JPH0811270A - Laminate - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To prevent deterioration of transparency due to surface roughness when a block copolymer of a specific composition is formed into a film. [Structure] The following (b) layer is laminated on at least one surface of the following (a) layer, and the resin constituting the (a) layer is represented by the following formula: k = log (η ₂ / η ₁ ) (η ₁ , Η ₂ are melt shear viscosities [Pa · s] at shear rates of 10 ³ [s ⁻¹ ] and 10 ² [s ⁻¹ ] respectively, and the k value is 0.6 or more. , (B) layer has a k value smaller than 0.6. (A) A block copolymer containing a polybutene component, a polypropylene component, and a propylene-ethylene random copolymer component. (B) A resin layer made of polyolefin having a haze value of 5% or less at a thickness of 20 μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin laminate, and more particularly to a polyolefin laminate excellent in transparency and flexibility.

[0002]

2. Description of the Related Art Polyolefin elastomers have attracted attention and have been actively developed as polyolefin materials having flexibility and stretchability, but they are generally prone to melt fracture. Yes, it may limit the molding conditions and applications. For example, a block copolymer having a specific composition, that is, a block copolymer containing a polybutene component, a polypropylene component, and a propylene-ethylene random copolymer component, wherein the polybutene component is 0.01 to 5% by weight, and the polypropylene The component is 1 to 70% by weight, the propylene-ethylene random copolymer component is 25 to 98.99% by weight, and the propylene-ethylene random copolymer component is 10 to 80 mol% of ethylene-based monomer units. , 20 to 20 mol% of propylene-based monomer units
The containing block copolymer has excellent mechanical properties such as flexibility and impact resistance and transparency (Japanese Patent Laid-Open No. 5-9302).
4). However, the surface of the molded product tends to be rough during the molding process. Therefore, although the block copolymer having the above specific composition has a property of becoming transparent, there is a problem that the transparency is likely to be lowered depending on the molding processing conditions.

Therefore, when molding the block copolymer having the above specific composition, a molded article having a smooth surface and excellent transparency and flexibility is desired.

[0004]

As a result of intensive studies on the surface condition of a molded product, the present inventors have laminated a transparent polyolefin on the surface of a layer composed of a block copolymer having a specific composition. As a result, they have found that they can be molded articles that achieve the above objects, and have completed the present invention.

That is, according to the present invention, the following (b) layer is laminated on at least one surface of the following (a) layer,
The thickness of the layer (b) is 1 to 5 of the thickness of the layer (a) per layer.
The resin which is 0% and constitutes the layer (a) has the following formula: k = log (η ₂ / η ₁ ) (η ₁ and η ₂ are shear rates 10 ³ [s ⁻¹ ] and 10 ² [, respectively] s ^-1 ], the melt shear viscosity [Pa · s]) is 0.6 or more, and the resin constituting the layer (b) has a k value of less than 0.6. It is a laminated body characterized by.

(A) A block copolymer containing a polybutene component, a polypropylene component, and a propylene-ethylene random copolymer component, wherein the polybutene component is 0.
01 to 5% by weight, polypropylene component 1 to 70% by weight, propylene-ethylene random copolymer component 25
˜98.99% by weight, and the propylene-ethylene random copolymer component contains 1 unit of ethylene-based monomer units.
0-80 mol%, 90 monomer units based on propylene
A resin layer made of a block copolymer containing 20 to 20 mol%.

(B) A resin layer made of polyolefin having a haze value of 5% or less at a thickness of 20 μm.

The present invention will be described in detail below.

In the present invention, the block copolymer forming the layer (a) comprises a polybutene component, a polypropylene component and a propylene-ethylene copolymer component. If the polybutene component is replaced with another component, for example, a polyethylene component, the solidification property of the polymer particles of the block copolymer obtained by polymerization and the fluidity at high temperature are poor, and the production becomes difficult.

The polybutene component, the polypropylene component and the propylene-ethylene random copolymer component in the block copolymer used in the present invention have a proportion of 0.01 to 5% by weight of the polybutene component and 1 to 70% of the polypropylene component. %, And the propylene-ethylene random copolymer component is 25 to 98.99% by weight.

In the present invention, the polybutene component is essential for improving the particle properties of the copolymer particles of the block copolymer. In particular, when the content of the polypropylene component is small, for example, 30% by weight or less, the resulting polymer particles tend to stick, but even in such a case, due to the presence of the polybutene component, the polymer particles having good fluidity are obtained. Can be When the polybutene component is less than 0.01% by weight, when the polymer particles obtained by the polymerization are deposited and left to stand, they are solidified by the load, and when the polymer particles reach 50 to 70 ° C. It is not preferable because it has extremely poor fluidity. On the other hand, when the polybutene component exceeds 5% by weight, the fluidity of the polymer particles is rather lowered, which is not preferable. The ratio of the polybutene component is preferably in the range of 0.04 to 3% by weight in consideration of the better fluidity of the polymer particles.

If the polypropylene component is less than 1% by weight, the molding process becomes very difficult, while 70% by weight is required.
If it exceeds 5% by weight, the flexibility of the laminate is lost, which is not preferable. The polypropylene component is preferably in the range of 3 to 50% by weight in consideration of moldability and flexibility.

Further, the ethylene-propylene random copolymer component is 25 to 98.99% by weight. When the content of the above components is less than 25% by weight and when it exceeds 98.99% by weight, moldability becomes poor, which is not preferable. The ethylene-propylene random copolymer component is preferably in the range of 50 to 97% by weight in consideration of moldability.

The content ratio of each of the ethylene-based monomer unit and the propylene-based monomer unit in the propylene-ethylene random copolymer component is
The monomer unit based on ethylene is 10 to 80 mol%, preferably 15 to 60 mol%, more preferably 15 to 50 mol%. 90 to 20 monomer units based on propylene
Mol%, preferably 85 to 40 mol%, more preferably 85 to 50 mol%. When the content ratio of ethylene-based monomer units is less than 10 mol% and the content ratio of propylene-based monomer units exceeds 90 mol%, and when the content ratio of ethylene-based monomer units is 80 mol%. %, And the content ratio of the propylene-based monomer unit is less than 20 mol%, the moldability is deteriorated, which is not preferable.

The block copolymer used in the present invention includes:
Any one or more of polybutene component, polypropylene component, propylene-ethylene random copolymer component,
Other α-olefins may be copolymerized and contained in a small amount, for example, 5 mol% or less, as long as the physical properties of the block copolymer are not impaired.

The block copolymer used in the present invention is a so-called block copolymer molecular chain in which at least two kinds of polybutene component, polypropylene component and propylene-ethylene random copolymer component are arranged in one molecular chain. It is considered that the polybutene component, the polypropylene component, and the propylene-ethylene random copolymer component are mixed with the molecular chains of the individual so finely that they cannot be achieved by mechanical mixing.

The polybutene component in the block copolymer used in the present invention is used to prevent the particles of the block copolymer from solidifying,
In order to improve the fluidity at high temperature, the isotacticity is preferably 0.90 or more. Poly 1-
The isotacticity of butene was measured by ¹³ C-NMR, and the polymer journal (Polymer) was used.
J.) Volume 16 (1984) pp. 716-726.

The block copolymer used in the present invention can be obtained as a powder having excellent fluidity by polymerization. This is surprising considering that a conventional propylene-ethylene random copolymer having an ethylene content similar to that of the block copolymer used in the present invention is obtained in a lump form due to sticking of particles to each other.

The block copolymer particles used in the present invention are obtained by polymerization to have a high molecular weight and are degraded by an organic peroxide so that the melt index is adjusted to 0.1 to 10 g / min. It is preferable because it facilitates film forming.

The block copolymer used in the present invention can be obtained by a known method. A known method can be used for the degradation of the block copolymer obtained by polymerization with an organic peroxide.

Next, as the transparent polyolefin forming the layer (b) in the present invention, one having a haze value of 5% or less at a thickness of 20 μm is used. When the polyolefin forming the layer (b) alone is extruded into a film having a thickness of 20 μm, the haze value of the film must be 5% or less. Haze value of polyolefin is 5%
If it exceeds, the resulting laminate will not be transparent. Further, a polyolefin having a good compatibility with the block copolymer forming the layer (a) as a base material and having a relatively close thermal expansion coefficient and refractive index is particularly suitable as the layer (b).

The polyolefin forming the layer (b) preferably has a melt index of 0.1 to 30 g / 10 minutes, and more preferably 1 to 10 g / 10 minutes in order to improve the film moldability. It is preferable.

Specific examples of the polyolefin include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, homopolypropylene, random copolymer of propylene and ethylene, polybutene, ethylene-α-olefin copolymer, propylene. -Α-olefin copolymers, copolymers of ethylene-vinyl alcohol and its derivatives, copolymers of ethylene-α, β unsaturated carboxylic acids and their derivatives, and the like. Examples of the ethylene-vinyl alcohol derivative include an ethylene-vinyl acetate copolymer, and examples of the ethylene-α, β unsaturated carboxylic acid and its derivative include an ethylene-acrylic acid ester copolymer and ethylene-methacrylic acid. A copolymer is mentioned.

The thickness of the layer (b) to be laminated is (a)
It should be 1 to 50% of the layer thickness, preferably 5
~ 25%. When the thickness of the laminated polyolefin exceeds 50% of the thickness of the laminate, the laminate loses flexibility. On the other hand, when the thickness of the transparent polyolefin to be laminated is less than 1% of the thickness of the laminate, it is difficult to uniformly laminate the transparent polyolefin and the effect of laminating the polyolefin cannot be sufficiently obtained.

When the resin is melt-molded by an extruder or the like, the molten resin rapidly changes from a high shear state in the die to an extremely low shear state. Since the melt viscosity increases with a decrease in the shear rate, it is presumed that a rapid viscosity change occurs at the die outlet, which is one of the causes of melt fracture. By controlling the extrusion speed to a low value, the shear rate in the die can be decreased to suppress the above viscosity change, but it is not preferable in terms of productivity. In general, since the logarithm of the shear rate and the logarithm of the melt shear viscosity have a substantially linear relationship, the following equation k = log (η ₂ / η ₁ ) (η ₁ and η ₂ is the shear rate 10 ³ [s ⁻¹ ], respectively. And the melt shear viscosity [Pa · s] at 10 ² [s ⁻¹ ]), the smaller the k value, the less likely the melt fracture occurs.

The block copolymer constituting the layer (a) of the laminate of the present invention has the above k value of 0.6 or more. Therefore, when the resin forming the layer (a) was extruded, the surface was roughened due to the occurrence of melt fracture, and only a molded product having poor transparency was obtained.

The resin forming the layer (b) laminated on the layer (a) must have a k value of less than 0.6 in order to improve the poor transparency due to the surface roughness of the layer (a). .

The thickness of the above-mentioned layers (a) and (b) is not particularly limited, but is generally 1 to 100 μm, respectively.
It is preferably in the range of.

When the k value of the polyolefin as the layer (b) is 0.6 or more, the effect of laminating the layer (b) is not sufficient, and the effect of suppressing melt fracture cannot be expected.

In the present invention, an additive suitable for imparting a certain property to the laminate to be produced can be added to any layer as appropriate. For example, antioxidants, weathering agents such as ultraviolet absorbers, crystal nucleating agents, antiblocking agents, flame retardants, antifog agents, colorants, matting agents, antistatic agents, enzymes,
Examples include deodorants, fragrances, pesticides and the like. In addition to this, other components may be added if necessary, as long as the characteristics of the present invention are not impaired.

The method for producing the laminate of the present invention is not particularly limited, but the following method is preferably adopted. The resin for each layer granulated as required is extruded by a separate extruder at a temperature not lower than the melting point of the resin for each layer, laminated in a multilayer die, and extruded onto a laminate. It is not necessary to separately perform the step of forming the laminated body film by the kneading step and the film forming step, and a die may be attached to the tip of the kneading extruder to directly form the film. The laminate thus obtained may be unstretched or may be uniaxially or biaxially stretched after film formation. The stretching ratio is preferably in the range of 40 times or less in terms of area ratio.

[0032]

The laminate of the present invention is excellent in transparency and flexibility. Since the laminate of the present invention has the above excellent properties, it is most suitable for applications requiring transparency and flexibility. For example, various packaging films for food and medical use, protective films, trays, containers, shrink films, packaging films, agricultural films and the like can be mentioned.

[0033]

EXAMPLES Examples will be shown below to more specifically describe the present invention, but the present invention is not limited to these examples.

(A) Weight average molecular weight, ratio of molecular weight of 10,000 or less Measured by GPC (gel permeation chromatography) method. Water-based GPC-150C was used at a temperature of 135 ° C. using O-dichlorobenzene as a solvent. The column used was TSK gel GMH manufactured by Tosoh Corporation.
6-HT, gel size 10-15 μm. The calibration curve has a weight average molecular weight of 950, 2900 as a standard sample,
It was prepared by using 10,000, 50,000, 49.8 million, 2.7 million and 6.75 million polystyrene.

(B) Method for measuring respective proportions of ethylene-based monomer units and propylene-based monomer units in propylene-ethylene random copolymer component and method for measuring proportion of polybutene component ¹³ C-NMR spectrum It was calculated using a chart.
That is, the respective proportions of the ethylene-based monomer unit and the propylene-based monomer unit in the propylene-ethylene random copolymer component are determined by first determining the polymer (P
Polymer, Vol. 29 (1988), p. 1848, to determine the assignment of peaks, and then by the method described in Macromolecules, Vol. 10, (1977), p. 773. The respective proportions of ethylene-based monomer units and propylene-based monomer units were calculated.

Then, the weight and proportion of the polybutene component were calculated from the integrated intensity ratio of the peak derived from methyl carbon in the monomer unit and the peak derived from methyl carbon in the polybutene component based on propylene.

(C) Measurement of isotacticity of poly 1-butene Measurement was carried out by ¹³ C-NMR, and Polymer Journal (Polymer J.) Vol. 16 (1984) 71
Based on pages 6-726.

(D) Evaluation of caking property After the completion of the polymerization, about 100 g of polymer particles separated into monomers
Was placed in a 500 cc beaker having a diameter of 8 cm and a height of 15 cm and allowed to stand at room temperature for 1 week, and the state was observed. The criteria for evaluation were the following 5 ranks.

A: Almost no change from that before standing and no solidification.

B: The bottom is in a solidified state, but it is unraveled when an impact is applied C: The whole is solidified, but the whole is untied when an impact is applied D: The whole is solidified, The state where the whole is not loosened even when an impact is applied E: The state in which it is remarkably solidified and does not move in the form of a lump (e) Melt index The melt index was measured according to JIS K7210.

(F) Tensile elastic modulus It was measured by a tensile tester according to JIS-K-7127.

(G) Haze value and internal haze value The haze value was measured by a haze meter according to ASTM-D-1003-61.

The internal haze value was determined by applying paraffin to the surface to eliminate roughness, and to obtain ASTM-D-1003-6.
According to 1, measured with a haze meter.

The larger the difference between the haze value and the internal haze value, the more severe the surface roughness.

(H) Shear viscosity The melt viscosity is measured by Toyo Seiki Seisakusho Co., Ltd. CAPIROGRA.
It was measured by FIB using a capillary die having a diameter of 2 mm and a length of 20 mm. A sample of 18 dl was placed under a load of 40 kg in a cylinder heated to the measurement temperature for 3-4.
I preheated for a minute. After bleeding air, cross head speed 10, 30, 100, 300, 1000mm / mi
At n, the viscosity was measured, and from the logarithmic velocity-viscosity graph plotting 5 points, the shear rate was 10 ³ [s ⁻¹ ],
The viscosity of 10 ² [s ^-1 ] was determined.

The symbols in the table are as follows.

PP: Propylene ethylene random copolymer (Tokuyama Poly Tokuyama Polypro FB540) LL: Linear low density polyethylene (Mitsui Petrochemical Ultox UZ2520F) LD: Low density polyethylene (Mitsui Petrochemical Mirason F3
12) BLD: a mixture of a propylene ethylene random copolymer and low density polyethylene a: a block copolymer of Polymerization Example a aa: a reduced product of the block copolymer of Polymerization Example b bb: a block copolymer of Polymerization Example b Polymerization Example a (Preliminary Polymerization) A glass autoclave reactor having an internal volume of 1 liter equipped with a stirrer was sufficiently replaced with nitrogen gas, and then 400 ml of heptane was charged. Set the reactor temperature to 2
Keeping at 0 ° C., 0.18 mmol of diethylene glycol dimethyl ether, 22.7 mmol of ethyl iodide, 18.5 mmol of diethyl aluminum chloride, and titanium trichloride (“TOS-1” manufactured by Marubeni Solvay Chemical Co., Ltd.).
7 "), 22.7 mmol was added, and then propylene was continuously introduced into the reactor for 30 minutes such that the amount of propylene was 3 g per 1 g of titanium trichloride. The temperature during this period was kept at 20 ° C. After stopping the supply of propylene, the inside of the reactor was sufficiently replaced with nitrogen gas, and the obtained titanium-containing polypropylene was washed with purified heptane four times. As a result of the analysis, 2.9 g of propylene was polymerized per 1 g of titanium trichloride.

(Main Polymerization) Step 1: Polymerization of 1-Butene A stainless steel autoclave reactor having an internal volume of 1 liter equipped with a stirrer was sufficiently replaced with nitrogen gas, and then 400 ml of heptane was charged. Keeping the temperature inside the reactor at 20 ° C, diethyl aluminum chloride 18.15mmo
1, diethylene glycol dimethyl ether 0.18m
mol, ethyl iodide 22.7 mmol, 22.7 mmol of titanium-containing polypropylene obtained by prepolymerization as titanium trichloride, and then 1-butene was continuously added for 2 hours so that 1 g of titanium trichloride was 15 g. It was introduced into the reactor. The temperature during this period was kept at 20 ° C.
After the supply of 1-butene was stopped, the inside of the reactor was replaced with nitrogen gas to obtain a titanium-containing poly-1-butene polymer. As a result of the analysis, 14 g of 1-butene was polymerized per 1 g of titanium trichloride.

Step 2: Polymerization of Propylene and Copolymerization of Propylene-Ethylene 1 liter of liquid propylene and 0.70 mmol of diethylaluminum chloride were added to a 2 liter autoclave subjected to N substitution, and the internal temperature of the autoclave was adjusted to 7
The temperature was raised to 0 ° C. Add 0.087 mmol of titanium-containing poly-1-butene polymer as titanium trichloride, and add 6 at 70 ° C.
Polymerization of propylene was carried out for 0 minutes. During this time, hydrogen was not used. Then, the internal temperature of the autoclave was rapidly increased to 55 ° C.
At the same time as the temperature was lowered to 0.5, a mixed solution of 0.50 mmol of ethyl aluminum sesquiethoxide (EtAl (OEt)) and 0.014 mmol of methyl methacrylate was added, ethylene was supplied, and the ethylene gas concentration in the gas phase was 15 mo.
Copolymerization of propylene and ethylene was carried out at 55 ° C. for 120 minutes so that the concentration became 1%. During this period, the ethylene gas concentration was kept at 15 mol% while being confirmed by a gas chromatograph. During this time, hydrogen was not used. After the polymerization was completed, unreacted monomers were purged to obtain a particulate polymer. No adhesion was observed in the polymerization tank or on the stirring blade. The yield was 140 g, and the polymerization ratio of all polymers was 7370 g.
-Polymer / g-titanium trichloride.

30 kg of the resulting block copolymer
1,2-bis- (t-butylperoxyisopropyl) benzene was added in an amount of 0.02 PHR, and an antioxidant was further added in an amount of 0.1 PHR and mixed with a Henschel mixer. Melt kneading,
Pellets having a melt index of 1 g / 10 min were obtained.

Polymerization Example b In the main polymerization step 2 of Polymerization Example a, propylene was polymerized at a catalyst amount of 1.5 times at 55 ° C. for 30 minutes, and copolymerization of propylene and ethylene was conducted at a concentration of ethylene of 7 mol in the gas phase. %, 0.7 times the amount of organoaluminum, and 4 times the amount of methyl methacrylate were performed in the same manner as in Polymerization Example a.
In a separate polymerization experiment, the propylene polymerization ratio at this time was 13
It was 8 g-PP / g-TiCl. The results are shown in Table 1.

[0052]

[Table 1]

Example 1 The propylene-ethylene random copolymer (PP) shown in Table 2 was prepared from the extruder for the first and third layers by the block copolymer degradant (bb) obtained in Polymerization Example b. ) Is extruded from an extruder for the second layer into an annular multi-layer die at a discharge rate of the first layer: second layer: third layer = 1: 8: 1, and laminated at 190 ° C. in the annular multi-layer die to form a film. Extruded into. Next, air is blown into the molten cylindrical film, and the cooling water is brought into contact with the overflowed mandrel to solidify it by water cooling, and the draft 20, the blow-up 2, the take-up speed 30 m.
/ M to obtain a laminate having a thickness of 20 μm.

Example 2 In Example 1, the ratio of the extruder discharge amount of the first layer and the third layer and the extruder discharge amount of the second layer was calculated as follows: first layer: second layer: third layer = 1: The same procedure as in Example 1 was carried out except that the ratio was 4: 1.

Example 3 The same procedure as in Example 1 was carried out except that linear low density polyethylene was used as the constituent resin of the first and third layers.

Example 4 Example 4 was repeated except that low density polyethylene was used as the constituent resin of the first and third layers.

Example 5 Example 5 was carried out in the same manner as in Example 1 except that the resin constituting the second layer was the block copolymer degradant (aa) obtained in Polymerization Example a.

Example 6 In Example 1, the discharge amount of the third layer extruder was set to 0 kg.
The same procedure as in Example 1 was performed except that / h was set.

Comparative Example 1 The procedure of Example 1 was repeated, except that a single layer of the block copolymer reduced product (bb) obtained in Polymerization Example b was used.

Comparative Example 2 The procedure of Example 1 was repeated, except that a single layer of the block copolymer reduced product (aa) obtained in Polymerization Example a was used.

Comparative Example 3 In Example 1, the constituent resin of the first layer and the third layer was a 1: 1 mixture of propylene-ethylene random copolymer and low density polyethylene (haze value at 20 μm was 14.
The same procedure as in Example 1 was carried out except that (3%).

Comparative Example 4 The procedure of Example 1 was repeated except that the constituent resin of the second layer was the block copolymer of Polymerization Example a in which the resin was not degraded. The resin could not be extruded uniformly into a film.

[0063]

[Table 2]

[0064]

[Table 3]

Claims (1)

[Claims] 1. The following (b) layer is laminated on at least one surface of the following (a) layer, and the thickness of the (b) layer is 1 to 50% of the thickness of the (a) layer. , And (a)
The resin constituting the layer has the following formula: k = log (η ₂ / η ₁ ) (η ₁ and η ₂ are melt shear rates at shear rates of 10 ³ [s ⁻¹ ] and 10 ² [s ⁻¹ ] respectively. The laminate has a k value represented by a viscosity [Pa · s] of 0.6 or more, and the resin constituting the layer (b) has ak value of less than 0.6. (A) A block copolymer containing a polybutene component, a polypropylene component, and a propylene-ethylene random copolymer component, wherein the polybutene component is 0.01 to 5% by weight, the polypropylene component is 1 to 70% by weight, and propylene- The ethylene random copolymer component is 25 to 98.99% by weight, and the propylene-ethylene random copolymer component contains 10 to 80 mol% of ethylene-based monomer units and 90 to propylene-based monomer units. ~ 20 mol%
A resin layer comprising a block copolymer containing. (B) A resin layer made of polyolefin having a haze value of 5% or less at a thickness of 20 μm.