JPH08225692A - Polypropylene laminated sheet - Google Patents

Abstract

(57) [Summary] [Structure] Syndiotactic Polypropylene 30-9
5 parts by weight, and ethylene-octene copolymer 70 to 5
A polypropylene laminated sheet, comprising a polypropylene resin composition composed of parts by weight as a laminate layer and a polyolefin resin as a base layer. [Effect] The polypropylene laminated sheet of the present invention has an extremely low surface hardness as compared with the conventional polypropylene laminated sheet, and therefore has excellent flexibility and feel (touch feeling, soft feeling).
It is excellent in quality, can give a high-class feeling to the product, and is excellent in transparency and does not impair the appearance of the contents. Therefore, it is extremely useful especially as a packaging material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polypropylene laminated sheet having excellent transparency and flexibility.

[0002]

2. Description of the Related Art Generally, polypropylene is inexpensive and has excellent mechanical properties, hygiene compatibility, water vapor permeation resistance, and good appearance of molded products. Has been done. However, although polypropylene has excellent moldability, the surface of the molded product is inflexible and lacks a feeling of touch (feeling to the touch), so it does not have a high-class feel, and the transparency is low, so the appearance of the contents is inferior to the actual product. Therefore, the improvement was desired. Therefore, for example, as a method of increasing flexibility, a soft composition such as vulcanized rubber is attached to the outermost surface layer of the multilayer plastic container, or a vinyl acetate resin is laminated on the outermost layer of the multilayer container. Therefore, attempts have been made to improve flexibility and other properties as a container.

[0003]

However, although the product obtained by the former method has improved flexibility, it is difficult to say that it is sufficient in terms of transparency. Due to the contradictory tendency, there is a demand for shortening the manufacturing process, high feel and the like. Also, in the latter method, the vinyl acetate resin used is expensive, so not only does the product cost increase, but it is not allowed to be used in food or medical care due to odors. There was a problem that it could not be recycled. An object of the present invention is to provide a polypropylene laminated sheet having excellent molding processability, which is used for obtaining a packaging material having excellent transparency and flexibility, which solves the above problems.

[0004]

In view of the above-mentioned problems, the present inventors have earnestly studied a polypropylene laminated sheet excellent in transparency, flexibility, and moldability, and as a result,
By laminating a polypropylene resin composition comprising syndiotactic polypropylene and an ethylene-octene copolymer on at least one layer of the polypropylene laminated sheet, a polypropylene laminated sheet having excellent transparency and flexibility and good moldability can be obtained. Furthermore, since the syndiotactic polypropylene used in the present invention has a higher friction coefficient than the conventional isotactic polypropylene, the surface of the container becomes less slippery by laminating it on the surface of various containers. The present invention has been completed by finding that it is very effective in preventing the container from falling during carrying or loading, and that it has a supple and moist feeling and can impart desirable properties depending on the application.

That is, according to the present invention, in a multilayer extruded sheet having at least two layers having different compositions, a polypropylene comprising 30 to 95 parts by weight of syndiotactic polypropylene and 70 to 5 parts by weight of an ethylene-octene copolymer. The present invention relates to a polypropylene laminated sheet having a resin composition as at least one surface layer. In addition,
The inner layer and the outer layer (that is, the surface layer) in the present invention cannot be distinguished by the laminated sheet or the film itself, but can be distinguished by the use situation, and the outer layer that a person with good flexibility can see at the time of use (ie, The effect of the laminated sheet of the present invention is exhibited by making the surface layer). Hereinafter, the present invention will be described in detail.

The syndiotactic polypropylene used in the present invention may be syndiotactic homopolypropylene or syndiotactic polypropylene copolymer which is a copolymer of propylene and α-olefin. The syndiotactic pentad fraction determined by ¹³ C-NMR is 0.5 or more in the case of syndiotactic homopolypropylene,
0.7 or more is preferable and 0.75 or more is especially preferable.
In the case of syndiotactic polypropylene copolymer, the syndiotactic pentad fraction of the propylene chain is preferably 0.3 or more,
0.5 or more is preferable and 0.7 or more is particularly preferable.

The comonomer used in the syndiotactic polypropylene copolymer used in the present invention is used within a range that does not impair the transparency, flexibility and mechanical properties of the polypropylene laminated sheet of the present invention.
For example, olefins such as ethylene, 1-butene, 3-methyl-1-butene, 1-hexene, vinylcyclohexene, 1-decene, 1-hexadecene, cyclopentene, norbornene, hexadiene, octadiene, decadiene, dicyclopentadiene, 5 -Echilidene 2-
Examples thereof include copolymers containing dienes such as norbornene. Such a copolymer is preferably obtained by copolymerizing propylene and a comonomer in the presence of a known catalyst which gives a poly-α-olefin having good syndiotacticity. The content ratio of the comonomer differs depending on the comonomer and cannot be specified, but it is usually 1 to 30.
%, Preferably 5 to 15% by weight. The molecular weight of syndiotactic polypropylene is 0.1-10 d as the intrinsic viscosity measured in a tetralin solution at 135 ° C.
1 / g, preferably 0.5 to 5.0 dl / g.

The catalyst for producing syndiotactic polypropylene in the present invention is, for example, JP-A-2-4.
No. 1303, No. 2-41305, No. 2-274703, No. 2-274704, No. 3-179005, No. 3-17900.
Examples of the catalyst include a bridged transition metal compound having mutually asymmetric ligands and a cocatalyst as described in JP-A-6-69394 and JP-A-4-69394, but catalysts having different structures. However, any polypropylene can be used as long as it can produce polypropylene having a syndiotactic pentad fraction of 0.5 or more as measured by ¹³ C-NMR, and the polymerization method can be a slurry polymerization method, a bulk polymerization method, a gas polymerization method. Any of the phase polymerization methods can be used.

Since syndiotactic polypropylene has a slow crystallization rate, it is difficult to obtain a good molded product unless the extrusion speed is reduced to complete the melt solidification in order to uniformly laminate the composition. That is, the polypropylene resin composition containing syndiotactic polypropylene composed of 30 to 95 parts by weight of syndiotactic polypropylene and 70 to 5 parts by weight of ethylene-octene copolymer has good moldability. The resin composition used in the method of the present application comprises syndiotactic polypropylene and an ethylene-octene copolymer, and 40 to 80 parts by weight of syndiotactic polypropylene, preferably 5 parts by weight.
0-70 parts by weight, 60-ethylene-octene copolymer
By adjusting the amount to 20 parts by weight, preferably 50 to 30 parts by weight, moldability, transparency and flexibility are improved. 0.
When using a low syndiotactic pentad fraction of about 5 to 0.85, the moldability can be improved significantly by adding an ethylene-octene copolymer.

In the present invention, the octene content of the ethylene-octene copolymer, which is important for producing a polypropylene resin composition, is sufficient to obtain sufficient mechanical strength, flexibility and transparency as a molded article. 3-40% by weight is preferable, and 5-30% by weight is more preferable. The type of octene is not particularly limited, and any chain octene such as 1-octene, 2-octene, 3-octene, 4-octene, and other branched octenes can be used. Among them, 1-octene is preferable.

The molecular weight distribution index measured by gel permeation chromatography (hereinafter referred to as GPC), that is, the weight average molecular weight (hereinafter referred to as Mw) and the number average molecular weight (hereinafter referred to as Mn). The ratio of Mw / Mn is preferably 4 or less in order to obtain sufficient mechanical strength, flexibility and transparency as a molded product. As the molecular weight of the ethylene-octene copolymer, the melt flow index (190 ° C., 2.16 kg load, hereinafter referred to as MFI) is 0.05 to 70 g / 10 m.
In is preferable, and 0.5 to 30 g / 10 min is preferable. The density is 0.81 to 0.
96g / cm ³ is preferable, 0.85-0.93g /
cm ³ is preferable.

When the MFI of the ethylene-octene copolymer is less than 0.05 g / 10 min, the fluidity may be low, which may cause difficulty in compounding, and the MFI of 70 g / min.
If it exceeds 10 minutes, it may be difficult to obtain sufficient mechanical strength as a molded product obtained as a product, which is not preferable. Further, the density of the ethylene-octene copolymer is 0.
If it is less than 81 g / cm ^3, it may not be possible to obtain sufficient mechanical strength as a molded product obtained as a product, and if it exceeds 0.96 g / cm ³ , it is sufficient as a molded product obtained as a product. In some cases, flexibility may not be obtained, or in moldability may be reduced. In the present invention, as a catalyst for producing an ethylene-octene copolymer having the above-mentioned characteristics, a catalyst containing a metallocene compound as a main component as described in US Pat. No. 5,278,272 is used. Easily manufactured.

If necessary, the polypropylene resin composition of the present invention may contain other resins such as low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl alcohol copolymer, nylon, etc. and additives such as An antiblocking agent, a lubricant, a crystal nucleating agent, an ultraviolet absorber, a heat stabilizer, a weather resistance stabilizer, a radiation resistance agent, a pigment, a dye and the like may be added.

In the present invention, the resin used by being laminated with the polypropylene resin composition is a polymer mainly composed of ethylene, propylene, 1-butene, 1-pentene or a copolymer thereof, preferably polyethylene. , Polyolefin resins such as isotactic propylene homopolymer and crystalline isotactic ethylene-propylene random copolymer. In particular, as a packaging material, low-density polyethylene excellent in transparency, polyethylene such as medium-density polyethylene, isotactic propylene homopolymer, crystalline isotactic ethylene-propylene random copolymer, and further syndiotactic propylene homopolymer A composition prepared by blending a polymer and an isotactic propylene homopolymer or a crystalline isotactic ethylene-propylene random copolymer can be used.

When the polypropylene laminated sheet of the present invention is used as a packaging material or container for foods, pharmaceuticals, etc., the olefin has excellent barrier properties (permeation resistance) against various gases such as oxygen and aroma components. −
Vinyl alcohol copolymer, nylon, especially ethylene-
A vinyl alcohol copolymer can also be laminated. At that time, since the polypropylene resin composition and the polyolefin resin of the present invention have no adhesiveness with the ethylene-vinyl alcohol copolymer, a known adhesive layer during lamination,
For example, it is general to interpose polypropylene or the like which is graft-copolymerized with maleic anhydride.

The polypropylene laminated sheet of the present invention can be produced by a known method, for example, the following method. The polypropylene resin composition and the polyolefin resin of the present invention are extruded by an independent extruder so that the polypropylene resin composition is located in the outer layer (that is, the outer layer) and the polyolefin resin is located in the inner layer, and they are simultaneously extruded and laminated.

In the production of the polypropylene laminated sheet of the present invention, the die that can be used includes a die for a multilayer film and a die for a multilayer sheet. It is also possible to extrude with a separate die and stack them.
For example, a sheet of the polypropylene resin composition of the present invention, a polyolefin resin, and an ethylene-vinyl alcohol copolymer sheet may be produced in advance, and an adhesive may be used between them to press-bond and laminate them. These multi-layer laminates can be formed into tubes, sheets, films or the like by known methods depending on the application.

[0018]

EXAMPLES The following examples are provided for illustrating the present invention further in detail, but the present invention is not limited thereto. The measuring methods in the examples are as follows, and the measured values of hardness and haze are shown in Tables 2 and 3. In addition, Table 1 shows each composition of the resins used in Examples and Comparative Examples. (1) Melt index ASTM D-1238 (2) Surface hardness (JIS-A): JIS K6301 (3) Total haze: ASTM D-1003 (4) Internal haze: Liquid paraffin and toluene on both sides of the film or sheet. After applying the solution mixed at a ratio of 1: 1 (weight), the haze was measured according to the method of ASTM-D-1003. (5) Feel of the outer layer (that is, the surface layer) (feeling to the touch): The feeling of the surface layer portion of the multilayer sheet was evaluated by 10 persons (all of them are ordinary persons who are not specialized in the inspection). A: There is no sticky feeling, and there is a moist feeling and a supple feeling. ○: A supple feeling is felt, but there is no moist feeling. Δ: A supple feeling is felt, but there is no moist feeling and there is a voluminous feeling. X: There is no supple feeling, no moisturizing feeling, and there is a bulky feeling.

Example 1 Syndiotactic polypropylene homopolymer [SP
P-1: Melt flow index (hereinafter abbreviated as MFI) 3.2 g / 10 min, syndiotactic pentad fraction 0.787 measured by ¹³ C-NMR,
The intrinsic viscosity measured in a tetralin solution at 135 ° C. is 1.
39, the crystallization temperature measured by a differential scanning calorimeter is 7
4.6 ° C.] 50 parts by weight, and ethylene-octene copolymer (manufactured by Dow Co., Ltd., EG8100: MFI 1.0 g /
A polypropylene resin composition (composition B) consisting of 10 minutes, an octene content of 24% by weight, and a molecular weight distribution index Mw / Mn2.7 of 50 parts by weight, and an isotactic propylene-ethylene random copolymer (Mitsui) as a polyolefin resin. Toatsu Chemical Co., Ltd., EFL-100:
MFI 7.0 g / 10 min, ethylene content 4.9% by weight) was fed to each independent 30 mmφ extruder,
The crystalline isotactic propylene-ethylene random copolymer was first extruded by a two-layer T die at 200 ° C. so that the crystalline isotactic propylene-ethylene random copolymer was brought into contact with a cooling roll, and a laminated sheet was obtained at a roll temperature of 30 ° C. and a take-up speed of 5 m / min. The thickness of each layer of this laminated sheet was 280 μm for the composition B layer and 320 μm for the crystalline isotactic propylene-ethylene random copolymer layer. The results are shown in Table 2.

Example 2 Multilayer extrusion molding was performed in the same manner as in Example 1 except that the composition B layer was first extruded so as to come into contact with the chill roll in the method of Example 1. The thickness of each layer of this laminated sheet was 280 μm for the crystalline isotactic propylene-ethylene random copolymer layer and 320 μm for the composition B layer. The results are shown in Table 2.

Example 3 In the method of Example 1, as the polyolefin resin,
Syndiotactic polypropylene homopolymer (SP
P-1) 80 parts by weight and crystalline isotactic propylene-ethylene random copolymer (EFL-100)
A laminated sheet was obtained in the same manner as in Example 1 except that 20 parts by weight of the polyolefin resin composition (composition A) was used. The thickness of each layer of this laminated sheet was 28 for the composition B layer.
The composition A layer had a thickness of 0 μm and the composition A layer had a thickness of 320 μm. The results are shown in Table 2.

Example 4 In the method of Example 1, a polypropylene resin composition comprising 60 parts by weight of syndiotactic polypropylene homopolymer (SPP-1) and 40 parts by weight of ethylene-octene copolymer (EG8100) (composition A laminated sheet was obtained in the same manner as in Example 1 using C). The thickness of each layer of the laminated sheet was 280 μm for the composition C layer and 320 μm for the crystalline isotactic propylene-ethylene random copolymer layer. The results are shown in Table 2.

Example 5 A polypropylene resin composition (composition comprising 70 parts by weight of syndiotactic polypropylene homopolymer (SPP-1) and 30 parts by weight of ethylene-octene copolymer (EG8100) in the method of Example 1 Using D), a laminated sheet was obtained in the same manner as in Example 1. The thickness of each layer of this laminated sheet was 280 μm for the composition D layer and 320 μm for the crystalline isotactic propylene-ethylene random copolymer layer. The results are shown in Table 2.

Example 6 In the method of Example 1, 70 parts by weight of syndiotactic polypropylene homopolymer (SPP-1) and ethylene-octene copolymer (PL18, manufactured by Dow Co., Ltd.) are used.
40: MFI 1.0 g / 10 min, octene content 9.5% by weight, molecular weight distribution index Mw / Mn 2.1) 30
Polypropylene resin composition consisting of parts by weight (composition E)
Using, was obtained in the same manner as in Example 1 to obtain a laminated sheet. The thickness of each layer of this laminated sheet was 280 μm for the composition E layer.
m, and the crystalline isotactic propylene-ethylene random copolymer layer had a thickness of 320 μm. The results are shown in Table 2.
Shown in

Example 7 In the method of Example 1, as the polyolefin resin,
Isotactic propylene homopolymer (manufactured by Mitsui Toatsu Chemicals, Inc., JHH-G: MFI 8.0 g / 10 min)
Using, was obtained in the same manner as in Example 1 to obtain a laminated sheet. The thickness of each layer of this laminated sheet was 280 μm for the composition B layer.
m, the isotactic propylene homopolymer layer is 320
μm. The results are shown in Table 2.

Comparative Example 1 In place of EG8100, 50 parts by weight of syndiotactic propylene homopolymer (SPP-1) and ethylene-propylene copolymer (manufactured by Nippon Synthetic Rubber Co., Ltd., EP
-02P: MFI 3.2 g / 10 min, propylene content 26% by weight, molecular weight distribution index Mw / Mn 2.1) 5
A laminated sheet was obtained in the same manner as in Example 1 except that 0 part by weight of the polypropylene resin composition (composition F) was used. The thickness of each layer of this laminated sheet is 2 for the composition F layer.
The thickness was 80 μm, and the thickness of the crystalline isotactic propylene-ethylene random copolymer layer was 320 μm. Table 3 shows the results.

Comparative Example 2 Using the same resin composition and laminated body as in Comparative Example 1, a laminated sheet was obtained in the same manner as in Example 2. The thickness of each layer of this laminated sheet was 280 μm for the crystalline isotactic propylene-ethylene random copolymer layer and 320 μm for the composition F layer. Table 3 shows the results.

Comparative Example 3 A polypropylene resin composition (composition: 70 parts by weight of syndiotactic propylene homopolymer (SPP-1) and 30 parts by weight of ethylene-propylene copolymer (EP-02P) in place of EG8100. A laminated sheet was obtained in the same manner as in Example 5 except that the product G) was used. The thickness of each layer of this laminated sheet was 280 μm for the composition G layer and 320 μm for the crystalline isotactic propylene-ethylene random copolymer layer. Table 3 shows the results.

Comparative Example 4 Instead of SPP-1, crystalline isotactic propylene-ethylene random copolymer (EFL-100) 70
Parts by weight, and ethylene-octene copolymer (PL18
40) A laminated sheet was obtained in the same manner as in Example 6 except that 30 parts by weight of the polypropylene resin composition (composition H) was used. The thickness of each layer of this laminated sheet was 280 μm for the composition H layer and 320 μm for the crystalline isotactic propylene-ethylene random copolymer layer.
Table 3 shows the results.

Comparative Example 5 Instead of SPP-1 and EG8500, a crystalline isotactic propylene-ethylene random copolymer (EFL) was used.
Laminated sheet was obtained in the same manner as in Example 7, except that a polypropylene resin composition (composition H) consisting of 70 parts by weight of -100) and 30 parts by weight of ethylene-octene copolymer (PL1840) was used. It was Regarding the thickness of each layer of this laminated sheet, the composition H layer was 280 μm, and the isotactic propylene homopolymer (JHH-G) layer was 320 μm. Table 3 shows the results.

Comparative Example 6 Only the crystalline isotactic propylene-ethylene random copolymer, EFL-1100, was extruded at a temperature of 200.
A single-layer sheet was formed at a temperature of 5 ° C. and a take-up speed of 5 m / min to obtain a sheet having a thickness of 600 μm. Table 3 shows the results.

Comparative Example 7 Only the isotactic propylene homopolymer, JHH-G, was extruded at a temperature of 200 ° C. and a take-up speed of 5 m / min to form a single-layer sheet to obtain a sheet having a thickness of 600 μm. Table 3 shows the results.

All the sheets of Comparative Examples 1 to 7 had a total haze of 24% or more and an internal haze of 20% or more, and were clouded whitish in terms of transparency (transparency).
There was no clear and transparent feeling as compared with the composition obtained in 1.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

The polypropylene laminated sheet of the present invention is
The surface hardness is much lower than that of conventional polypropylene laminated sheets, so it has excellent flexibility, good feel (feeling to touch, soft feeling), can give a high-class feel to the product, and is excellent in transparency and impairs the appearance of the contents. Therefore, it is extremely useful as a packaging material.

Claims (1)

[Claims] 1. A multi-layered extruded sheet comprising at least two layers having different compositions, comprising a polypropylene resin composition comprising 30 to 95 parts by weight of syndiotactic polypropylene and 70 to 5 parts by weight of an ethylene-octene copolymer. A polypropylene laminated sheet having at least one surface layer.