defined as H, and the height is one third of that. The value of H / W was calculated with the width at W as W.

(5) Formation of Film Component (A) and component (B) or component (A) alone,
The component (C) and the component (D) or the component (D) alone were co-extruded using a three-layer T-die molding machine under the following conditions to obtain a three-layer film.

(Molding conditions) Model: Placo T-die film molding machine Inner layer: screw diameter: 20 mmφ, L / D: 25, temperature: 240 ° C. Intermediate layer: screw diameter: 35 mmφ, L / D: 28, temperature 240 ° C outer layer: screw diameter; 20 mmφ, L / D; 25, temperature; 240 ° C die lip; 0.8 mm die temperature; 240 ° C chill roll temperature; 30 ° C air gap; 60 mm take-up speed; 8 m / min film thickness; 100μ layer thickness ratio: inner layer / intermediate layer / outer layer = 1/2/1

(6) Method for evaluating physical properties of film a. 120 ° C. Heat Resistance The outer and inner surfaces of a 100 mm × 100 mm sample film were placed in a sterilizer and placed on top of each other, and a load of 15 kg was applied from above. Thereafter, the pressure was increased, the ambient temperature was increased to 120 ° C., and the temperature was maintained at 120 ° C. for 30 minutes. And
The sample film was taken out and evaluated according to the following criteria. A film having a rating of ○ has heat resistance and is excellent. X: When films are not peeled off due to fusion. ：: When the film peeled off without resistance without fusing.

B. Vertical Tensile Modulus (Rigidity) In accordance with ISO-R1184, the obtained sample film was measured for tensile modulus in the vertical direction using an Instron-type autograph. The higher the value, the higher the rigidity and the better.

C. Impact strength (Punching impact strength) According to JIS-8134, the obtained film
The sample was allowed to stand for 24 hours or more in an atmosphere of ° C., adjusted in condition, and then measured in the same atmosphere. The larger the value, the better the impact resistance.

D. Lapping processability An inner layer surface of the obtained film was subjected to a corona treatment, and an adhesive mainly composed of an ethylene-vinyl acetate copolymer resin was applied to the treated surface. Without applying heat, the particles were stuck together on the particle board having irregularities so that the inner layers were in contact with each other, the whitening state was confirmed, and the lapping workability was evaluated based on the following criteria. ×: Whitening occurs at the corners. ：: No whitening occurs.

<Example 1> Crystalline polypropylene having a MFR of 5.0 g / 10 min and a comonomer content of 4.0 mol% was used alone as the component (A) in the outer layer and the inner layer. Nippon Polychem Co., Ltd. as component (D)
Manufactured by Kernel 54FTK (comonomer; 1-
Hexene, MFR; 3.5 g / 10 min, maximum peak temperature of TREF elution curve; 58 ° C., H / W; 3.9, Kernel is a registered trademark. ) Was used alone, a three-layer T-die molding was performed under the above conditions, and the three-layer film was evaluated. The results of the evaluation are as shown in Table 1.

<Example 2> For the outer layer and the inner layer, crystalline polypropylene having an MFR of 5.0 g / 10 min and a comonomer content of 4.0 mol% was used alone as the component (A). Nippon Polychem Co., Ltd. as component (D)
“Kernel 64FTK” (comonomer; 1-hexene, MFR; 3.5 g / 10 min, maximum peak temperature of TREF elution curve; 62 ° C., H / W: 3.9) alone under the above conditions Layer T die molding was performed and the three-layer film was evaluated. The results of the evaluation are as shown in Table 1.

Example 3 In the outer layer and the inner layer, a crystalline polypropylene having an MFR of 5.0 g / 10 min and a comonomer content of 4.0 mol% was used as the component (A), and Nippon Polychem (Component B) was used as the component (B). Kernel 54FT
K "(MFR; 3.5 g / 10 min, maximum peak temperature of TREF elution curve; 58 ° C, H / W; 3.9), component (A): component (B) = 75:25 (weight ratio) ), And for the intermediate layer, as the component (D), "Kernel 54FTK"(comonomer; 1-hexene, MFR; 3.5 g / 10 min, TRE, manufactured by Nippon Polychem Co., Ltd.)
2. Maximum peak temperature of F elution curve; 58 ° C, H / W;
Using 9) alone, three-layer T-die molding was performed under the above conditions, and the three-layer film was evaluated. The results of the evaluation are as shown in Table 1.

Example 4 In the outer layer and the inner layer, crystalline polypropylene having an MFR of 5.0 g / 10 minutes and a comonomer content of 4.0 mol% was used as the component (A), and Nippon Polychem (component (B)) was used. Kernel 54FT
K "(MFR; 3.5 g / 10 min, maximum peak temperature of TREF elution curve; 58 ° C, H / W; 3.9), component (A): component (B) = 75:25 (weight ratio) )), And in the intermediate layer, as the component (C), M
FR: 5.0 g / 10 min, melting peak temperature: 148 ° C. A propylene-based copolymer having a component (D) of “Kernel 54FTK” (MFR: 3.5 g, manufactured by Nippon Polychem Co., Ltd.)
/ 10 min, maximum peak temperature of TREF elution curve; 58
C, H / W; 3.9) to obtain component (C): component (D).
= 25:75 (weight ratio)
Three-layer T-die molding was performed under the above conditions, and the three-layer film was evaluated. The results of the evaluation are as shown in Table 1.

Example 5 In the outer layer and the inner layer, crystalline polypropylene having a MFR of 10 g / 10 minutes and a comonomer content of 0 mol% was used alone as the component (A), and the component (D) was used in the intermediate layer. "Kernel 54FTK" manufactured by Nippon Polychem Co., Ltd. (MFR: 3.5 g / 10 min, TR
2. Maximum peak temperature of EF elution curve; 58 ° C, H / W;
Using 9) alone, three-layer T-die molding was performed under the above conditions, and the three-layer film was evaluated. The results of the evaluation are as shown in Table 1.

<Comparative Example 1> Crystalline polypropylene having an MFR of 5.0 g / 10 min and a comonomer content of 4.0 mol% was used alone as the component (A) in the outer layer and the inner layer. MFR as component (C); 5.0 g /
Using a propylene copolymer alone having a melting peak temperature of 148 ° C. for 10 minutes, a three-layer T-die molding was performed under the above conditions, and a three-layer film was evaluated. The results of the evaluation are as shown in Table 2. Although heat resistance and rigidity are excellent, it is not preferable because impact strength is inferior.

<Comparative Example 2> In the outer layer and the inner layer, "Kernel 54FT" manufactured by Nippon Polychem Co., Ltd. was used as the component (B).
K ”(MFR: 3.5 g / 10 min, maximum peak temperature of TREF elution curve; 58 ° C., H / W: 3.9) was used alone, and Nippon Polychem Co., Ltd. was used as the component (D) in the intermediate layer. )
“Kernel 54FTK” (MFR; 3.5 g / 10
Min, maximum peak temperature of TREF elution curve; 58 ° C, H /
W; 3.9) was used alone, and a three-layer T-die was formed under the above conditions to evaluate a three-layer film. Table 2 shows the evaluation results.
As shown in FIG. Although the impact strength is excellent, it is not preferable because it has no rigidity and has poor heat resistance.

Comparative Example 3 In the outer layer and the inner layer, crystalline polypropylene having an MFR of 5.0 g / 10 minutes and a comonomer content of 4.0 mol% was used as a component (A), and Nippon Polychem (a component (B)) was used. Kernel 54FT
K "(MFR: 3.5 g / 10 min, maximum peak temperature of TREF elution curve; 58 ° C, H / W; 3.9), component (A): component (B) = 40:60 (weight ratio) ) Is used, and as the component (D), “Kernel 54FTK” (MFR; manufactured by Nippon Polychem Co., Ltd.) is used for the intermediate layer.
Using 3.5 g / 10 min, the maximum peak temperature of the TREF elution curve; 58 ° C., H / W: 3.9) alone, three-layer T-die molding was performed under the above conditions, and the three-layer film was evaluated.
The results of the evaluation are as shown in Table 2. Although the impact strength is excellent, it is not preferable because it lacks rigidity and has poor heat resistance.

<Comparative Example 4> Crystalline polypropylene having an MFR of 5.0 g / 10 minutes and a comonomer content of 14.0 mol% was used alone as the component (A) in the outer layer and the inner layer. Nippon Polychem Co., Ltd. as component (D)
“Kernel 54FTK” (MFR; 3.5 g / 10
Min, maximum peak temperature of TREF elution curve; 58 ° C, H /
W; 3.9) was used alone, and a three-layer T-die was formed under the above conditions to evaluate a three-layer film. Table 2 shows the evaluation results.
As shown in FIG. Although the impact strength is excellent, there is no rigidity,
Further, the heat resistance is also slightly inferior, which is not preferable.

<Comparative Example 5> Crystalline polypropylene having an MFR of 5.0 g / 10 min and a comonomer content of 4.0 mol% was used alone as the component (A) in the outer layer and the inner layer. Nippon Polychem Co., Ltd. as component (D)
Manufactured by Novatec LL UF422 (MFR;
0.8 g / 10 min, maximum peak temperature of TREF elution curve; 89 ° C., H / W: 0.85. Using Novatec alone), three-layer T-die molding was performed under the above conditions, and the three-layer film was evaluated. The results of the evaluation are as shown in Table 2. Although heat resistance and rigidity are excellent, impact strength is poor, which is not preferable.

<Comparative Example 6> Crystalline polypropylene having an MFR of 5.0 g / 10 min and a comonomer content of 4.0 mol% was used alone as the component (A) in the outer layer and the inner layer. Nippon Polychem Co., Ltd. as component (D)
Novatec HD HJ560 (MFR; 7 g / 1)
0 min, maximum peak temperature of TREF elution curve; 98 ° C., H
/ W; 8.7) was used alone, and a three-layer T-die was formed under the above conditions to evaluate a three-layer film. The results of the evaluation are as shown in Table 2. Although heat resistance and rigidity are excellent, impact strength is poor, which is not preferable.

[0084]

[Table 1]

[0085]

[Table 2]

[0086]

The multilayer film of the present invention has excellent heat resistance, impact resistance, and rigidity, and also has workability as a surface material in lapping or deep drawing on various substrate surfaces. It is useful as a film for packaging, and particularly as a surface protective film for films for decorative materials and films for building materials.

[Brief description of the drawings]

FIG. 1 shows an elution curve for a single peak.

FIG. 2 shows an elution curve for two peaks. FIG.
2A shows a case where a peak having a higher elution temperature has a higher peak height than a peak having a lower elution temperature, and FIG. 2B shows a case where a peak having a higher elution temperature has a higher peak height than a peak having a lower elution temperature. Is low.

FIG. 3 shows an elution curve for three peaks.

[Explanation of symbols]

 p: maximum peak

Claims (4)

[Claims] 1. A multilayer film comprising at least three layers of an outer layer, an intermediate layer and an inner layer, wherein the outer layer and the inner layer are each independently 50 to 100% by weight of the following component (A) and 50 to 0% of the component (B): The intermediate layer is formed of the following component (C) 0 to 95% by weight and component (D).
A polyolefin-based multilayer film formed of a resin material consisting of 100 to 5% by weight. (A) 90 mol% of the structural unit derived from propylene
A crystalline polypropylene containing the above amount and having an MFR of 0.1 to 50 g / 10 minutes. (B) Ethylene and carbon number 3 having a structural unit derived from ethylene as a main component and having the following physical properties (B1) and (B2).
And α-olefin copolymers of No. 18 to No. 18. (B1): MFR is 0.1 to 50 g / 10 minutes. (B2): The temperature of the maximum peak of the elution curve obtained by temperature-rise elution fractionation is 15 to 85 ° C., the height of the peak is H, and the width of the peak at one-third the height is W. H / W value is 2 or more. (C) propylene homopolymer having the following physical properties (C1) and (C2) or propylene having a structural unit derived from propylene as a main component and α- having 2 or 4 to 20 carbon atoms.
Copolymer with olefin. (C1): MFR is 0.1 to 50 g / 10 minutes. (C2): The main melting peak obtained by differential scanning calorimetry (DSC) is in the range of 110 to 165 ° C. (D) a structural unit derived from ethylene as a main component,
Ethylene with the following physical properties (D1) and (D2) and carbon number 3
And α-olefin copolymers of No. 18 to No. 18. (D1) the MFR is 0.1 to 50 g / 10 min; (D2) the temperature of the maximum peak of the elution curve obtained by the temperature-rise elution fractionation is 15 to 85 ° C .; The width of the peak at one third height is W
H / W value is 2 or more. 2. A surface protection film comprising the polyolefin-based multilayer film according to claim 1. 3. A film for a decorative material, comprising the polyolefin-based multilayer film according to claim 1. 4. A film for building materials, comprising the polyolefin-based multilayer film according to claim 1.