JP2000255012A - Multilayered laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate reduced in the lowering of heat seal strength due to heat sterilization, excellent in low temp. impact strength and whitening resistance and suitably used as a packaging material. SOLUTION: A multilayered laminate comprises at least three layers, that is, both outer layers each comprising a propylene/α-olefin block copolymer consisting of 95-70 wt.% of a polypropylene block and 5-30 wt.% of a copolymer elastomer block of propylene and a 2-12C (excepting 3C) α-olefin and an intermediate layer comprising a propylene polymer compsn. having a main crystallizing peak temp. of 105-110 deg.C, a sub-crystallizing peak temp. (Tcp2) of 65-85 deg.C and a ratio of a sub-crystallizing peak area to a main crystallizing peak area of at most 4.0% or less and 10-30 wt.% of a xylene soluble component (XI) satisfying Tcp2<=-1.05XI+104.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer laminate comprising a propylene-.alpha.-olefin block copolymer and a specific propylene-based polymer composition. More specifically, it is suitable for use as a heat seal layer of a packaging material. It has a small decrease in heat seal strength due to heat sterilization by retort sterilization, etc., has excellent low-temperature impact strength and whitening resistance, and has a small amount of blemishes during molding. The present invention relates to a multilayer laminate suitable as a food packaging material and a medical packaging material having excellent properties.

[0002]

2. Description of the Related Art Hitherto, polypropylene films have been used as various food packaging materials and various medical packaging materials by making use of features such as low cost, heat resistance, chemical resistance and easy heat sealing. In the food packaging field, packaging materials such as retort food, aluminum foil or vinylidene chloride resin or a saponified ethylene-vinyl acetate copolymer resin as a gas barrier layer, combined with a polyamide resin layer and a polyester resin layer, etc. A multilayer film in which polypropylene is laminated is used as a heat seal layer. Also, in the field of medical packaging materials, polypropylene is used as a heat seal layer. In food packaging, after filling the contents, heat sterilization such as boil sterilization and retort sterilization is performed, and storage at room temperature or at low temperature is performed. Among the polypropylenes used as the heat seal layer, homopolypropylene has a problem in that it has poor impact resistance and cannot withstand low-temperature storage. In addition, even an ethylene-propylene random copolymer having better impact strength than homopolypropylene does not have satisfactory low-temperature impact strength, and also has a problem that the films adhere to each other or deform when heated and sterilized. Therefore, as a polypropylene film for retort foods, a film formed by blending a thermoplastic elastomer component with a propylene block copolymer or an ethylene-propylene random copolymer (for example, JP-B-6-86109, JP-A-7-26037) JP, JP-A-7-166024, JP-A-8-302110, JP-A-10-15
No. 2596) has been proposed.

[0003]

However, when heat sterilization such as retort sterilization is performed, the heat sealing strength after heating is still insufficient. INDUSTRIAL APPLICABILITY The present invention is a food packaging material and a medical packaging material having a small decrease in heat seal strength due to heat sterilization due to retort sterilization treatment, low temperature impact strength, excellent whitening resistance, and excellent productivity with little occurrence of eyes and eyes. An object is to provide a suitable multilayer laminate.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object can be achieved by forming a specific propylene-α-olefin block copolymer as an intermediate layer into multiple layers. The present inventors have completed the present invention based on this finding. That is, the present invention
(A) (a) 95 to 70% by weight of a polypropylene block, (b) propylene and 2 to 12 carbon atoms (however,
(B) an outer layer composed of a propylene-α-olefin block copolymer composed of 5 to 30% by weight;
(1) A crystallization temperature curve measured using a differential scanning calorimeter has a main crystallization peak temperature (T _CP1 ) at a temperature of 105 to 110 ° C. and a secondary crystallization peak at a temperature of 65 to 85 ° C. Secondary crystallization peak area (T _CA2 ) having temperature (T _CP2 ) and with respect to main crystallization peak area (T _CA1 )
Is at most 4.0% or less,
(2) The xylene-soluble component (XI) at a temperature of 25 ° C. is 1
(3) the secondary crystallization peak temperature (T _CP2 ) and the xylene solubles (X
Provided is a multilayer laminate comprising at least three layers including an intermediate layer composed of a propylene-based polymer composition that satisfies the formula: T _CP2 ≦ −1.05 XI + 104 with respect to I).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Propylene-α- in the present invention
The olefin block copolymer (hereinafter may be abbreviated as “component (A)”) comprises (a) polypropylene block 95 to
70% by weight, and (b) a copolymer of propylene and an α-olefin having 2 to 12 (excluding 3) carbon atoms, which is mainly composed of an elastomer block. (A)
Examples of the polypropylene block include homopolypropylene or a random copolymer of propylene and 5% by weight or less of an α-olefin having 2 to 14 carbon atoms (excluding 3). The copolymerization ratio of the α-olefin is preferably 4.5% by weight or less, more preferably 4.0% by weight or less. If the copolymerization ratio is more than 5% by weight, rigidity and heat resistance are impaired, and low crystallinity components are increased, resulting in undesired cohesion of the film.

[0006] (b) As the elastomer block, propylene and C2-12 (excluding 3) are used.
And a copolymerization ratio of the α-olefin is 5 to 40% by weight, preferably 10 to 35% by weight, particularly preferably 15 to 30% by weight. is there. The copolymerization ratio of the component (b) in the component (A) is 5 to 30% by weight.
It is preferably from 28 to 28% by weight, and particularly preferably from 15 to 25% by weight. If the copolymerization ratio is less than 5% by weight, the heat seal strength after the retort sterilization treatment is greatly reduced, and the impact resistance and the cold resistance are poor. On the other hand, if it exceeds 30% by weight, there is a problem that the heat resistance is inferior and the films adhere to each other by heat sterilization such as retort treatment.

The above-mentioned α-olefins include 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene and 4,4-dimethyl-1
-Pentene, vinylcyclopentane, vinylcyclohexane and the like. These α-olefins may be used alone or in combination of two or more.
Melt flow rate of component (A) (MFR; JIS K7)
210, under the conditions of a temperature of 230 ° C. and a load of 2.16 Kg), and is not particularly limited, and is selected by a molding method. For example, when used in a T-die molding method, it is usually 0.5 to 5 g / 10. Minutes, preferably 0.8-4 g
/ 10 minutes, particularly preferably 1.0 to 3 g / 10 minutes. If the MFR is less than 0.5 g / 10 minutes, the blemishes are likely to occur during molding, and the productivity is poor, which is not preferable. 5
If it exceeds g / 10 minutes, the impact strength and the compatibility with the intermediate layer described later are inferior, and the degree of reduction in heat seal strength after retort sterilization tends to be large, which is not preferable.

The propylene-based polymer composition (hereinafter sometimes abbreviated as “component (B)”) according to the present invention has the following properties: (1) a crystallization temperature curve measured by a differential scanning calorimeter; Main crystallization peak temperature (T
_CP1 ), a secondary crystallization peak temperature (T _CP2 ) at a temperature of 65 to 85 ° C., and a main crystallization peak area (T _CP2 ).
The ratio (AR) of the secondary crystallization peak area (T _CA2 ) to the _{CA 1} ) is at most 4.0% or less, and (2) the xylene solubles (XI) at a temperature of 25 ° C. are 10 to 30.
(3) Secondary crystallization peak temperature (T _CP2 )
And the xylene-soluble component (XI) at a temperature of 25 ° C. satisfies the formula: T _CP2 ≦ −1.05 XI + 104.

The above-mentioned crystallization temperature curve is based on JIS K712.
2 and is measured in accordance with DSC,
This is a method of quantifying a thermal change that occurs when a sample is cooled at a constant rate as a thermal energy amount. In particular,
After dissolving about 2 to 5 mg of a sample at 230 ° C. for 5 minutes,
It is obtained by lowering the temperature to −30 ° C. at a rate of minutes.
T _CP1 measured in this way is from 105.5 to 109
C is preferable, and 106 to 108 C is particularly preferable. T
_{When CP1} is less than 105 ° C., the crystallization speed is slow, the solidification during molding is slow, the moldability is poor, the flow of the molded product is uneven, and the heat seal strength after heat sterilization is poor. On the other hand, when it exceeds 110 ° C., radiation resistance, flexibility, cold resistance and heat seal strength after heat sterilization are inferior. Also, T
_CP2 is preferably from 66 to 83C, more preferably from 68 to 83C. If _TCP2 is _lower than 65 ° C, the rigidity and heat resistance are poor. On the other hand, if the temperature exceeds 85 ° C., radiation resistance, cold resistance, and heat sealing strength after heat sterilization are inferior, so that it is not preferable. In the component (B) of the present invention, the ratio (AR) of the secondary crystallization peak area (hereinafter, “T _CA2 ”) to the main crystallization peak area (hereinafter, “T _CA1 ”) is preferably 3.8% or less. In particular, 3.5% or less is preferable. AR is 4.
If it exceeds 0%, radiation resistance, cold resistance and heat seal strength after heat sterilization are inferior. On the other hand, the lower limit is not particularly limited, but is preferably 0.1% or more.

[0010] (2) The xylene-soluble matter at 25 ° C (hereinafter referred to as “X1”) is the soluble matter obtained by dissolving about 1% by weight of a sample in ortho-xylene at a temperature of 130 ° C and then cooling to 25 ° C. And the component (B) of the present invention is 10 to 3
0% by weight, preferably 15 to 29% by weight, particularly preferably 20 to 27% by weight. When X1 is less than 10% by weight, impact resistance and radiation resistance are poor. On the other hand, if it exceeds 30% by weight, heat resistance and rigidity are inferior.
The relationship between T _CP2 and XI is _expressed by the following equation: T _CP2 ≦ −1.
It is necessary to satisfy 05XI + 104. If the above formula is not satisfied, the heat seal strength after heat sterilization is greatly reduced, which is not preferable. The above equation is preferably T _CP2 ≦ −1.1
8XI + 106, particularly preferably T _CP2 ≦ −
1.31 XI + 108.

The component (B) satisfying the above conditions includes:
(A) (a) 95 to 70% by weight of a polypropylene block, (b) propylene and 2 to 12 carbon atoms (however,
Propylene-α-olefin block copolymer composed of 5 to 30% by weight of α-olefin and 60 to 95% by weight of (C)
(A) 60 to 30% by weight of a polypropylene block;
(B) Copolymer elastomer block of propylene and α-olefin having 2 to 12 carbon atoms (excluding 3) A soft propylene-α-olefin block copolymer composed of 40 to 70% by weight (hereinafter referred to as “(C ) Component) (may be abbreviated as "component").

The propylene-α-olefin block copolymer of the component (B) is the same polymer as the component (A). The α-olefin is also the same as described above.
As the (a) polypropylene block of the component (C),
Copolymers of propylene and other α-olefins having 12 or less carbon atoms can be mentioned, and the copolymerization ratio of the other α-olefin is 8.0% by weight or more, preferably 9.0% by weight.
Above, particularly preferably 10% by weight or more. If the copolymerization ratio is less than 8% by weight, rigidity and heat resistance are impaired, and heat seal strength is greatly reduced by heat sterilization, which is not preferable. Examples of the propylene block copolymer elastomer (b) include a copolymer elastomer of propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3), and a copolymerization ratio of the α-olefin. Is 30
８０80% by weight, preferably 35-75% by weight, particularly preferably 38-72% by weight. Copolymerization ratio is 3
If it is less than 0% by weight, impact resistance and cold resistance are poor. On the other hand, 80
Exceeding the weight% is not preferred because heat resistance is impaired. The copolymerization ratio of the elastomer block (b) in the component (C) is 40 to 70% by weight, preferably 4 to 70% by weight.
It is 5 to 69% by weight, particularly preferably 50 to 68% by weight. If the copolymerization ratio is less than 40% by weight, the impact resistance,
The deterioration of heat resistance after cold sterilization and heat sterilization is significantly inferior. On the other hand, if it exceeds 70% by weight, rigidity and retort aptitude such as mutual adhesion of films are inferior, so that it is not preferable. The proportion of the component (C) in the component (B) of the present invention is 5-4.
0% by weight, preferably 8 to 35% by weight, more preferably 10 to 30% by weight. (C) Component ratio is 5
If it is less than the weight percentage, the effect of improving the heat seal strength after heat sterilization is poor. On the other hand, if it exceeds 40% by weight, heat resistance, rigidity and chemical resistance are inferior, so that it is not preferable.

Further, when the blending method is used, the component (C) having excellent physical properties includes the following (a) and (b)
Those having the following characteristics are preferred. That is, (a) the xylene-insoluble content at a temperature of 25 ° C. is 25 to 65% by weight, and (b) the xylene-soluble content at a temperature of 25 ° C. is (i) an average propylene content (F _P ) Is 20-80 mol%, and (ii) the propylene content (P _P ) of the copolymer (P _H ) formed at the active site where propylene is preferentially polymerized in the two-site model is 65-9.
0 mol% and (iii) the proportion of P _H in the copolymer (P
_f1 ) is 0.60 to 0.90. (A) The xylene-insoluble component is the ratio of the insoluble component that precipitates when the xylene-soluble component is measured. The component (C) of the present invention is preferably 25 to 65% by weight, and particularly preferably 30 to 65% by weight.
60% by weight is preferred. The (ii) xylene-soluble component is X1, and the properties determined by the two-site model are preferably in the above range. Specifically, components dissolved in ortho-xylene at a temperature of 25 ° C.
A temperature of 120 ° C. in a mixed solvent of 4-trichlorobenzene / deuterated benzene so that the polymer concentration becomes 10% by weight.
Heat to dissolve. This solution is placed in a ¹⁰ mmφ glass sample tube, and the ¹³ C-NMR spectrum is measured.

For example, a propylene-ethylene copolymer
FIG. 1 shows an example of a ¹³ C-NMR spectrum. In the spectrum, ten peaks shown in (1) to (10) appear due to differences in the chain distribution (the arrangement of ethylene and propylene). The name of this chain is Carman. CJ, et al; Macromolecules, Vol. 10, p.
536-544 (1977), and their names are shown in FIG.
Such a chain can be represented as a reaction probability (P) assuming a copolymerization reaction mechanism. When the total peak intensity is 1, the relative intensity of each of the peaks (1) to (10) is P Can be represented as a probability equation by Bernoulli statistics with That is, in the case of Sαα in (1), if the propylene unit is p and the ethylene unit is symbol e, the chains that can take this are [pppp] and [ppp].
e] and [eppe], each of which is represented by a reaction probability (P) and added together. The remaining (2) ~ (1
An equation is also established for the peak of (0) in the same manner, and these 1
It can be obtained by optimizing P so that the zero expression and the actually measured peak intensity become closest.

The two-site model referred to in the present invention is a model that assumes this reaction mechanism, and is described in HNCHENG;
plied Polymer Sience, Vol. 35, p. 1639-1650 (1988). That is, in the model of copolymerizing propylene and ethylene using a catalyst, polymerized preferentially ethylene and propylene content (P _P) of the copolymer generated at the active sites of polymerization preferentially propylene (P _H) Assuming two values of the propylene content (P ' _P ) of the copolymer formed at the active site and using the ratio of P _H to the copolymer (P _f1 ) as a parameter, the probability equation shown in Table 1 is obtained. . P _P , P ′ _P and P are set so that the relative intensities of the ¹³ C-NMR spectrum described above agree with the probability equations shown in Table 1.
It is obtained by optimizing three parameters of _f1 . (C) of the xylene solubles in component (i) an average propylene content of the present invention (F _P) is obtained by the following equation using the above three parameters. _{F P = P P × P f1} + P P '× (1-P f1) F P sought (mol%) The above formula is 20 to 80 mol%, more preferably from 30 to 70 mol%. Further, the (ii) P _P of the parameters is preferably 60 to 90 mol%, especially 65 to 85 mol% are preferred. Further, (iii) P _f1 is preferably 0.60 to 0.90, and particularly preferably 0.68 to 0.82.

The method for obtaining the component (C) of the present invention includes:
A slurry polymerization method performed in the presence of an inert hydrocarbon such as hexane, heptane, kerosene or a liquefied α-olefin solvent such as propylene, a gas phase polymerization method without a solvent, and the like are exemplified. The temperature condition is from room temperature to 130 ° C., preferably 5 ° C.
The reaction is performed under the conditions of 0 to 90 ° C. and a pressure of ^{2 to} 50 kg / cm ² . As the reactor in the polymerization step, those usually used in the technical field can be appropriately used.For example, a stirred tank reactor, a fluidized bed reactor, a continuous reactor using a circulation reactor, a batchwise reactor, and a batch reactor can be used. Either method may be used. Specifically, it is obtained by using a known multi-stage polymerization method. That is, a method in which propylene and / or a propylene-α-olefin copolymer is polymerized in a first-stage reactor, and then propylene and an α-olefin are copolymerized in a second-stage reaction. For example, the union is described in JP-A-4-224809,
JP-A-3-97747, JP-A-4-96912, JP-A-4-96907, JP-A-3-174
No. 410, JP-A-2-170803, JP-A-2-170802, JP-A-3-205439, JP-A-4-153203, JP-A-5-930
No. 24, JP-A-4-261423 and the like. Examples of commercially available products include, for example, “Product name: Cataloy” and “Tokuyama product name:
P. E. FIG. R "and Chisso Corporation" trade name: Newcon "Idemitsu Petrochemical" trade name: TPO "are preferred.

According to the two-site model, the component (A) has a xylene-soluble component at a temperature of 25 ° C.
(I) Average propylene content (F
_P ) is preferably 30 to 70 mol%, and more preferably 35 to 68 mol%.
Mol%, particularly preferably 38 to 65 mol%. (I
i) The propylene content (P _P ) of the copolymer (P _H ) formed at the active site where propylene is preferentially polymerized in the two-site model is 60 to 90 mol%, preferably 63
-85 mol%, particularly preferably 65-83 mol%. The ratio of (iii) P _H occupies the copolymer (P _f1) is a 0.30 to 0.70, preferably 0.35-0.65, particularly preferably 0.38 to 0.6
0.

The multilayer laminate of the present invention is a laminate comprising at least three layers in which the component (A) serves as both outer layers and the component (B) serves as an intermediate layer. The thickness ratio of the (A) layer and the (B) layer is (A) layer / (B) layer / (A) layer = 0.5 to 2.0.
/6.0-9.0/0.5-2.0, preferably 0.6-1.7 / 6.6-8.8 /
0.6-1.7, particularly preferably 0.8-1.
It is in the range of 5 / 7.0 to 8.4 / 0.8 to 1.5.
When the thickness ratio of the (A) layer is less than 0.5, the occurrence of blemishes and heat resistance are poor. On the other hand, if it exceeds 2.0, whitening resistance,
The impact strength and the decrease in heat seal strength after retort sterilization are large, which is not preferable. Regarding the total thickness of the multilayer laminate of the present invention, for example, in the case of a film, it is usually 20 to 1
80 μm. When the thickness is less than 20 μm, the heat seal strength is poor. Is not preferred. On the other hand, when it exceeds 180 μm, heat sealability and transparency are inferior. Preferably from 30 to 170 μm, particularly preferably 4
0 to 160 μm.

The heat sterilization in the present invention is a method for killing microorganisms, which are the main cause of food deterioration, and is usually carried out in a temperature range of 60 ° C. to 135 ° C., depending on the target bacteria. I have. Of these heat sterilizations, retort sterilization using heating steam at a temperature of 100 ° C. or higher and moist heat mainly containing hot water is performed at a high temperature for a short time so as not to impair the taste and flavor of the contents.

For each layer of the present invention, other additives commonly used in thermoplastic resins (eg, antioxidants, weathering stabilizers, antistatic agents, lubricants, antiblocking agents, antifogging agents, dyes) , Pigments, oils, waxes, fillers, etc.) and other thermoplastic resins can be added in an appropriate amount within a range not to impair the object of the present invention. For example, examples of such additives include 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol,
4'-thiobis- (6-t-butylphenol), 2,
2-methylene-bis (4-methyl-6-t-butylphenol), octadecyl 3- (3 ′, 5′-di-t-butyl-1′-hydroxyphenyl) propionate,
4,4′-thiobis- (6-butylphenol), and as an ultraviolet absorber, ethyl-2-cyano-3, 3-diphenylacrylate, 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxy -4
Octoxybenzophenone, dimethyl phthalate, diethyl phthalate as a plasticizer, wax, liquid paraffin, phosphate ester, pentaerythritol monostearate, sorbitan monopalmitate as an antistatic agent, sulfated oleic acid, polyethylene oxide, Carbon wax, ethylene bis stearoamide as a lubricant,
Butyl stearate, etc., carbon black, phthalocyanine, quinacridone, indoline, azo pigment, titanium oxide, red iron oxide, etc. as coloring agents, glass fiber, asbestos, mica, wollastonite, calcium silicate, aluminum silicate, carbonated Calcium and many other high molecular compounds can also be blended to such an extent that the effects of the present invention are not impaired.

The method of compounding the resin composition for the intermediate layer of the present invention is not particularly limited, and a known method can be used. For example, there is a method of mixing each component with a mixing machine such as a mixing roll, a Banbury mixer and a Henschel, tumbler, ribbon blender or the like, and then pelletizing using an extruder. Further, in the blending method, the components (A) and (C) may be dry-blended and directly supplied to a molding machine to form a film. The multilayer laminate of the present invention can be obtained by using a known extrusion laminate molding method and a molding machine for each of the above components. Also, using a known dry laminating molding machine and the like, further aluminum foil, metal deposition film,
Other materials such as a silicon oxide vapor-deposited film, a gas barrier layer such as a vinyldene chloride resin and a saponified ethylene-vinyl acetate copolymer, a polyester resin layer, a polyamide resin layer, and a polycarbonate resin layer can be laminated.

[0022]

The present invention will be described in more detail with reference to the following examples. The methods for measuring various physical properties used in the present invention are described below. (1) Xylene-insoluble and soluble components The polymer was once dissolved in ortho-xylene at a temperature of 130 so as to have a concentration of about 1% by weight, and then cooled to a temperature of 25 ° C. Those which were not used were regarded as ortho-xylene-soluble components, and their weight ratios were determined. Ortho-xylene solubles are the following ¹³ C-NM
Used for measurement of R spectrum. (2) ¹³ C-NMR spectrum measuring device: JNM-GSX400 manufactured by JEOL Ltd. Measurement mode: proton decoupling method Pulse width: 8.0 μs Pulse repetition time: 5.0 μs Number of integrations: 20,000 times Solvent: 1, Mixed solvent of 2,4-trichlorobenzene / deuterated benzene (75/25% by volume) Internal standard: hexamethyldisiloxane Sample concentration: 300 mg / 3.0 ml Solvent Measurement temperature: 120 ° C

(3) TCP1, TCP2 and area ratio (AR) by differential scanning calorimeter (DSC) Equipment: DSC7 type manufactured by PERKIN-ELMER Sample weight: about 3 to 5 mg Measurement method: 0 ° C. to 230 ° C. After the temperature was raised to 0 ° C and maintained for 5 minutes, the temperature was lowered to 0 ° C at a rate of 20 ° C / min to obtain a crystallization temperature curve. Tcp and peak area were determined from the obtained crystallization temperature curve. (4) Moldability After the start of the molding, blemishes occurred at the exit of the die, and it was evaluated by the following four steps based on the time required for the droplets to adhere to the film as droplets. ◎: 10 hours or more ・: 7 to 10 hours or less ・: 2 to 7 hours or less ・: 2 hours or less (5) Film impact strength Toyo Seiki according to ASTM D781 Using a film impact tester manufactured by Seisakusho, a temperature of 23 ° C. and −
The measurement was performed at 5 ° C.

(6) Heat Seal Strength The film was cut into a width of 15 mm, and the 180 ° peel strength was measured at a tensile speed of 300 mm / min using a tensile tester (RTA-100) manufactured by Orientec. (7) Whitening resistance Tube diameter 90 mm, stroke 178 mm, twist angle 44
0 degree, twist stroke 89mm, straight stroke 6
Using a Gelboflex tester manufactured by Tester Sangyo Co., Ltd. having a performance of 3.5 mm and a reciprocating speed of 40 times / min, the bending motion was performed 50 times, and evaluated by the following four grades. ◎ ・ ・ ・ ・ No whitened part is observed ○ ・ ・ ・ ・ Slightly whitened part is observed △ ・ ・ ・ ・ Whitened part is large and cannot be used × ・ ・ ・ ・ Significant whitening is observed and not usable

The materials used are shown below. (A) As an ingredient, an elastomer block content is 20% by weight,
85.6% by weight of xylene-insoluble matter, F of xylene-soluble matter
P 44.1 mol%, P _P is 74.9 mol%, P _f1 is 0.33, propylene -α- olefin block copolymer MFR of 2.3 g / 10 min (hereinafter "BPP1"
Was used. The MFR is 7.2 for comparison.
g / 10 minutes (hereinafter referred to as “PP1”).
And an ethylene-propylene random copolymer (hereinafter referred to as “PP2”) having an ethylene content of 4.6% by weight and an MFR of 6.8 g / 10 min. (C) As an ingredient, an elastomer block content is 65% by weight,
34.8% by weight of xylene-insoluble matter, F of xylene-soluble matter
P 66.5 mol%, P _P is 76.1 wt%, P _f1 is 0.77, propylene -α- olefin block copolymer MFR of 0.8 g / 10 min (Montell Co. CATALLOY KS353) (Hereinafter referred to as “BPP2”). For comparison, butene-1 content was 15% by weight, MF
R (190 ° C., load 2.16 Kg) is 1.4 g / 1
0-minute ethylene-butene copolymer (“Tuffmer A1085” manufactured by Mitsui Petrochemical Co., Ltd.) (hereinafter “EPR1”)
Ethylene-propylene copolymer having an ethylene content of 75% by weight and an MFR (temperature of 190 ° C., load 2.16 Kg) of 1.8 g / 10 min (trade name: Tuffmer P0480 manufactured by Mitsui Petrochemical Co., Ltd.) (Hereinafter referred to as "EPR2") and a linear low-density polyethylene having an MFR of 15.8 g / 10 minutes (hereinafter referred to as "PE1").

Examples 1 to 6 and Comparative Examples 1 to 7 [Adjustment of component (B)] After mixing with a tumbler in the combination and amount of each component shown in Table 2, a twin screw extruder manufactured by Kobe Steel Ltd. (KTX37 type), temperature 190-
Pelletized at 210 ° C. Each of the obtained pellets (A to
The DSC and xylene solubles of I) were measured. Table 2 shows the results. FIG. 3 shows a DSC crystallization curve of the pellet A. [T-die molding] Extruder having a diameter of 115 mmφ and a diameter of 65 mmφ, a die width of 3,400 mm, a lip gap of 0.8 with the above-mentioned pellets as intermediate layers in the layer configuration shown in Table 3.
Using a feed block type T-die molding machine manufactured by Toshiba Machine Co., Ltd., a film having a thickness of 70 μm was formed at a die temperature of 250 ° C. The thickness ratio between the surface layer and the intermediate layer was appropriately changed as shown in Table 3. [Heat Seal] Using a heat sealer manufactured by Tester Sangyo Co., a polyester film having a thickness of 12 μm and each of the above films were laminated by a dry lamination method, and heat sealed at temperatures of 160 ° C. and 170 ° C., a pressure of 2 kg / cm ² , and a time of 1 second. Processing was performed. [Retort treatment] The film heat-sealed as described above was treated at a temperature of 1 with RCS-4OT manufactured by Hisaka Seisakusho Co., Ltd.
A retort treatment was performed at 21 ° C. for 30 minutes. The heat seal strength and the whitening resistance after the retort treatment were measured. Table 4 shows the results.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

Industrial Applicability The multilayer laminate of the present invention has a small decrease in heat seal strength due to heat sterilization by retort sterilization or the like, is excellent in low-temperature impact strength, whitening resistance, and has little occurrence of blemishes and is excellent in productivity. It is suitably used as a food packaging material and a medical packaging material.

[Brief description of the drawings]

FIG. 1 is an example of a nuclear magnetic resonance spectrum of isotope carbon of an ethylene-propylene copolymer.

FIG. 2 is a view showing names of carbons derived from a chain distribution in a polyolefin.

FIG. 3 is an example of a DSC crystallization curve of the propylene-based polymer composition of the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E086 AD01 BA15 BB41 BB51 BB85 CA03 4F100 AK07C AK07J AK64A AK64B AK66A AK66B AK66C AK66J AL02A AL02B AL02C AL05C AL09A AL09B AL09C BA03 BA06 BA16 J10J23 J03 GB06 BP022 GF00

Claims (3)

[Claims] (A) (a) a polypropylene block
95-70% by weight, (b) propylene and 2-1 carbon number
2 (excluding 3) copolymer elastomer block with α-olefin Both outer layers comprising a propylene-α-olefin block copolymer comprising 5 to 30% by weight, and (B) (1) differential scanning type The crystallization temperature curve measured using a calorimeter has a main crystallization peak temperature (T _CP1 ) at a temperature of 105 to 110 ° C. and a secondary crystallization peak temperature (T _CP2 ) at a temperature of 65 to 85 ° C. And the ratio (AR) of the secondary crystallization peak area (T _CA2 ) to the main crystallization peak area (T _CA1 ) is at most 4.0% or less, and (2) xylene at a temperature of 25 ° C. Solubles (X
(3) The relation between the secondary crystallization peak temperature (T _CP2 ) and the xylene-soluble matter (XI) at a temperature of 25 ° C. is expressed by the following formula: T _CP2 ≦ −1.05 XI + 10
4. A multilayer laminate comprising at least three layers and an intermediate layer comprising a propylene-based polymer composition satisfying item 4. 2. An intermediate layer comprising: (A) a copolymer of (a) 95 to 70% by weight of a polypropylene block, and (b) a copolymer of propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3). Propylene-α-olefin block copolymer comprising 5 to 30% by weight of elastomer block 6
0 to 95% by weight and (C) (a) 60 to 30% by weight of a polypropylene block, and (b) propylene and carbon number 2
Soft propylene-α-olefin block copolymer composed of 40 to 70% by weight of a copolymer elastomer block with α-olefins of from 4 to 12 (excluding 3)
2. The multilayer laminate according to claim 1, comprising 0 to 5% by weight. 3. The multilayer laminate according to claim 2, wherein (C) the soft propylene-α-olefin block copolymer comprises a propylene-α-olefin block copolymer having the following physical properties (A) to (B). body. (A) Xylene insolubles at a temperature of 25 ° C. 25 to 65
Weight%, (ii) the xylene solubles at a temperature of 25 ° C.
(I) Average propylene content (F
_P) is 20 to 80 mole%, (ii) a copolymer of producing propylene at active sites polymerized preferentially in 2 site model (propylene content (P _P) is 60 to 90 mol% of P _H) and ( proportion iii) P _H occupies the copolymer (P _f1) is at 0.60 to 0.90