JP2008279600A - Heat-sealable laminated body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-sealable laminated body which can be manufactured without requiring a laminating process and an intermediate layer, and has a heat seal strength and a high tensile modulus enough for packaging a heavy article. <P>SOLUTION: The laminated body includes a heat fusible layer and a substrate layer. As the heat fusible layer, a propylene-ethylene random block copolymer which is manufactured by polymerizing 30-70 wt.% propylene-ethylene random copolymer component (A) with an ethylene content of 1-7 wt.% using a metallocene catalyst in a first process, and polymerizing 70-30 wt.% propylene-ethylene random copolymer component (B) with an ethylene content of 6-15 wt.% more than the component (A) in a second process, and has a tanδ curve with a single peak at ≤0°C in a temperature-loss tangent curve obtained by a solid viscoelastic measurement is used. As the substrate layer, a polypropylene resin composition with ΔHm (heat of fusion) of 50-96 mJ/mg is used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-sealable laminate and a package obtained using the same, and more particularly to a heat-sealable laminate having high heat-seal strength and tensile elastic modulus and a package obtained using the same. is there.

Conventionally, as a heat-sealable laminate used as a package, generally, a co-extrusion laminated polypropylene resin film in which a low melting point polyolefin resin is laminated on a polypropylene resin, an unstretched polyethylene resin film, or a polypropylene resin A laminated polypropylene resin film obtained by laminating a resin film and a stretched polypropylene resin film is often used.
However, co-extrusion laminated polypropylene resin film in which low melting point polyolefin resin is laminated on polypropylene resin has some degree of seal strength, but does not have enough seal strength to package heavy objects such as water, and is not stretched A laminated polypropylene resin film in which a polyethylene resin film or a polypropylene resin film and a stretched polypropylene resin film are laminated has sufficient sealing strength, but requires a laminating process using an organic solvent, etc. Moreover, it is not preferable from the aspect of influence on the global environment.

In contrast, the adhesive layer and intermediate layer are provided between the base layer of the co-extruded laminated film and the heat-sealing layer to increase the interlayer strength. There has been proposed an improvement in strength (for example, see Patent Documents 1 and 2). In addition, a method (for example, see Patent Document 3) has been proposed in which the heat-sealing strength and suitability for an automatic packaging machine are improved in a balanced manner by increasing the thickness of the heat-fusible layer of the coextruded laminated film. However, these improved technologies are not preferable because they have a special layer structure as compared with the conventional heat-sealable laminates, which requires modification of equipment such as dies and extruders, and requires an economical burden.
Furthermore, by using a propylene-ethylene random block copolymer having specific conditions for the heat-sealing layer, polypropylene-based biaxial stretching that improves heat sealability, low-temperature heat sealability, transparency, blocking resistance, etc. in a well-balanced manner. An invention relating to a multilayer film (see, for example, Patent Document 4) is disclosed. However, by simply using a propylene-ethylene random block copolymer only for the heat-fusible layer, sufficient heat seal strength cannot be expressed (in the examples, a maximum of 780 g / 15 mm). The current situation is that the heat seal strength is not sufficient for packaging heavy objects.
Furthermore, by adjusting the MFR of the propylene-ethylene random block copolymer used for the heat-sealing layer, or by increasing the thickness of the heat-sealing layer, a high heat seal strength is imparted (for example, Patent Document 5). However, since the MFR of the resin of the heat-fusible layer is increased, the moldability may be deteriorated, and it cannot be said that the product performance and quality are sufficient.
Japanese Patent Laid-Open No. 10-76618 Japanese Patent Laid-Open No. 2003-225979 JP-A-7-329260 JP 2005-305767 A JP 2005-305782 A

  In view of the above-mentioned problems, the object of the present invention is not to require a laminating process or an intermediate layer, and can be easily manufactured with conventional equipment, and has a sufficient heat seal strength and high tensile elastic modulus for packaging heavy objects. It is providing the heat-sealable laminated body which has, and a package obtained using the same.

As a result of intensive studies to solve the above-mentioned problems, the present inventors use a specific propylene-ethylene random block copolymer for the heat-fusible layer and a specific polypropylene resin composition for the base material layer. As a result, it was found that a heat-sealable laminate having a sufficient heat-seal strength and high tensile elastic modulus for wrapping heavy objects and a package obtained using the same can be obtained, and the present invention has been completed. It was.
In particular, when a specific propylene-ethylene random block copolymer is used for the heat-sealing layer, surprisingly, ΔHm of the polypropylene-based resin composition used for the base material layer and the heat of the heat-sealable laminate obtained are surprising. It has been found that the seal strength is in a proportional relationship, and based on the knowledge, it becomes possible to set the heat seal strength of the obtained heat-sealable laminate at the stage of material design. It has been found that a heat-sealable laminate having a good balance with the tensile modulus and a package obtained using the same can be obtained.

That is, according to the first invention of the present invention, there is provided a laminate comprising a heat-fusible layer and a base material layer, the following condition (i) obtained using a metallocene-based catalyst for the heat-fusible layer: A propylene-ethylene random block copolymer satisfying (ii) is used, and a polypropylene resin composition having a ΔHm (heat of fusion) measured in accordance with JIS K7122 of 50 to 96 mJ / mg is used for the base material layer. A heat-sealable laminate is provided.
(I) 30 to 70% by weight of the propylene-ethylene random copolymer component (A) having an ethylene content of 1 to 7% by weight in the first step, and then 6 to 15% by weight of the component (A) in the second step. % Propylene-ethylene random copolymer component (B) containing a large amount of ethylene is successively polymerized in an amount of 70 to 30% by weight. (Ii) In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve is 0 ° C. or less. Have a single peak

  According to the second invention of the present invention, there is provided a heat-sealable laminate having a heat seal strength of 900 g / 15 mm or more in the first invention.

  According to a third aspect of the present invention, there is provided a heat sealable laminate according to the first or second aspect, wherein the heat-sealing layer has a thickness of 2 to 4 μm.

  According to the fourth invention of the present invention, in any one of the first to third inventions, the tensile elastic modulus in the flow direction (MD) of the laminate measured according to JIS K7127 is orthogonal to the flow direction. A heat-sealable laminate is provided in which the sum of the tensile modulus in the direction (TD) is 4000 MPa or more.

  According to the fifth invention of the present invention, in any one of the first to fourth inventions, the polypropylene resin composition used for the base material layer is composed of two or more kinds of polypropylene resins. A heat-sealable laminate is provided.

  Moreover, according to the sixth invention of the present invention, in any one of the first to fifth inventions, the polypropylene resin composition used for the base material layer contains a petroleum resin. A heat-sealable laminate is provided.

  Moreover, according to 7th invention of this invention, the package characterized by using the heat-sealable laminated body of any one of 1st-6th invention is provided.

The heat-sealable laminate of the present invention does not require a laminating step or an intermediate layer, and can be easily produced with conventional equipment, and has a heat-seal strength sufficient for packaging heavy objects and a high tensile elastic modulus.
In the present invention, in order to improve the heat seal strength of the heat-sealable laminate, it is not sufficient to simply examine the heat-sealing layer, taking into account the synergistic effect with the base material layer. The present invention has succeeded in providing an excellent synergistic effect by specifying the resin used for the heat-fusible layer and the resin used for the base material layer, In addition to obtaining a heat-sealable laminate having a balance with the tensile elastic modulus and a package using the same, a method capable of assuming heat-seal strength at the resin design stage was also established.

The present invention uses a base material layer obtained from a polypropylene resin composition having a ΔHm (heat of fusion) measured in accordance with JIS K7122 of 50 to 96 mJ / mg and a metallocene catalyst, and (i) ethylene in the first step. After propylene-ethylene random copolymer component (A) having a content of 1 to 7% by weight is polymerized in an amount of 30 to 70% by weight, propylene containing 6 to 15% by weight of ethylene more than component (A) in the second step -It is obtained by sequential polymerization of 70 to 30% by weight of ethylene random copolymer component (B), and (ii) in the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve is single at 0 ° C or less. It is a heat-sealable laminate comprising a heat-sealing layer obtained from a propylene-ethylene random block copolymer having a peak.
Below, a base material layer, a heat sealing | fusion layer, a heat-sealable laminated body, etc. are demonstrated in detail.

[1] Base material layer (1) Component of polypropylene resin composition The polypropylene resin composition used for the base material layer of the heat-sealable laminate of the present invention is composed of a polypropylene resin and other components. It is a thing. Each component will be described below.
(I) Polypropylene resin The polypropylene resin used in the polypropylene resin composition may be either a homopolymer of propylene or a copolymer of propylene and another α-olefin. May be any of a random, block or graft copolymer of propylene and an α-olefin whose main component is a structural unit derived from propylene.
The α-olefin used as a comonomer is preferably ethylene or an α-olefin having 4 to 18 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 etc. can be mentioned. Moreover, as an alpha olefin, 1 type or the combination of 2 or more types may be sufficient.
Among these, as the polypropylene resin used in the present invention, propylene homopolymer, propylene-ethylene random copolymer, propylene-ethylene-butene random copolymer, and propylene-ethylene random obtained by sequential polymerization used in the present invention. A block copolymer is preferable, and two or more of these may be used in combination.

The amount of the propylene unit in the propylene / α-olefin copolymer is not particularly limited, but is preferably 88 to 99.5% by weight, more preferably 91 to 99% by weight.
Here, the propylene unit and the α-olefin unit are values measured by a ¹³ C-NMR method under the following conditions.
Model: GSX-400 manufactured by JEOL Ltd. or equivalent equipment (carbon nuclear resonance frequency of 100 MHz or more)
Solvent: o-dichlorobenzene / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / mL

  In addition, as a polypropylene-type resin used for this invention, in the range which does not impair the characteristic of this invention significantly, a propylene, unsaturated carboxylic acid or its derivative (acrylic acid, maleic anhydride, etc.), an aromatic vinyl monomer ( A copolymer with styrene or the like may be used.

The polypropylene resin used in the present invention preferably has a melt flow rate (MFR) of 0.5 to 10 g / 10 minutes, particularly preferably 1 to 5 g / 10 minutes, from the viewpoint of film formability and the like. .
Here, MFR is a value measured at a heating temperature of 230 ° C. and a load of 21.2 N in accordance with JIS K7210.

Such a polypropylene resin can be produced by a known method using a so-called Ziegler-Natta catalyst or a metallocene catalyst, which contains magnesium, titanium, halogen, and an electron donor as essential components.
Those polymerized with a metallocene catalyst are preferred because they have an excellent balance of transparency, rigidity and impact resistance.
Examples of the metallocene catalyst include transition metal compounds belonging to Group 4 of the periodic table (so-called metallocene compounds) containing a ligand having a cyclopentadienyl skeleton such as dimethylsilylene bis (2-methylindenyl) zirconium dichloride, methylalumoxane, and the like. A promoter capable of reacting with a metallocene compound such as an organoaluminum oxy compound, a boron compound such as N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, or an ion-exchange layered silicate, and activated into a stable ionic state; And a catalyst comprising an organoaluminum compound such as triethylaluminum used as necessary.
In the present invention, a commercially available product can be used as the polypropylene-based resin, and examples thereof include Novatec PP and Wintech manufactured by Nippon Polypro Co., Ltd.

(Ii) Other compounding materials In addition to the polypropylene resin described above, other compounding materials may be added to the polypropylene resin composition used in the present invention as long as the effects of the present invention are not impaired.
Examples of other compounding materials include thermoplastic resins other than polypropylene resins, specifically, ethylene polymers, butene polymers, alicyclic hydrocarbon resins, styrene resins, and the like. It is desirable to blend within a range of 50% by weight or less.
Examples of the alicyclic hydrocarbon resin include petroleum resins, terpene resins, rosin resins, coumarone indene resins, and hydrogenated derivatives thereof. Among these, those having no polar group and those having a hydrogenation rate of 95% or more by adding hydrogen are preferred, and petroleum resins or hydrogenated derivatives of petroleum resins are more preferred. In addition, when such a petroleum resin is blended in a polypropylene resin composition, the resulting heat-sealable laminate has a low ΔHm due to the blending of an amorphous petroleum resin, improving the heat seal strength. It is preferable. The petroleum resin is desirably blended in the range of 5 to 40% by weight based on the total amount of the resin.
Examples of the petroleum resin include commercially available products such as Alcon manufactured by Arakawa Chemical Industries, Ltd., and Opera manufactured by ExxonMobil Co., Ltd.

Examples of other compounding materials include stabilizers such as antioxidants and weathering agents used in polypropylene resins, additives such as processing aids, colorants, antistatic agents, lubricants, and antiblocking agents. .
Among these additives, those containing an antistatic agent are particularly preferable. Preferable examples of the antistatic agent include fatty acid esters of glycerin, alkylamines, ethylene oxide adducts of alkylamines, and fatty acid esters thereof.

(2) Properties of polypropylene resin composition [Delta] Hm of the polypropylene resin composition used in the present invention is 50 to 96 mJ / mg, preferably 60 to 94 mJ / mg, and more preferably 70 to 92 mJ / mg. . When the ΔHm of the polypropylene-based resin composition exceeds 96 mJ / mg, the resulting heat-sealable laminate cannot have sufficient heat seal strength to package heavy objects, and ΔHm is less than 50 mJ / mg. Since the crystallinity of the resin is low, film formation becomes difficult.
ΔHm (heat of fusion) is originally a scale representing the degree of crystallinity of the resin. As the heat-sealable laminate of the present invention, the propylene-ethylene random block copolymer of the present invention is added to the heat-sealing layer. When used, it becomes clear in the present invention that ΔHm of the polypropylene resin composition used for the base material layer and the heat seal strength of the resulting heat-sealable laminate are established in the present invention. Examples and Comparative Examples described later It is clear from
Here, ΔHm is a value measured according to JIS K7122.

In addition, as a polypropylene resin used for the polypropylene resin composition used in the present invention, a resin having ΔHm in the range of 50 to 96 mJ / mg may be used alone, or two or more kinds of polypropylene resins may be combined to obtain ΔHm. May be used in a range of 50 to 96 mJ / mg. Since it is easy to adjust ΔHm, it is preferable to use a combination of two or more types of polypropylene resins, whereby a heat-sealable laminate having a desired heat-seal strength can be easily obtained.
Moreover, it is possible to adjust (DELTA) Hm of a polypropylene resin composition also by adding another compounding material with respect to single or two or more types of polypropylene resins.

(3) Production of polypropylene-based resin composition The polypropylene-based resin composition used in the present invention is a Henschel mixer, a super mixer, a V blender, a tumbler mixer, a ribbon mixer, a Banbury mixer, and a kneader after measuring the necessary amount of the above components. A method of mixing into a known mixer such as a blender and mixing. After mixing, the mixture is further melt-kneaded at a temperature of 160 to 300 ° C., preferably 180 to 280 ° C. in a known kneader such as a single screw or twin screw extruder. And pelletizing by pelletizing. At this time, the polypropylene resin composition may be obtained by mixing the components constituting them at once, and the components previously divided into two or more and mixed or pelletized, It may be obtained by mixing at the time of use.

[2] Heat-sealable layer The heat-sealable layer used in the heat-sealable laminate of the present invention is a propylene-ethylene random block copolymer having the following characteristics obtained by sequential polymerization using a metallocene catalyst. Coalescence is used.

1. Propylene-ethylene random block copolymer The propylene-ethylene random block copolymer used in the present invention is a first step in which 30 propylene-ethylene random copolymer components (A) having an ethylene content of 1 to 7% by weight are used. After polymerization of ˜70 wt%, in the second step, 70-30 wt% of the propylene-ethylene random copolymer component (B) containing 6 to 15 wt% more ethylene than in the first step is successively polymerized to obtain a solid In the temperature-loss tangent curve obtained by viscoelasticity measurement, the tan δ curve is a propylene-ethylene random block copolymer having a single peak at 0 ° C. or lower.
The propylene-ethylene random block copolymer referred to here is a propylene-ethylene random copolymer component (A) (hereinafter referred to as component (A)) and a propylene-ethylene random copolymer component (B). (Hereinafter referred to as “component (B)”) is a block copolymer under the common name obtained by sequential polymerization, and is a component in which component (A) and component (B) are necessarily combined in a block form. Not necessarily.

The above conditions will be described below.
(1) Ethylene content in component (A) ([E] A)
The range of the ethylene content in component (A) is 1 to 7% by weight, preferably 2 to 6% by weight. When the ethylene content is less than 1% by weight, the melting point of the block copolymer is increased, and as a result, the heat seal temperature is increased, which is not preferable. When the ethylene content exceeds 7% by weight, the crystallinity of the heat-sealing layer becomes too low, and the blocking resistance of the film deteriorates, which is not preferable.

(2) Ethylene content in component (B) ([E] B)
The range of the ethylene content of component (B) is defined by the difference [E] B- [E] A ([E] gap) from the ethylene content of component (A). [E] gap needs to be in the range of 6 to 15% by weight, and preferably in the range of 7 to 13% by weight.
Component (B) is an important component for imparting flexibility to the propylene-ethylene random block copolymer and increasing the heat seal strength. When [E] gap is below the above range, Flexibility is insufficient, and improvement in heat seal strength is not achieved. On the contrary, when exceeding the said range, since a component (A) and a component (B) take a phase-separation structure, transparency of a film deteriorates or in the interface of a component (A) and a component (B). Is not preferable because the effect of improving the heat seal strength is not seen.

(3) Ratio of component (A) and component (B) Because the flexibility of the propylene-ethylene random block copolymer is improved by increasing the amount of component (B), the heat seal strength is improved. In order to exhibit flexibility, the ratio W (B) of the component (B) to the entire block copolymer needs to be at least 30% by weight, preferably 40% by weight or more.
When W (B) is less than 30% by weight, the flexibility cannot be fully exhibited and the heat seal strength cannot be improved, or the crystallinity of the component (A) is extremely reduced in order to make it flexible. It is necessary to drop the film, and accordingly, the crystal melting temperature becomes too low, so that the blocking resistance of the film is deteriorated.
On the other hand, if W (B) is excessively increased, there is a problem that the blocking resistance is remarkably deteriorated. Therefore, W (B) must be 70% by weight or less, preferably 65% by weight or less. is there.
As a result, W (B) needs to be in the range of 30 to 70% by weight, more preferably 40 to 65% by weight. Further, W (A) needs to be in the range of 70 to 30% by weight, more preferably 60 to 35% by weight.

(4) Measurement of [E] A and [E] B and W (A) and W (B) Measurement of [E] A and [E] B and W (A) and W (B) Although it is possible to specify by the material balance (material balance), in order to specify these more accurately, it is desirable to use the following analysis.
(I) Identification of W (A) and W (B) by temperature-temperature elution fractionation (TREF) The technique for evaluating the crystallinity distribution of a propylene-ethylene random copolymer by TREF is well known to those skilled in the art. Yes, for example, detailed measurement methods are shown in the following documents.
G. Glockner, J. et al. Appl. Polym. Sci. : Appl. Polym. Symp. 45, 1-24 (1990)
L. Wild, Adv. Polym. Sci. 98, 1-47 (1990)
J. et al. B. P. Soares, A .; E. Hamielec, Polymer; 36,
8, 1639-1654 (1995)

  The propylene-ethylene random block copolymer in the present invention is greatly different in the crystallinity of each of the components (A) and (B), and is produced using a metallocene catalyst so that each crystallinity distribution is different. Since it is narrow, there are very few intermediate components of both, and it is possible to discriminate | determine both accurately by TREF.

A specific method will be described with reference to the figure showing the elution amount and the elution amount integration by TREF in FIG. In the TREF elution curve (plot of elution amount versus temperature), components (A) and (B) show their elution peaks at T (A) and T (B), respectively, due to the difference in crystallinity, and the difference is sufficiently large. Separation is possible at an intermediate temperature T (C) (= {T (A) + T (B)} / 2).
In addition, the lower limit of the TREF measurement temperature is −15 ° C. in the apparatus used for this measurement, but in the case where the crystallinity of the component (B) is very low or an amorphous component, There may be no peak in the range. (In this case, the concentration of the component (B) dissolved in the solvent is detected at the measurement temperature lower limit (ie, −15 ° C.).)
At this time, T (B) is considered to exist below the lower limit of the measurement temperature, but the value cannot be measured. In such a case, T (B) is the lower limit of the measurement temperature. Defined as ° C.
Here, if the integrated amount of the components eluted up to T (C) is defined as W (B) wt%, and the integrated amount of the component eluted at T (C) or higher is defined as W (A) wt%, W (B) Almost corresponds to the amount of the component (B) having low crystallinity or amorphousness, and the integrated amount W (A) of the component eluted at T (C) or higher is the component (A) having relatively high crystallinity. Almost corresponds to the amount of. The elution amount curve obtained by TREF and the above-described methods for calculating the various temperatures and amounts obtained therefrom are performed as illustrated in FIG.

(Ii) Method for measuring TREF In the present invention, TREF is specifically measured as follows.
A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / mL BHT) at 140 ° C. to prepare a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Thereafter, o-dichlorobenzene (containing 0.5 mg / mL BHT) as a solvent is flowed through the column at a flow rate of 1 mL / min, and components dissolved in o-dichlorobenzene at −15 ° C. are eluted in the TREF column for 10 minutes. Next, the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.

(Iii) Specificity of ethylene content [E] A and [E] B in each component (a) Separation of component (A) and component (B) Based on T (C) determined by the above TREF measurement, Using a temperature-separating column fractionation method using a preparative fractionator, the soluble component (B) in T (C) and the insoluble component (A) in T (C) are fractionated, and the ethylene content of each component is determined by NMR. .
The temperature rising column fractionation method refers to a measurement method disclosed in, for example, Macromolecules, 21 314 to 319 (1988). Specifically, the following method is used in the present invention.
(B) Fractionation conditions A cylindrical column having a diameter of 50 mm and a height of 500 mm is filled with a glass bead carrier (80 to 100 mesh) and maintained at 140 ° C. Next, 200 mL of the o-dichlorobenzene solution (10 mg / mL) of the sample dissolved at 140 ° C. is introduced into the column. Thereafter, the temperature of the column is cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./hour. After holding at 0 ° C. for 1 hour, the column temperature is heated to T (C) at a heating rate of 10 ° C./hour and held for 1 hour. Note that the temperature control accuracy of the column through a series of operations is ± 1 ° C.
Next, while maintaining the column temperature at T (C), 800 mL of o (dichlorobenzene) of T (C) is allowed to flow at a flow rate of 20 mL / min, whereby components soluble in T (C) existing in the column are obtained. Elute and collect.
Next, the column temperature is increased to 140 ° C. at a temperature rising rate of 10 ° C./min, and after leaving still at 140 ° C. for 1 hour, by flowing 800 mL of a 140 ° C. solvent (o-dichlorobenzene) at a flow rate of 20 mL / min, Elute insoluble components with T (C) and collect.
The solution containing the polymer obtained by fractionation is concentrated to 20 mL using an evaporator and then precipitated in 5 times the amount of methanol. The precipitated polymer is recovered by filtration and then dried overnight in a vacuum dryer.
(C) Measurement of ethylene content by ¹³ C-NMR The ethylene content of each of the components (A) and (B) obtained by the above fractionation was measured by a proton complete decoupling method according to the following conditions: ¹³ C-NMR spectrum It is obtained by analyzing.
Model: GSX-400 manufactured by JEOL Ltd. or equivalent equipment (carbon nuclear resonance frequency of 100 MHz or more)
Solvent: o-dichlorobenzene / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / mL
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Integration count: 5,000 times or more The attribution of the spectrum may be performed with reference to, for example, Macromolecules, 17 1950 (1984).
The spectrum assignments measured under the above conditions are as shown in Table 1 below. In Table 1, symbols such as S _αα are in accordance with the notation of Carman et al. (Macromolecules, 10 536 (1977)), P represents a methyl carbon, S represents a methylene carbon, and T represents a methine carbon.

Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six kinds of triads of PPP, PPE, EPE, PEP, PEE, and EEE may exist in the chain. As described in Macromolecules, 15 1150 (1982), the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions (1) to (6).
[PPP] = k × I (T _ββ ) (1)
[PPE] = k × I (T _βδ ) (2)
[EPE] = k × I (T _δδ ) (3)
[PEP] = k × I (S _ββ ) (4)
[PEE] = k × I (S _βδ ) (5)
[EEE] = k × {I (S _δδ ) / 2 + I (S _γδ ) / 4} (6)
Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads. Therefore,
[PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1
... (7)
It is.
Further, k is a constant, I indicates the spectral intensity, and for example, I (T _ββ ) means the intensity of the peak at 28.7 ppm attributed to T _ββ .

By using the relational expressions (1) to (7) above, the fraction of each triad is obtained, and the ethylene content is obtained from the following expression.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100

  In addition, the propylene random copolymer of the present invention contains a small amount of a propylene hetero bond (2,1-bond and / or 1,3-bond), thereby producing the following minute peak.

In order to obtain an accurate ethylene content, it is necessary to include these peaks derived from heterogeneous bonds in the calculation, but it is difficult to completely separate and identify the peaks derived from heterogeneous bonds, and the amount of heterogeneous bonds is small. Therefore, the ethylene content of the present invention is determined using the relational expressions (1) to (7) as in the analysis of the copolymer produced with the Ziegler catalyst that does not substantially contain heterogeneous bonds. .
Conversion from mol% to wt% of ethylene content is carried out using the following formula: ethylene content (wt%) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100) } × 100
Here, X is the ethylene content in mol%.

The ethylene content [E] W of the entire propylene-ethylene random block copolymer is calculated from the ethylene contents [E] A, [E] B and TREF of the components (A) and (B) measured above. From the weight ratios W (A) and W (B)% by weight of the respective components to be calculated, the following formula is used.
[E] W = {[E] A × W (A) + [E] B × W (B) / 100 (% by weight)

(5) Specification by peak of tan δ curve In the present invention, it is necessary that the propylene-ethylene random block copolymer used for the heat-fusible layer is not phase-separated in order to maintain the transparency of the film. However, since the conditions for phase separation are affected not only by the ethylene content but also by the molecular weight and composition, in addition to the above-mentioned regulations regarding ethylene content, the temperature-loss tangent (tan δ) obtained by solid viscoelasticity measurement (DMA) In the curve, it is necessary to define the peak of the tan δ curve.
When the propylene-ethylene random block copolymer has a phase separation structure, the glass transition temperature of the amorphous part contained in the component (A) is different from the glass transition temperature of the amorphous part contained in the component (B). Therefore, there are a plurality of peaks. Conversely, when they are compatible, both components are mixed in the order of molecules and have a single peak at a temperature intermediate between the glass transition temperatures of both components. That is, whether the phase separation structure is taken or not can be discriminated in the temperature-tan δ curve in the solid viscoelasticity measurement. In order to keep the film highly transparent, the tan δ curve has a single peak below 0 ° C. It is necessary to have For example, the propylene-ethylene random block copolymer used in the examples described later has a single peak in the tan δ curve at 0 ° C. or lower, as shown in FIG.

  Specifically, solid viscoelasticity measurement is performed by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece and detecting the generated stress. Here, the frequency is 1 Hz and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured. Further, it is recommended that the magnitude of distortion is about 0.1 to 0.5%. From the obtained stress, the storage elastic modulus G ′ and the loss elastic modulus G ″ are obtained by a known method, and the loss tangent (= loss elastic modulus / storage elastic modulus) defined by this ratio is plotted against the temperature. It shows a sharp peak in the temperature range below 0 ° C. Generally, the peak of the tan δ curve below 0 ° C. is for observing the glass transition of the amorphous part, and here the peak temperature is defined as the glass transition temperature Tg (° C.). Define.

2. Propylene-ethylene random block copolymer production method (i) Metallocene catalyst The method for producing the propylene-ethylene random block copolymer used in the present invention essentially requires the use of a metallocene catalyst.
It is well known to those skilled in the art that stickiness and bleedout deteriorate when the molecular weight and crystallinity distribution are wide in the propylene-ethylene random copolymer, but also in the propylene-ethylene random block copolymer used in the present invention. In order to suppress stickiness and bleed-out, it is necessary to polymerize using a metallocene catalyst that has a narrow molecular weight and crystallinity distribution.
The type of the metallocene-based catalyst is not particularly limited as long as it can produce a copolymer having the performance of the present invention. However, in order to satisfy the requirements of the present invention, for example, the following components ( It is preferable to use a metallocene catalyst comprising a), (b), and component (c) used as necessary.

Component (a): At least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula Component (b): At least one selected from the following (b-1) to (b-4) (B-1) a particulate carrier carrying an organoaluminum oxy compound,
(B-2) Particulate carrier carrying an ionic compound or Lewis acid capable of reacting with component (a) to convert component (a) into a cation (b-3) Solid acid fine particles (b- 4) Ion exchange layered silicate,
Component (c): an organoaluminum compound.

(A) Component As the component (a), at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula can be used.
^{_{Q (C 5 H 4 -aR 1}} ) (C 5 H 4 -bR 2) MeXY
[Wherein Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, Me represents a metal atom selected from titanium, zirconium, and hafnium, and X and Y represent a hydrogen atom, a halogen atom, An atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group is shown, and X and Y may be independently, that is, the same or different. R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group. Show. a and b are the number of substituents. ]

Specifically, Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, and has, for example, a divalent hydrocarbon group, a silylene group, an oligosilylene group, or a hydrocarbon group as a substituent. Examples include a silylene group, an oligosilylene group, or a germylene group having a hydrocarbon group as a substituent. Among these, preferred is a silylene group having a divalent hydrocarbon group and a hydrocarbon group as a substituent.
X and Y represent a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, or a silicon-containing hydrocarbon group. Among these, hydrogen is preferable , Chlorine, methyl, isobutyl, phenyl, dimethylamide, diethylamide group and the like. X and Y may be independent, that is, may be the same or different.
R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group. Represents. Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, and a butadienyl group. In addition, as halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group, methoxy group, ethoxy group, phenoxy group Typical examples include trimethylsilyl group, diethylamino group, diphenylamino group, pyrazolyl group, indolyl group, dimethylphosphino group, diphenylphosphino group, diphenylboron group, and dimethoxyboron group. In these, it is preferable that it is a C1-C20 hydrocarbon group, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, and a butyl group. By the way, adjacent R ¹ and R ² may combine to form a ring, on which a hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing You may have a substituent which consists of a hydrocarbon group, a boron containing hydrocarbon group, or a phosphorus containing hydrocarbon group.
Me is a metal atom selected from titanium, zirconium and hafnium, preferably zirconium and hafnium.

  Among the components (a) described above, those preferred for the production of the propylene-ethylene random block copolymer used in the present invention are crosslinked with a silylene group, a germylene group or an alkylene group having a hydrocarbon substituent. It is a transition metal compound comprising a ligand having a substituted cyclopentadienyl group, a substituted indenyl group, a substituted fluorenyl group, and a substituted azulenyl group, and is particularly preferably crosslinked by a silylene group having a hydrocarbon substituent or a gelmylene group. And a transition metal compound comprising a ligand having a 2,4-position substituted indenyl group and a 2,4-position substituted azulenyl group.

  Non-limiting specific examples include dimethylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, diphenylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, dimethylsilylene bis (2-methyl). Benzoindenyl) zirconium dichloride, dimethylsilylenebis {2-isopropyl-4- (3,5-diisopropylphenyl) indenyl} zirconium dichloride, dimethylsilylenebis (2-propyl-4-phenanthrylindenyl) zirconium dichloride, dimethyl Silylene bis (2-methyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylene bis {2-methyl-4- (4-chlorophenyl) azurenyl} zirconium dichloride, dimethylsilylene bi (2-Ethyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis (2-isopropyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis {2-ethyl-4- (2-fluorobiphenyl) azurenyl} zirconium Examples thereof include dichloride and dimethylsilylenebis {2-ethyl-4- (4-t-butyl-3-chlorophenyl) azurenyl} zirconium dichloride. A compound in which the silylene group of these specific examples is replaced with a germylene group and zirconium is replaced with hafnium is also exemplified as a suitable compound. In addition, since the catalyst component is not an important element of the present invention, it avoids complicated listing and is limited to a representative example, but it is obvious that the effective range of the present invention is not limited thereby. It is.

(B) Component As the component (b), at least one solid component selected from the components (b-1) to (b-4) described above is used. Each of these components is a known component, and can be appropriately selected from known technologies and used. Specific examples and manufacturing methods thereof are described in detail in JP-A No. 2002-284808, JP-A No. 2002-53609, JP-A No. 2002-69116, JP-A No. 2003-105015, and the like.

Here, as the particulate carrier used for the component (b-1) and the component (b-2), inorganic oxides such as silica, alumina, magnesia, silica alumina, silica magnesia, magnesium chloride, magnesium oxychloride, chloride Examples thereof include inorganic halides such as aluminum and lanthanum chloride, and porous organic carriers such as polypropylene, polyethylene, polystyrene, styrene divinyl benzene copolymer, and acrylic acid copolymer.
Further, as a non-limiting specific example of the component (B), a particulate carrier on which methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate tetraisobutyl, etc. are supported as the component (b-1). As component (b-2), triphenylborane, tris (3,5-difluorophenyl) borane, tris (pentafluorophenyl) borane, triphenylcarbonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl Particulate carrier carrying anilinium tetrakis (pentafluorophenyl) borate, etc., component (b-3), alumina, silica alumina, magnesium chloride, etc., component (b-4), montmorillonite, zakonite, beidellite , Nontronic , Saponite, hectorite, stevensite, bentonite, smectite group such as taeniolite, vermiculite, and the like mica group. These may form a mixed layer.
Particularly preferred among the above components (b) is the ion-exchange layered silicate of component (b-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. It is an ion exchange layered silicate applied.

(C) Component As an example of the organoaluminum compound used as the component (c) as necessary, a compound represented by the following general formula is preferable.
AlR _a P _3-a
(Wherein R is a hydrocarbon group having 1 to 20 carbon atoms, P is hydrogen, halogen, alkoxy group, and a is a number of 0 <a ≦ 3)
Specific examples of the compound include trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, and triisobutylaluminum, or halogen- or alkoxy-containing alkylaluminum such as diethylaluminum monochloride and diethylaluminum monomethoxide. In addition, aluminoxanes such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

(Ii) Formation of catalyst Component (a), component (b) and, if necessary, component (c) are brought into contact to form a catalyst. The contact method is not particularly limited, but can be contacted in the following order. Moreover, this contact may be performed not only at the time of catalyst preparation but also at the time of prepolymerization with olefin or at the time of polymerization of olefin.
(B) Contacting component (a) with component (b) (b) Adding component (c) after contacting component (a) with component (b) (c) Component (a) and component (c) ) Is added and then component (b) is added. (D) Component (b) and component (c) are contacted and then component (a) is added.

The amount of components (a), (b) and (c) used in the present invention is arbitrary. For example, the amount of component (a) used relative to component (b) is preferably in the range of 0.1 μmol to 1,000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of component (b). The amount of component (c) used relative to component (b) is preferably such that the amount of transition metal is 0.001 to 100 μmol, particularly preferably 0.005 to 50 μmol, relative to 1 g of component (b). Therefore, the amount of the component (c) to the component (a) is preferably in the range of 10 ⁻⁵ to 50, particularly preferably 10 ^{−4 to} 5 in terms of the molar ratio of the transition metal.

The catalyst used in the present invention is preferably subjected to a prepolymerization treatment consisting of a small amount of polymerization by contacting an olefin in advance. The olefin to be used is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, styrene and the like can be used. It is possible to use, and it is particularly preferable to use propylene. The olefin can be supplied by any method such as a supply method for maintaining the olefin at a constant speed or in a constant pressure state, a combination thereof, or a stepwise change. The prepolymerization temperature and time are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50 with respect to the component (b). After completion of the prepolymerization, the catalyst can be used as it is, depending on the usage form of the catalyst. However, if necessary, drying can be performed.
Furthermore, a polymer such as polyethylene, polypropylene, or polystyrene, or an inorganic oxide solid such as silica or titania can be allowed to coexist during or after the contact of the above components.

(Iii) Polymerization method (a) Sequential polymerization In producing the propylene-ethylene random block copolymer used in the present invention, it is necessary to sequentially polymerize the component (A) and the component (B).
When the propylene-ethylene copolymer is simply a random copolymer obtained by copolymerizing propylene with ethylene, if the ethylene content is low, the flexibility and transparency are not sufficient, and the flexibility and transparency are improved. When the ethylene content is increased, the heat resistance deteriorates, and it is difficult to satisfy all of these.
Therefore, in the present invention, the propylene-ethylene random block copolymer is a block copolymer obtained by sequentially polymerizing components having different ethylene contents in the first step and the second step. Necessary to balance.
In the present invention, since a copolymer having a low molecular weight and easily sticking alone may be used as the component (B), the component (A) is polymerized in order to prevent problems such as adhesion to the reactor. It is necessary to use a method of polymerizing component (B).

When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.
In the case of a batch method, it is possible to polymerize component (A) and component (B) separately using a single reactor by changing the polymerization conditions with time. As long as the effects of the present invention are not impaired, a plurality of reactors may be connected in parallel.
In the case of the continuous process, it is necessary to use a production facility in which two or more reactors are connected in series because it is necessary to individually polymerize the component (A) and the component (B), as long as the effect of the present invention is not impaired. A plurality of reactors may be connected in series and / or in parallel for each of component (A) and component (B).

(B) Polymerization process As the polymerization process, any polymerization method such as a slurry method, a bulk method, or a gas phase method can be used. Although supercritical conditions can be used as intermediate conditions between the bulk method and the gas phase method, they are substantially the same as the gas phase method, and are therefore included in the gas phase method without particular distinction.
Since component (B) is readily soluble in organic solvents such as hydrocarbons and liquefied propylene, it is desirable to use a gas phase method for the production of component (B).
There is no particular problem in using any process for the production of the component (A). However, when producing the component (A) having relatively low crystallinity, a gas phase method is used to avoid problems such as adhesion. It is desirable to use
Therefore, it is most desirable to polymerize component (A) first by the bulk method or gas phase method and then polymerize component (B) by the gas phase method using the continuous method.

(C) Other polymerization conditions The polymerization temperature can be used without any particular problem as long as it is within a commonly used temperature range. Specifically, a range of 0 ° C. to 200 ° C., more preferably 40 ° C. to 100 ° C. can be used.
Although the polymerization pressure varies depending on the process to be selected, it can be used without any problem as long as it is in a pressure range usually used. Specifically, a range of greater than 0 to 200 MPa, more preferably 0.1 to 50 MPa can be used. At this time, an inert gas such as nitrogen may coexist.

  When the component (A) is sequentially polymerized in the first step and the component (B) is sequentially polymerized in the second step, it is desirable to add a polymerization inhibitor to the system in the second step. When producing a propylene-ethylene random block copolymer, adding a polymerization inhibitor to the reactor for carrying out the ethylene-propylene random copolymer in the second step, the particle properties (flowability, etc.) and gel of the resulting powder The product quality can be improved. Various technical studies have been made on this method, and examples thereof include Japanese Patent Publication Nos. 63-54296, 7-25960, and 2003-2939. It is desirable to apply the method to the present invention.

(Vi) Method for controlling constituent elements of propylene-ethylene random block copolymer Each element of the propylene-ethylene random block copolymer used in the present invention is controlled as follows and is necessary for the copolymer of the present invention. It can be manufactured to meet the required configuration requirements.
(I) Component (A)
For component (A), it is necessary to control the ethylene content [E] A and T (A).
In the present invention, in order to control [E] A within a predetermined range, the amount ratio of propylene and ethylene supplied to the polymerization tank in the first step may be appropriately adjusted. The relationship between the supply ratio and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, but the component (A) having the ethylene content [E] A required by adjusting the supply ratio is selected. Can be manufactured.
For example, when [E] A is controlled to 1 to 7% by weight, the supply weight ratio of ethylene to propylene should be in the range of 0.001 to 0.3, preferably in the range of 0.005 to 0.2. That's fine.
At this time, the component (A) has a narrow crystallinity distribution, and T (A) decreases as [E] A increases.
Therefore, in order for T (A) to satisfy the scope of the present invention, [E] A and their relationship are grasped and adjusted so as to take a target range.

(B) Component (B)
For component (B), it is necessary to control the ethylene content [E] B, T (B) and [η] cxs.
In the present invention, in order to control [E] B within a predetermined range, the ratio of ethylene supply to propylene in the second step may be controlled as in [E] A. For example, when [E] B is controlled to 7 to 22% by weight, the supply weight ratio of ethylene to propylene may be in the range of 0.01 to 5, preferably in the range of 0.05 to 2.
At this time, although the crystallinity distribution of the component (B) is slightly increased with the increase of the ethylene content, T (B) is decreased with the increase of [E] B, similarly to the component (A).
Therefore, in order to satisfy T (B) within the scope of the present invention, the relationship between [E] B and T (B) is grasped, and [E] B is controlled to be within a predetermined range. That's fine.

(C) W (A) and W (B)
The amount W (A) of the component (A) and the amount W (B) of the component (B) change the ratio of the production amount of the first step for producing the component (A) and the production amount of the component (B). Can be controlled. For example, in order to increase W (A) and decrease W (B), the production amount of the second step may be reduced while maintaining the production amount of the first step, which shortens the residence time of the second step. It can be easily controlled by lowering the polymerization temperature or increasing the amount of the polymerization inhibitor. The reverse is also true.
When actually setting the conditions, it is necessary to consider the activity decay. That is, in the range of the ethylene content [E] A and [E] B carried out in the present invention, generally, when the ratio of ethylene supply to propylene is increased in order to increase the ethylene content, the polymerization activity increases. The activity decay tends to increase. Therefore, in order to maintain the activity of the second step, it is necessary to suppress the polymerization activity of the first step. Specifically, in the first step, the ethylene content [E] A is lowered and the production amount W (A ), And if necessary, lower the polymerization temperature and / or shorten the polymerization time (residence time), or increase the ethylene content [E] B in the second step and increase the production W (B). If necessary, the conditions may be set by a method that raises the polymerization temperature and / or lengthens the polymerization time (residence time).

(D) Glass transition temperature Tg
The propylene-ethylene random block copolymer used in the present invention has a glass transition temperature Tg, which is a temperature at which a tan δ curve obtained by a temperature-loss tangent curve obtained by solid viscoelasticity measurement shows a peak, and is simply 0 ° C. or less. Need to have one peak. In order for Tg to have a single peak, the difference between the ethylene content [E] A in component (A) and the ethylene content [E] B in component (B) [E] gap (= [E ] B- [E] A) may be 15 wt% or less, preferably 13 wt% or less, and [E] gap may be reduced to a range where Tg becomes a single peak in actual measurement.
According to the ethylene content [E] A in the component (A), the supply amount of ethylene to propylene during the polymerization of the component (B) so that the ethylene content [E] B in the component (B) falls within an appropriate range. By setting the ratio, a propylene-ethylene random block copolymer having a predetermined [E] gap can be obtained.

Moreover, Tg of the propylene-ethylene block copolymer which does not take a phase-separation structure used for this invention is ethylene content [E] A in a component (A), and ethylene content in a component (B) [ E] It is influenced by the quantity ratio of B and both components. In the present invention, the amount of the component (B) is 5 to 70% by weight, but in this range, Tg is more strongly affected by the ethylene content [E] B in the component (B).
That is, Tg reflects the glass transition of the amorphous part, but in the propylene-ethylene block copolymer used in the present invention, the component (A) has crystallinity and relatively few amorphous parts. On the other hand, the component (B) is low crystalline or amorphous and most of it is an amorphous part. Therefore, the value of Tg is almost controlled by [E] B, and the control method of [E] B is as described above.

3. Other compounding agents In addition to the propylene-ethylene random block copolymer, the heat-sealing layer used in the present invention is additionally provided for further property improvement or for other purposes. Ingredients can be added.

As an additional component, for example, butene-1 series polymer or propylene / butene-1 copolymer is added by 5 to 45 parts by weight with respect to 100 parts by weight of the propylene-ethylene random block copolymer. Further, the low temperature heat sealability can be further improved.
Examples of such a butene-1 polymer include a copolymer of butene-1 and other α-olefins such as ethylene and propylene in addition to the butene-1 homopolymer. It is transparent to use a copolymer whose MFR is equal to or greater than the MFR of the propylene-ethylene random block copolymer at the same temperature in the range of 180 to 300 ° C. It is preferable because improvement of

  Further, in order to improve high-speed packaging suitability, it is preferable to add organic lubricants such as various silicone oils and silicone gums. Particularly preferred lubricants include addition of 0.1 to 1 part by weight such as polydiorganosiloxane gum having a degree of polymerization of 3,500 to 8,000 or silicone oil having a viscosity of 100 to 100,000 cst.

Additives such as stabilizers such as antioxidants, neutralizers and weathering agents, processing aids, colorants, antiblocking agents, antistatic agents, lubricants may be added. In particular, those containing an antiblocking agent are preferred. Preferable examples of the anti-blocking agent include organic or inorganic fine particles having an average particle size of 0.5 to 5 μm, preferably 1 to 4 μm. If it is less than 1 μm, the anti-blocking effect is inferior, and if it exceeds 5 μm, transparency deteriorates. A compounding quantity is 0.05 weight part-0.6 weight part with respect to 100 weight part of propylene-ethylene random block copolymers, Preferably it is 0.1-0.5 weight part. If it is less than 0.05 part by weight, the anti-blocking effect is poor, and if it exceeds 0.6 part by weight, transparency deteriorates. Examples of the organic fine particles include non-melting polysiloxane fine particles, polyamide fine particles, acrylic resin fine particles, and condensed fine particles having a triazine ring. Of these, non-melting polysiloxane fine particles and crosslinked polymethyl methacrylate fine particles are preferably used.
Examples of the inorganic fine particles include silica, zeolite, kaolin, and talc. Of these, silica is preferably used.

4). Manufacture of composition for heat-fusion layer Propylene-ethylene random block copolymer is a method of mixing resin pellets by dry blending, Henschel mixer or the like when the number of the polymers is two or more. If the powder is a powder, the powder is blended with the specified additives, mixed in a dry blend, Henschel mixer, etc., then melted and melted at 190 ° C to 350 ° C using a melt kneader, and cut into granules. Can be obtained by a known mixing method such as making a pellet.

  In addition, after measuring the required amount of propylene-ethylene random block copolymer and additional components, it is put into a known mixer such as a Henschel mixer, super mixer, V blender, tumbler mixer, ribbon mixer, Banbury mixer, kneader blender. After mixing, the mixture is further pelletized by melting and kneading at a temperature of 160 to 300 ° C., preferably 180 to 280 ° C., in a known kneader such as a single or twin screw extruder. The method of doing can be mentioned. At this time, the components constituting them may be obtained by mixing at one time, or may be obtained by mixing in advance or mixing into two or more parts or pelletizing.

[3] Heat-Sealable Laminate (1) Lamination The heat-sealable laminate of the present invention is formed from the propylene-ethylene random block copolymer on at least one surface of a polypropylene resin or a base material layer mainly composed of this. As long as the heat-sealing layer is laminated, other layers may be laminated if necessary.
As a method of laminating a base material layer, a heat-sealing layer and other layers as required, a water-cooled inflation molding machine having a plurality of die lips in a plurality of extruders, an air-cooled inflation molding machine, a co-extrusion method using a T-die molding machine Known methods such as a dry laminating method and an extrusion laminating method can be used, but a coextrusion method is particularly preferable.

(2) Stretching The heat-sealable laminate is desirably stretched. Specifically, the heat-sealable laminate is formed into a sheet by melting and coextruding a heat-sealing layer on one side or both sides of the base material layer. None, and a method of biaxially stretching them. This method can be said to be an effective method because it can be easily and uniformly laminated. It can also be formed into a multi-layered tube by the inflation method and then biaxially stretched to form a heat-sealable laminate.
It is also possible to employ a method of biaxially stretching or uniaxially stretching in a direction perpendicular to the stretching direction of the base material layer after the heat-fusible layer is melt extruded onto the unstretched or uniaxially stretched base material layer.
When biaxial stretching is performed by the above method, first, longitudinal stretching can be performed by utilizing the difference in roll peripheral speed between the feed roll and the take-up roll. That is, it is stretched 3 to 8 times, preferably 4 to 6 times at a temperature of 90 to 140 ° C., preferably 105 to 135 ° C., and then 3 to 12 times in a tenter oven in the transverse direction, preferably Stretch 6 to 11 times. In order to prevent thermal shrinkage during heat sealing, it is desirable to heat-set at a temperature of 120 to 170 ° C. following the transverse stretching.

(3) Other treatments The heat-sealable laminate of the present invention can be subjected to surface treatment such as corona treatment for the purpose of promoting printability and bleeding of the antistatic agent.
Moreover, the heat-sealable laminate of the present invention has no particular problem even if any layer is printed to have design properties.

(4) Thickness Although the thickness of the heat-sealable laminate of the present invention is determined according to its use, it is usually in the range of 5 to 100 μm, preferably 10 to 60 μm.
The thickness of the heat-sealing layer used in the heat-sealable laminate of the present invention is generally 0.2-5 μm, preferably 2-4 μm. When the thickness of the heat fusion layer exceeds 4 μm, it may be necessary to modify the film forming equipment. Moreover, when this thickness is less than 2 micrometers, uniform heat seal intensity | strength may not be provided.

(5) Heat-seal strength The heat-seal strength of the heat-sealable laminate of the present invention is determined according to the application, but is usually 800 g / 15 mm or more, preferably 900 g / 15 mm or more. If the heat seal strength is less than 800 g / 15 mm, the bag may be broken during packaging or transportation, which is not preferable.
Here, the heat seal strength is set at a temperature of 120 ° C. to 5 ° C. for each heat seal bar, and at each temperature, the film is melt extruded under the conditions of a heat seal pressure of 0.1 MPa and a heat seal time of 1 second. Measured by taking a 15mm wide sample from the sample sealed so as to be perpendicular to the measured direction (MD direction), pulling it off in the MD direction at a tensile speed of 500mm / min using a shopper type tester, and reading the load The value to be

(6) Sum of tensile modulus (MD + TD)
In the heat-sealable laminate of the present invention, the sum of the tensile modulus in the flow direction (MD) of the laminate and the tensile modulus in the direction (TD) perpendicular to the flow direction is preferably 4000 MPa or more, more preferably Is in the range of 4500 MPa or more. When the sum of the tensile elastic moduli is less than 4000 MPa, the film becomes weak and the suitability for an automatic packaging machine may deteriorate.
Here, the tensile elastic modulus is a value measured according to JISK7127.

(7) Use of heat-sealable laminate The heat-sealable laminate of the present invention can be easily manufactured with conventional equipment, and has sufficient heat-seal strength and high tensile elastic modulus to package heavy objects. Therefore, it can be used for various packaging bodies, and in particular, can be suitably used for packaging applications such as foods, clothing, medicines, stationery, and miscellaneous goods.
Specific examples of the package using the heat-sealable laminate of the present invention include fruits and vegetables, frozen foods, Japanese / Western confectionery, and other food packages.

In order to describe the present invention more specifically, examples and comparative examples will be described below. However, in order to clarify the present invention, preferred examples are described. Of course, the invention is not limited in any way by these examples.
The measuring methods of various physical properties used in the following Examples and Comparative Examples and the resins used are as follows.

1. Measurement method of physical properties (1) TREF
The TREF measurement method was performed as described above using the following apparatus.
(I) TREF section TREF column: 4.3 mmφ × 150 mm stainless steel column Column packing material: 100 μm Surface inactive glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000 (Valve Oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve (ii) Sample injection part Injection method: Loop injection method Injection amount: Loop size 0.1ml
Inlet heating method: Aluminum heat block Measurement temperature: 140 ° C
(Iii) Detection unit Detector: Fixed wavelength infrared detector MIRAN 1A manufactured by FOXBORO
Detection wavelength: 3.42 μm
High-temperature flow cell: Micro flow cell for LC-IR Optical path length 1.5mm Window shape 2φ x 4mm oval Synthetic sapphire window Measurement temperature: 140 ° C
(Iv) Pump unit Liquid feed pump: SSC-3461 pump manufactured by Senshu Kagaku Co. (v) Measurement conditions Solvent: o-dichlorobenzene (including 0.5 mg / mL BHT)
Sample concentration: 5 mg / mL
Sample injection volume: 0.1 mL
Solvent flow rate: 1 mL / min (2) Measurement of solid viscoelasticity A sample cut into a strip of 10 mm width × 18 mm length × 2 mm thickness from a 2 mm thick sheet injection molded under the following conditions was used. The apparatus used was ARES manufactured by Rheometric Scientific. The frequency is 1 Hz. The measurement temperature was raised stepwise from −60 ° C., and the measurement was performed until the sample melted and became impossible to measure. The strain was performed in the range of 0.1 to 0.5%.
Standard number: JIS K-7152 (ISO 294-1) reference Molding machine: EC20P injection molding machine manufactured by Toshiba Machine Co., Ltd. Molding machine set temperature: (from under the hopper) 80, 210, 210, 200, 200 ° C.
Mold temperature: 40 ℃
Injection speed: 52 mm / s (screw speed)
Holding pressure: 30 MPa
Holding time: 8 seconds
Mold shape: flat plate (thickness 2mm, width 40mm, length 80mm)
(3) Calculation of each component amount It calculated by the method mentioned above using TREF.
(4) Calculation of ethylene content It calculated by the method mentioned above using NMR.
(5) Peak of tan δ curve It was measured by intrinsic viscoelasticity measurement.
(6) Heat-seal strength The heat-seal strength of the heat-sealable laminate of the present invention is set at a temperature of 120 ° C. to 5 ° C. for each heat seal bar. A sample having a width of 15 mm is taken from a sample sealed so as to be perpendicular to the direction of melt extrusion of the film (MD direction) under the condition of 1 second for time, and MD is drawn at a tensile speed of 500 mm / min using a shopper type tester. The measurement was performed by pulling away in the direction and reading the load. Of the heat seal strengths measured at each heat seal temperature, the maximum value of the heat seal strength was taken as the heat seal strength of the film.
(7) Tensile Elastic Modulus According to JIS K7127, the tensile elastic modulus in the film flow direction (MD) and the film flow orthogonal direction (TD) was measured. The measurement was performed 5 times in each direction, and the average value was taken as the tensile modulus of elasticity in each direction.

2. Resin used As the propylene-ethylene random block copolymer, the propylene-ethylene random block copolymer (A-1) obtained in the following Production Example 1 was used, and as a resin constituting each layer, a commercially available propylene-based heavy polymer was used. Copolymers (B-1) to (B-4), propylene-ethylene-butene random copolymer (C-1), and petroleum resins (D-1) to (D-2) were used.

(1) Propylene-ethylene random block copolymer (Production Example 1)
(I) Preparation of prepolymerization catalyst (a) Chemical treatment of silicate In a 10-liter glass separable flask equipped with a stirring blade, 3.75 liters of distilled water and then 2.5 kg of concentrated sulfuric acid (96%) were added. Slowly added. At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm distribution, particle size = 10-60 μm) was dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake, and after reslurry, it was filtered. This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.
(B) Drying of silicate The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical inner diameter 50 mm Heating zone 550 mm (Electric furnace) Revolving speed with lifting blade: 2 rpm Tilt angle 20/520 Silicate feed rate: 2.5 g / min Gas flow rate: Nitrogen 96 liters / hour Countercurrent drying temperature : 200 ° C (powder temperature)
(C) Preparation of catalyst 20 g of dry silicate was introduced into a glass reactor with an internal volume of 1 liter, and 116 ml of mixed heptane and 84 ml of a heptane solution of triethylaluminum (0.60M) were added at room temperature. Stir. After 1 hour, the mixture was washed with mixed heptane, and the silicate slurry was adjusted to 200 ml. Next, 0.96 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. In parallel, 218 mg (0.3 mM) of [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium] in 87 ml of mixed heptane Then, 3.31 ml of a heptane solution of triisobutylaluminum (0.71 M) was added, and the mixture reacted at room temperature for 1 hour was added to the silicate slurry. After stirring for 1 hour, the mixture was adjusted to 500 ml by adding mixed heptane. .
(D) Preliminary polymerization / washing Subsequently, the silicate / metallocene complex slurry prepared previously was introduced into a stirring command autoclave having an internal volume of 1.0 liter sufficiently substituted with nitrogen. When the temperature was stabilized at 40 ° C., propylene was supplied at a rate of 10 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the remaining monomer was purged, the stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted. Subsequently, 0.95 ml of a heptane solution of triisobutylaluminum (0.71 M / L) and 560 ml of mixed heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then 560 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the last supernatant liquid was carried out, 17.0 ml of a heptane solution having an organoaluminum component concentration of 1.23 M / L) was added, followed by drying at 45 ° C. under reduced pressure. A prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.
(The above catalyst adjustment was performed by the method described in Example 1 of JP-A-2002-284808.)
Using this prepolymerized catalyst, a propylene-ethylene random block copolymer was produced according to the following procedure.

(Ii) Polymerization (b) First step (Production of component (A)) After sufficiently replacing an autoclave having an internal volume of 3 L having a stirring and temperature control device with propylene, 2.76 ml of triisobutylaluminum / n-heptane solution ( 2.02 mmol), 150 ml of hydrogen, 18 g of ethylene, and then 750 g of liquid propylene were introduced, and the temperature was maintained by raising the temperature to 70 ° C. The prepolymerized catalyst was slurried with n-heptane as a catalyst ( The polymerization was started by injecting 10 mg (excluding the weight of the prepolymerized polymer), and the polymerization was continued for 15 minutes while maintaining the internal temperature at 70 ° C. Thereafter, the residual monomer was purged to normal pressure, and further purified nitrogen was used. A portion of the polymer produced (17.2 g) was sampled and analyzed and found to have an ethylene content of 1.75% by weight, M FR was 9.8 g / 10 min.
(B) Second step (Manufacture of component (B) Separately, a mixed gas used in the second step was adjusted using an autoclave with an internal volume of 20 L having a stirring and temperature control device. The adjusted temperature was 80 ° C., mixing The gas composition was 31.2 vol% ethylene, 68.8 vol% propylene, and 100 volppm hydrogen, and this mixed gas was supplied to a 3 L autoclave to start polymerization in the second step, at a polymerization temperature of 80 ° C. and a pressure of 2. Polymerization was continued for 60 minutes at 0 MPa G. Thereafter, 10 ml of ethanol was introduced to terminate the polymerization, and the recovered polymer was sufficiently dried in an oven to produce a powdery propylene-ethylene random block copolymer (A-1). Got.
The yield of the obtained propylene-ethylene random block copolymer was 379 g, the activity was 40.9 kg / g-catalyst, the ethylene content was 5.6% by weight, and the MFR was 5.9 g / 10 min.
The block copolymer has an ethylene content of component (A) of 1.75% by weight, a composition ratio of 58% by weight, an ethylene content of component (B) of 10.9% by weight, a composition ratio of 42% by weight, and a tan δ curve. It had a single peak at −9 ° C. (see FIG. 3).
(C) Pelletization The above polymerization was repeated to produce at least 2 kg of polymerized powder. Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane was added to the obtained powdery propylene-ethylene random block copolymer as an antioxidant. 500 ppm and 500 ppm tris (2,4-di-t-butylphenyl) phosphite, 500 ppm calcium stearate as a neutralizing agent, 2000 ppm polymethyl methacrylate fine particles having an average particle diameter of 2 μm as an antiblocking agent, After sufficiently stirring and mixing using a Henschel mixer, the mixture is melt-kneaded under the following conditions, the molten resin extruded from the strand die is taken out while being cooled and solidified in a cooling water tank, and the strand is about 2 mm in diameter using a strand cutter. A pellet-shaped plug is cut by cutting to about 3 mm in length. Pyrene - give ethylene random block copolymer (A-1).
Extruder: Technobel KZW-15-45-MG twin screw extruder
Screw: 15mm caliber L / D45
Extruder set temperature: 40, 80, 160, 200, 220, 220 (die) ° C. from below the hopper
Screw rotation speed: 400rpm
Discharge amount: Adjusted to 1.5 kg / h with a screw feeder Die: 3 mm diameter strand die 2 holes

(2) Propylene polymer (i) Propylene polymer (B-1): Nippon Polypro Co., Ltd. trade name Novatec “F203T”, MFR: 2.3 g / 10 min, melting point: 158 ° C.
(Ii) Propylene polymer (B-2): Nippon Polypro Co., Ltd. trade name Novatec “FL6H”, MFR: 3.0 g / 10 min, melting point: 160 ° C.
(Iii) Propylene polymer (B-3): Nippon Polypro Co., Ltd. trade name Novatec “FL1175NB”, MFR: 3.2 g / 10 min, melting point: 160 ° C.
(Iv) Propylene polymer (B-4): trade name “FY6H” manufactured by Nippon Polypro Co., Ltd., MFR: 1.8 g / 10 min, melting point: 165 ° C.
(V) Propylene-ethylene-butene random copolymer (C-1): Nippon Polypro Co., Ltd. trade name Novatec “FX4E”, MFR: 5.5 g / 10 min, melting point: 133 ° C.
(3) Petroleum resin (i) Petroleum resin (D-1): Trade name Alcon “P90” manufactured by Arakawa Chemical Industries, Ltd., softening point: 90 ° C.
(Ii) Petroleum resin (D-2): Product name Opera “PR103J” manufactured by ExxonMobil Co., Ltd., softening point: 125 ° C.

Example 1
The propylene-ethylene random block copolymer (A-1) is used as a heat-sealing layer, the propylene-based polymer (B-1) is 75% by weight, and the propylene-ethylene-butene random copolymer (C-1) is used. Using a resin mixture of 25% by weight as the base material layer, two extruders each having two independent layers so that the thickness ratio of the base material layer / heat fusion layer is 9/1, and contact with this Using the two-layer T die method film production apparatus equipped with the two-layer T die, the cooling roll, and the air knife, the melted two-layer co-extruded so that the heat-sealing layer surface is in contact with the cooling roll at an extrusion resin temperature of 230 ° C. After that, a co-extruded laminate was obtained by co-extrusion with a chill roll at a cooling roll temperature of 20 ° C. at a film forming take-up speed of 3 m / min. Heat seal with a layer thickness of 18μm / 2μm To obtain a laminate. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 2)
The resin mixture used for the base material layer was replaced with a resin mixture consisting of 90% by weight of the propylene polymer (B-1) and 10% by weight of the propylene-ethylene random block copolymer (A-1). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 3)
The resin mixture used for the base material layer was replaced with a resin mixture composed of 70% by weight of the propylene polymer (B-1) and 30% by weight of the propylene-ethylene random block copolymer (A-1). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

Example 4
Except having replaced the resin mixture used for the base material layer with the resin mixture which consists of 20 weight% of propylene-type polymers (B-1), and 80 weight% of propylene-type polymers (B-2), Example 1 to obtain a heat-sealable laminate. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 5)
The resin mixture used for the base material layer was replaced with a resin mixture composed of 30% by weight of propylene-ethylene random block copolymer (C-1) and 70% by weight of propylene-based polymer (B-2). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 6)
The resin mixture used for the base material layer was replaced with a resin mixture consisting of 15% by weight of the propylene-ethylene random block copolymer (C-1) and 85% by weight of the propylene-based polymer (B-2). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 7)
The resin mixture used for the base material layer was replaced with a resin mixture consisting of 10% by weight of propylene-ethylene random block copolymer (D-1) and 90% by weight of propylene-based polymer (B-3). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 8)
The resin mixture used for the base material layer was replaced with a resin mixture consisting of 10% by weight of propylene-ethylene random block copolymer (D-2) and 90% by weight of propylene-based polymer (B-3). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

Example 9
The resin mixture used for the base material layer was composed of 10% by weight of petroleum resin (D-2), 60% by weight of propylene polymer (B-3) and propylene-ethylene random block copolymer (A-1). A heat-sealable laminate was obtained in accordance with Example 1 except that the resin mixture was changed to 30% by weight. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 10)
The resin mixture used for the base material layer was composed of 20% by weight of petroleum resin (D-2), 50% by weight of propylene polymer (B-3) and propylene-ethylene random block copolymer (A-1). A heat-sealable laminate was obtained in accordance with Example 1 except that the resin mixture was changed to 30% by weight. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Example 11)
The resin mixture used for the base material layer was replaced with a resin mixture composed of 80% by weight of the propylene polymer (B-3) and 20% by weight of the propylene-ethylene random block copolymer (A-1). Obtained a heat-sealable laminate in accordance with Example 1. The test results are shown in Table 3. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength, and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (the plot is ◆).

(Comparative Example 1)
A heat-sealable laminate was obtained in accordance with Example 1 except that the resin mixture used for the base material layer was replaced with a propylene polymer (B-4). The test results are shown in Table 4. In addition, the relationship between ΔHm of the base resin and the heat seal strength is plotted in FIG. 1 (plot is ◆), and the relationship between the tensile modulus and the heat seal strength is plotted in FIG. 2 (plot is ▲).

(Comparative Example 2)
A heat-sealable laminate was obtained in accordance with Example 1 except that the resin mixture used for the base material layer was replaced with the propylene polymer (B-1). The test results are shown in Table 4. In addition, the relationship between ΔHm of the base resin and the heat seal strength is plotted in FIG. 1 (plot is ◆), and the relationship between the tensile modulus and the heat seal strength is plotted in FIG. 2 (plot is ▲).

(Comparative Example 3)
A heat-sealable laminate was obtained in accordance with Example 1 except that the resin mixture used for the base material layer was replaced with a propylene polymer (B-3). The test results are shown in Table 4. In addition, the relationship between ΔHm of the base resin and the heat seal strength is plotted in FIG. 1 (plot is ◆), and the relationship between the tensile modulus and the heat seal strength is plotted in FIG. 2 (plot is ▲).

(Comparative Example 4)
The propylene-ethylene random block copolymer (A-1) used for the heat-fusible layer, the propylene-ethylene random block copolymer (C-1), the resin mixture used for the base material layer, the propylene-based heavy polymer A heat-sealable laminate was obtained in accordance with Example 1 except that it was replaced with the coalescence (B-1). The test results are shown in Table 4. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength (plot is ▲), and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (plot is ▲).

(Comparative Example 5)
The propylene-ethylene random block copolymer (A-1) used for the heat-fusible layer, the propylene-ethylene random block copolymer (C-1), the resin mixture used for the base material layer, the propylene-based heavy polymer Heat-sealable lamination according to Example 1 except that the resin mixture comprising 75% by weight of the blend (B-1) and 25% by weight of the propylene-ethylene random block copolymer (C-1) was replaced. Got the body. The test results are shown in Table 4. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength (plot is ▲), and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (plot is ▲).

(Comparative Example 6)
The propylene-ethylene random block copolymer (A-1) used for the heat-fusible layer, the propylene-ethylene random block copolymer (C-1), the resin mixture used for the base material layer, the propylene-based heavy polymer A heat-sealable laminate was obtained in accordance with Example 1 except that the resin mixture consisting of 25% by weight of the union (B-1) and 75% by weight of the propylene polymer (B-2) was replaced. . The test results are shown in Table 4. Further, FIG. 1 plots the relationship between ΔHm of the base resin and the heat seal strength (plot is ▲), and FIG. 2 plots the relationship between the tensile elastic modulus and the heat seal strength (plot is ▲).

  As is apparent from Tables 3 and 4, Examples 1 to 11 are heat-sealable laminates that satisfy all the constituent requirements of the present invention, and therefore have sufficiently high heat-seal strength for packaging heavy objects. It can be seen that it is well above 800 g / 15 mm and has an excellent balance between tensile modulus and heat seal strength. This is evident from Examples 1 to 11 (plot is ◆) plotted in FIG. On the other hand, as is clear from Comparative Examples 1 to 6 plotted in FIG. 2 (the plot is ▲), the heat-sealable laminate that deviates from the specification of the present invention has a low level of relationship between tensile elastic modulus and heat-seal strength. Is in balance.

Moreover, when the propylene-ethylene random block copolymer of the present invention is used for the heat-sealing layer, ΔHm of the polypropylene resin composition used for the base material layer and the heat seal strength of the resulting heat-sealable laminate are obtained. It is clear from Examples 1 to 11 and Comparative Examples 1 to 3 (plotted are ◆) plotted in FIG. 1 that the proportional relationship is established. On the other hand, if the specific propylene-ethylene random block copolymer of the present invention is not used for the heat-fusible layer, as is clear from Comparative Examples 4 to 6 (plot is ▲) plotted in FIG. There is no proportional relationship between ΔHm of the polypropylene resin composition used for the base material layer and the heat seal strength of the resulting heat sealable laminate, and the heat seal strength is also low. About Comparative Examples 1-3, since (DELTA) Hm of a base material layer has remove | deviated from the structural requirement of this invention, the heat seal intensity | strength which a heat sealing | fusion layer has cannot fully be expressed. Comparative Example 4 is a heat-sealable laminate composed of a heat-sealing layer that deviates from the structural requirements of the present invention, and ΔHm of the base material layer deviates from the structural requirements of the present invention. The strength is very poor. Since Comparative Examples 5 and 6 are heat-sealable laminates composed of a heat-sealing layer that deviates from the structural requirements of the present invention, the heat seal is achieved although ΔHm of the base material layer satisfies the structural requirements of the present invention. The strength has become very inferior.
As described above, in order to improve the heat seal strength of the heat-sealable laminate, it is not sufficient to simply consider the heat-sealing layer, and a synergistic effect with the base material layer must be taken into consideration. Don't be.
The present invention has succeeded in providing an excellent synergistic effect by specifying the resin used for the heat-fusible layer and the resin used for the base material layer, and has an unprecedented excellent heat seal strength and tensile elastic modulus. In addition to being able to obtain a heat-sealable laminate having a balance and a package using the same, a method was also established that can assume heat-seal strength at the resin design stage.

  The heat-sealable laminate of the present invention can be easily manufactured with conventional equipment, and has sufficient heat-seal strength and high tensile elastic modulus for packaging heavy objects, so it can be used for various packagings. In particular, it can be suitably used for packaging applications such as food, clothing, medicine, stationery, and miscellaneous goods.

It is a graph which shows the relationship between (DELTA) Hm of a base material layer, and heat seal intensity | strength. It is a graph which shows the relationship between a tensile elasticity modulus and heat seal strength. It is a figure which shows the temperature-tan-delta curve etc. in a solid viscoelasticity measurement. It is a figure which shows the elution amount by a temperature rising elution fractionation method (TREF), and elution amount integration | stacking.

Claims (7)

Propylene-ethylene random block co-polymer satisfying the following conditions (i) to (ii) obtained by using a metallocene-based catalyst for a laminate comprising a heat-fusible layer and a base material layer A heat-sealable laminate comprising a polypropylene resin composition having a ΔHm (heat of fusion) measured in accordance with JIS K7122 of 50 to 96 mJ / mg. .
(I) 30 to 70% by weight of the propylene-ethylene random copolymer component (A) having an ethylene content of 1 to 7% by weight in the first step, and then 6 to 15% by weight of the component (A) in the second step. % Propylene-ethylene random copolymer component (B) containing a large amount of ethylene is successively polymerized in an amount of 70 to 30% by weight. (Ii) In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve is 0 ° C. or less. Have a single peak   The heat sealable laminate according to claim 1, wherein the heat seal strength is 900 g / 15 mm or more.   The heat-sealable laminate according to claim 1 or 2, wherein the heat-sealing layer has a thickness of 2 to 4 µm.   The sum of the tensile elastic modulus in the flow direction (MD) of the laminate measured in accordance with JISK 7127 and the tensile elastic modulus in the direction (TD) perpendicular to the flow direction is 4000 MPa or more. The heat-sealable laminated body of any one of 1-3.   The heat-sealable laminate according to any one of claims 1 to 4, wherein the polypropylene resin composition used in the base material layer is composed of two or more types of polypropylene resins. .   The heat-sealable laminate according to any one of claims 1 to 5, wherein a petroleum resin is blended in the polypropylene resin composition used for the base material layer.   The package which uses the heat-sealable laminated body described in any one of Claims 1-6.

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