JP2003191930A - Multilayered container excellent in resistance to dropping shock - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered and light container highly resistant to dropping shock and made of scrap materials reclaimed from a manufacturing process and with no records of scorching in heat hysteresis during manufacture. <P>SOLUTION: The multilayered container composed of layers of at least (A) a layer that contains base material resin (a), (B) a barrier resin layer (b) and (C) a layer that contains adhesive resin (c) composed of graft-modified resin of ethylene-α olefin copolymer polymerized by metallocene catalyst, and also a layer with reusable resin layers consisting of at least one layer that contains (a), (b) and (c). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

The present invention relates to a layer containing at least a base resin, an oxygen barrier resin layer, and a layer containing an adhesive resin made of an acid-modified resin of an ethylene-α-olefin copolymer polymerized by a metallocene catalyst. The present invention relates to a multilayer container.

[0002]

2. Description of the Related Art Containers made of synthetic resin are widely used. For example, an oxygen barrier resin layer is arranged in a multi-layered container in order to prevent deterioration of contents due to permeation of oxygen. In these multilayer containers, an adhesive resin layer is arranged between the base resin and the oxygen barrier resin layer to bond the layers. Conventionally, a graft-modified adhesive resin with a low-density polyethylene or high-density polyethylene-based unsaturated carboxylic acid or its derivative has been used as an adhesive resin for a multi-layer container. These adhesive resins have some excellent adhesiveness to the barrier resin having a polar group, but have the following problems.

[0003]

In recent years, in the field of multi-layer containers, which produce a large amount of products, due to the sharp rise in the prices of synthetic resins and environmental problems caused by wastes, in addition to the desire to reduce the weight of the containers as much as possible, There has been a strong demand to collect scraps produced by container production and reuse them efficiently. In particular, in the rotary blow molding method for bottles, burrs are unavoidable because there is a gap between the molds, and a constant amount of burrs always occurs in steady production. Further, cutting scraps are generated in the bottle finishing process (reamer or the like), and it is required to efficiently regenerate these as bottles. In addition, the amount of adjustment bottles required to determine the molding conditions cannot be ignored. In the bottle industry these days,
Scrap (in the following, recovered resin or reground:
(Also referred to as REG, etc.) as much as possible, and the amount of resin to be discarded is reduced to the limit to achieve efficient production. In the case of reducing the weight of a conventional multi-layered container using an adhesive resin, the weight of the container is limited at the time of molding or because the adhesiveness of the molded product container is insufficient. In addition, low density polyethylene (hereinafter abbreviated as LDPE) and high density polyethylene (hereinafter HD
Abbreviated as PE), a recovered resin that recovers scraps such as burrs generated in the production of a multilayer container using an adhesive resin of
Since these adhesive resins are included, the hardness and brittleness of the adhesive resin affect the physical properties of the scrap material, and problems such as drop strength drop and delamination during handling occur. Linear low density polyethylene polymerized by Ziegler-Natta catalyst (L
The LDPE) -based adhesive resin itself has a high material strength, but due to the presence of a low molecular weight, the interface with the dispersed particles of the barrier resin having a polar group becomes weak, and the drop strength decreases.
This tendency is particularly remarkable when the weight of the multilayer container is reduced. This is because if the weight of the container is reduced while maintaining the barrier function of the container, the ratio of the thickness of the relatively hard and brittle barrier layer increases, and the ratio of the barrier resin in the recovered resin layer increases. Further, in the recovered resin layer, as the molten resin flows through the interface with a metal such as an extruder or a die, barrier resin particles dispersed in the vicinity of the interface are deposited and become a skin-like kogation due to heat history. The kogation impairs the hermeticity of the container and causes a poor appearance. Thus, in the conventional technology,
It was very difficult to collect and reuse scrap materials. The present invention provides a lightweight multi-layer container having a special layer structure, in which scrap materials generated during the production of the multi-layer container can be recovered and reused in the production of the multi-layer container.

[0004]

Means for Solving the Problems The present invention provides "1. at least A. a layer containing a base resin (a);
B. A barrier resin (b) layer, and C.I. A multilayer container comprising a layer containing an adhesive resin (c) made of a graft acid-modified resin of an ethylene-α-olefin copolymer polymerized by a metallocene catalyst. 2. The multi-layer container according to item 1, wherein at least one layer has a recovered resin layer containing (a), (b), and (c). 3. Item 1. The base resin (a) is one or more resins selected from propylene-based resins, low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymers, and ethylene-α-olefin copolymers. Described in,
Multi-layer container. 4. The barrier resin layer (b) is a layer containing one or more resins selected from an ethylene-vinyl alcohol copolymer, a polyamide resin, a polyester resin, and a cyclic polyolefin resin. The multi-layered container described in the section. 5. Adhesive resin (c) has a density of 0.93 g / cm ³ or less, MF
R is 0.5 to 10.0 g / min, the degree of graft modification with an unsaturated carboxylic acid or its derivative is 0.3 to 5% by weight, 1 to
The multi-layer container described in any one of 4 above. 6. Item 6. The recovered resin layer is a layer in which the contents of the adhesive resin (c) and the barrier resin (b) are adjusted to a weight ratio of 1: 1 to 1:10. Multi-layer container. 7. The layer containing the adhesive resin (c) was selected from a layer made of a mixture of the adhesive resin (c) and the base resin (a), a layer made of a recovered resin, and a layer made of a mixture of the recovered resin and the adhesive resin (c). The multilayer container according to any one of items 1 to 6, which is any one. 8. The multi-layer container according to any one of items 1 to 7, wherein the base resin (a) layer comprises a layer made of an ethylene resin and a layer made of a propylene resin. Regarding

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Conventional graft-modified (hereinafter simply referred to as graft, graft-modified, modified, etc.) LDPE, HDPE-based unsaturated carboxylic acid or its derivative is used as an adhesive such as ethylene-vinyl alcohol copolymer. It is possible to select one having good adhesiveness to a barrier resin having a polar group, but the hardness and brittleness of the material itself directly affect the physical properties of the recovered material or the recovered resin layer. LDPE
The presence of long chain branching not only affects the adhesiveness of HDPE due to its high crystallinity, but also causes the physical properties of the recovered resin layer to deteriorate when the recovered resin is used again in the bottle, which reduces the drop strength of the bottle. However, cracks may occur in the recovered resin layer during handling, and problems such as so-called delamination may occur. In addition, LLD with normal Ziegler-Natta catalyst
The PE-grafted adhesive resin itself has high material strength, but the presence of the low-molecular weight component tends to weaken the interface of dispersed particles of the ethylene-vinyl alcohol copolymer as a recovery material. In particular, a drop in drop strength is a major obstacle in reducing the weight of a bottle. In the conventional adhesive resin, not only the particulate dispersion of the ethylene-vinyl alcohol copolymer in the recovered resin layer becomes non-uniform, but the molten resin flows through the interface with the metal in the extruder, piping system, die, etc. As a result, particles tend to precipitate near the interface, which eventually becomes a skin-like kogation due to a long-term thermal history. On the other hand, by using an adhesive resin (hereinafter referred to as a metallocene adhesive) composed of a graft modified resin of an ethylene-α-olefin copolymer polymerized by the metallocene catalyst of the present invention, ethylene-
As a result of stabilizing the particulate dispersion of the vinyl alcohol copolymer, precipitation of particles is suppressed, and as a result, kogation is prevented. It is also effective to add an additional adhesive resin to the recovered resin layer in an amount of 3 to 10% by weight as long as the physical properties of the recovered resin layer are not impaired.

The adhesive resin itself based on a metallocene-catalyzed ethylene-α-olefin copolymer is, for example,
As described in JP 2001-98121 A, a predetermined amount of an unsaturated carboxylic acid such as maleic anhydride or itaconic acid or a derivative thereof is added to a base ethylene-α-olefin copolymer in a solution or It can be obtained by graft modification by a known method such as melt extrusion in an extruder. It is known to form a multilayer film or sheet by using this modified copolymer as an adhesive. α ・
Olefin comonomers include, but are not limited to, butene-1, hexene-1, 4-methylpentene-
Known compounds such as 1, 1, octene-1 and the like are used. However, as shown in the following examples, when a copolymer having a carbon number of 6 or more is used as the comonomer, adhesion of the ethylene resin and the propylene resin is achieved. It is also effective for propylene-based bottles. When the metallocene adhesive is used, a good effect can be obtained in adhering the polyethylene resin and the polypropylene resin. In particular, a low density resin composed of an α-olefin having a large carbon number is preferably used for such an application.

The recovered resin referred to in the present invention means at least A. A layer containing the base resin (a) and B. The barrier resin layer (b) and C.I. (A) of a layer containing a metallocene adhesive (c)
A resin mixture containing a resin composed of three components of + (b) + (c), such as burrs and adjustment bottles mainly generated in the production of a multilayer container in which layers A to C are laminated. This is a resin from which scrap is collected. Regarding the molecular weight distribution of the metallocene adhesive, Mw / Mn of 1.8 to 4.6 is preferable because it is effective in stabilizing the dispersion of the barrier resin in the recovered resin layer. In the layer made of the recovered resin used in the present invention, the recovered resin may be used alone, or the recovered resin may be further mixed with a base resin. When the recovered resin layer is a layer consisting of the recovered resin alone, when the content of the metallocene adhesive contained in the recovered resin is 1: 1 to 1:10 with respect to the oxygen barrier resin, the metallocene adhesive is used as a single layer. Even if it is not used, the adhesiveness with the barrier resin layer becomes good, and a multilayer container can be practically used.

When the recovered resin layer is a layer made of a resin in which the recovered resin and the base resin are mixed, the adhesive layer is not always necessary if the metallocene adhesive contained in the layer is 3% by weight. If it is less than this, it is necessary to dispose the metallocene adhesive layer. Of course, a metallocene adhesive layer may be placed. In the multilayer container of the present invention, the metallocene adhesive layer is arranged between the layers of the multilayer, but it is always arranged between the base resin layer and the barrier resin layer. If the metallocene adhesive of the recovered resin layer is adjusted to 0.5% by weight or more based on the total amount of the base resin and the barrier resin, the metallocene adhesive is not disposed between the recovered resin layer and the barrier resin layer. Although it may be provided, the metallocene adhesive layer may be provided even within the range although it is necessary to provide the film outside the range. The same applies between the base resin layer and the recovered resin layer.

Low density polyethylene (LD
Abbreviated as PE), high density polyethylene (abbreviated as HDPE), ethylene-vinyl acetate copolymer resin (abbreviated as EVA), ethylene-α / olefin copolymer, random polypropylene containing ethylene, butene 1, etc.,
It is formed of one or more selected from block polypropylene. A well-known resin used in a conventional blow molding container is used as a main resin of the base resin, and a density of 0.900 to 0.975 g / cm ³ , as a polyethylene resin,
MFR in the range of 0.3 to 3.0 g / min is used, and polypropylene resin has a density of 0.875 to 0.915 g / cm ³ , MFR0.6.
Those in the range of ~ 4.5 g / min are used. The layer made of a barrier resin is formed of one or more selected from an ethylene-vinyl alcohol copolymer (abbreviated as EVOH), a polyamide resin, a polyester resin, and a cyclic polyolefin (abbreviated as COC).

The layer containing the metallocene adhesive may contain an amount of the metallocene adhesive that acts as an adhesive,
There are a layer made of a metallocene adhesive, a layer made of a mixture of a metallocene adhesive and a base resin, a layer made of a recovered resin, and a layer made of a mixture of a recovered resin and a metallocene adhesive. The recovered resin may be crushed and used as it is, or may be used in the form of pellets. The multilayer container of the present invention is manufactured by a known molding method using a plurality of extruders according to the resin of each layer and a multilayer die. As a method of handling the multi-layer parison, known methods such as a rotary plow molding method and a shuttle method of drawing down are used.

The MFR of the metallocene adhesive of the present invention is higher than that of the base resin or the recovered resin and is preferably at most twice that of the barrier resin from the viewpoint of appropriately suppressing the size of dispersed particles. For example, ethylene-vinyl alcohol copolymer: When MFR is 1.0 to 2.0, 2.
It is preferably in the range of 0 to 4.0 g / min. MF
If R largely deviates from this relationship, it will be difficult to achieve particulate dispersion, and delamination, cracking, etc. will occur due to poor dispersion. In addition, light transmission becomes nonuniform, and defects such as poor dispersion occur particularly at singular points such as welds. Even in multi-layer extrusion, an extreme MFR deviation causes a resin pressure abnormality or the like, resulting in a variation in layer thickness and, in an extreme case, resin breakage, which is a fatal defect. For the purpose of further improving the dispersion of the barrier resin such as ethylene-vinyl alcohol copolymer in the metallocene adhesive, it is also effective to add a known neutralizing agent such as hydrotalcite, a phenolic compound, a known antioxidant such as phosphorus, etc. Target. The recovered resin is used not only as a layer formed using only this, but also as a base resin and the like in combination.

Next, a laminated structure forming the multilayer container of the present invention will be illustrated. Example of layer structure: from outer layer side, three-layer structure: LLDPE + REG / LLDPE + REG,
LLDPE + AD / EVOH / LLDPE + REG, P
ET / AD / HDPE + REG Four-layer structure: LLDPE + REG / EVOH / LLDPE
+ REG / LDPE or EVA, LLDPE / COC / AD / HDPE + REG PET / AD / HDPE + REG / HDPE LLDPE / LLDPE + REG / EVOH / LLDP
E + REG, five-layer structure: LLDPE / LLDPE + REG / EVOH
/ LLDPE + REG / LLDPE, LLDPE / LL
DPE + REG / COC / LLDPE + REG / LLD
PE, LLDPE + REG / AD / EVOH / AD / L
LDPE, 6-layer structure: LLDPE / AD / EVOH / AD / LLD
PE + REG / LLDPEorLDPEorEVA, L
DPEorEVA / AD / EVOH / AD / LLDPE
+ REG / LDPE LLDPE / AD / EVOH / AD / LLDPE + RE
G / LLDPE, HDPE / COC / AD / EVOH /
AD / HDPE + REG, LLDPE / LLDPE + R
EG / AD / EVOH / AD / LLDPE or LDPE
orEVA, LLDPE / AD / EVOH / AD / RE
G / LLDPE PP / AD / EVOH / AD / PP + REG / PP, L
LDPE / AD / EVOH / AD / COC / LLDP
E, 7-layer structure: LLDPE / LLDPE + REG / AD / E
VOH / AD / LLDPE + REG / LLDPE HDPE / HDPE + REG / AD / EVOH / AD /
HDPE + REG / HDPE, LDPE or EVA / L
LDPE + REG / AD / EVOH / AD / LLDPE
+ REG / LDPE or EVA LLDPE / COC / AD / EVOH / AD / LLDP
E + REG / LLDPE, 8-layer structure: LLDPE / LLDPE + REG / COC /
AD / EVOH / AD / LLDPE + REG / LLDP
E, REG in the diagram is a recovered resin, AD is a metallocene adhesive, PET is polyethylene terephthalate, and PP is polypropylene. Those that are tied together, such as LLDPE + REG, are mixtures. LDPE, LLDP
E, HDPE and EVA are base resins.

Next, an example of the basic structure of the multilayer container of the present invention will be described with reference to the drawings. 1 to 4 show the basic structure when the metallocene adhesive is applied to a multilayer container, and FIGS. 5 to 7 show various multilayer containers. The upper layer is the outer layer. Figure 1
Shows the layer structure of a 4-layer, 7-layer multilayer container. Reference numerals 1 and 5 are layers containing a base resin and are formed of a polyolefin resin. Reference numeral 2 denotes a layer containing a recovered resin, which is formed of a mixture of the recovered resin and a polyolefin resin as a base resin. 3 is a metallocene adhesive layer. 4 is a barrier resin EVOH
Is formed by. 5 is an inner layer. FIG. 2 shows the layer structure of a multilayer container of 6 layers of 4 types. Reference numeral 1 denotes a layer made of a base resin, which is made of a polyolefin resin. Reference numeral 2 denotes a layer containing a recovered resin, which is formed of a mixture of a polyolefin resin as a base resin and a recovered resin. 3 is a metallocene adhesive layer. A barrier resin layer 4 is formed of EVOH. 3 and 4 show the layer structure of a multi-layer container of four layers and five layers. In these examples, the layer structure of the example in which the adhesive layer between the barrier layer and the metallocene adhesive is used or the recovery resin containing the metallocene is used is omitted. Reference numeral 1 denotes an outer layer made of a base resin, which is made of a polyolefin resin. Reference numeral 2 denotes a layer containing a recovered resin, which is formed of a mixture of a polyolefin resin, a recovered resin and a metallocene adhesive in FIG. 3, and is formed of a mixture of a polyolefin resin and a recovered resin in FIG. 3 is a metallocene adhesive layer. 4 is a barrier resin layer. FIG. 5 shows the layer structure of a multilayer container of 6 layers of 5 types. Reference numerals 1 and 5 are layers containing a base resin, which are layers formed of LDPE. Reference numeral 2 is a layer made of recovered resin, which is formed of a mixture of polypropylene resin and recovered resin. 3 is a layer made of a metallocene adhesive. 4 is a barrier resin layer. FIG. 6 shows the layer structure of another multi-layer container of 5 types and 6 layers. Reference numerals 1 and 5 are layers containing a base resin, and are formed of LLPE, LLDPE or PP. Reference numeral 6 denotes a layer containing the recovered resin, which is formed only of the recovered resin. 3 is a metallocene adhesive layer. A barrier resin layer 4 is formed of EVOH. The inner layer 5 is made of PP. FIG. 7 shows a layer structure of a four-kind four-layer container. 5 is a layer containing a base resin, and 7 is PE
It is made of T. Reference numeral 2 denotes a layer containing the recovered resin, which is formed of a mixture of PP or HDPE and the recovered resin. 7
And the metallocene adhesive layer 3 is disposed between the two. 5
Is an inner layer and is made of PP or HDPE.

[0014]

EXAMPLES Example 1, Comparative Examples 1 to 3 Here, the characteristics of a multi-layer container were compared in the case of using a metallocene adhesive and a conventional adhesive, respectively. As the adhesive, various adhesives having the characteristic values shown in Table 1 were used, and HDPE: density 0.952 g / c was used as the base resin.
m ³ , MFR 0.7 g / 10min, containing ethylene as a barrier material
32 mol EVOH was used. Each of the adhesives was subjected to a predetermined maleic anhydride graft modification to obtain a graft rate modification with approximately 0.5% by weight of an unsaturated carboxylic acid or a derivative thereof.

[0015]

[Table 1]

(Note) Metallocene LL represents an ethylene-α-olefin copolymer polymerized by using a metallocene catalyst as a base resin. From outer layer, HDPE / AD /
EVOH / AD / HDPE + REG / HDPE (layer ratio:
20/3/4/4/60/10% by weight)
A seed 6-layer bottle, a bottle with a handle of 64 g and a content of 1700 ml with a handle for cooking oil was subjected to rotary blow molding. The recovered resin layer contained 40% by weight of burr, reamer layer and crushed bottle. As a metallocene adhesive, a copolymer of ethylene and hexene-1 with a wide molecular weight distribution M
A bimodal distribution base resin with w / Mn = 4.5 was used. Thereby, molding conditions such as resin pressure at the time of molding can be set almost the same as those of the other adhesives (Comparative Examples 1 and 2), and even in a complicated shape such as a handle, a uniform layer can be formed in each part. I was able to secure the configuration. In the adhesive material of Comparative Example 3, even if the set resin temperature was lowered to the limit, the resin pressure of the adhesive material layer was remarkably reduced as compared with the other cases, and it was difficult to secure the uniformity of the EVOH film thickness. The following items were evaluated for the obtained bottles. Tensile impact strength: Dumbbells were punched out from the pinch-off (PO) part of the bottle in a direction vertical to the PO and in the horizontal direction of the bottle from the side of the body. It was measured at a pulling speed of ˜4 m and expressed in breaking energy kJ / m ² . Each of them has an arithmetic mean value of n = 10 as data. The test results are shown in Table 2. Drop impact strength: About full-filled with water, left at 5 ° C for 24 hours, then dropped from a height of 1.2 m, the number of broken pieces is vertical drop with the bottom of the bottle downward, horizontal drop with handle Each of 24 pieces was examined.

[0017]

[Table 2]

As a result, in the case of the conventional adhesive (Comparative Example 2), it was sufficiently practicable when the bottle mower had a thick wall of 70 g, but the weight was reduced to 64 g as in the example here. In this case, the drop strength is insufficient. In particular, cracks such as tears will occur at the thin portion of the body. When the interface of EVOH particles in the main layer of the recovery material-containing layer was observed with an electron microscope, peeling was often observed at the fractional particle interface in Comparative Examples 1 and 3, and there was almost no peeling in the present invention.

Examples 2 to 6 and Comparative Examples 4 to 6 Here, the effect of MFR on the moldability of the metallocene adhesive and the container performance, and the drop strength improving effect particularly when the logo mark is arranged on the bottle container. It was confirmed. Various metallocene adhesives having a grafting rate modification by the maleic anhydride unsaturated carboxylic acid or its derivative shown in Table 3 of about 0.5%, and the same EVOH as the above embodiment as a barrier resin.
Is used as a base resin for the high pressure method LDPE (MRF 0.7 g /
L from the outer layer of the container using 10 min, density 0.924)
DPE / AD / EVOH / AD / LDPE + REG / L
DPE (layer ratio: 15/3/5/3/54/20 wt%)
4 kinds of 6 with the internal volume of 1100 ml and the weight of 24 g
A multi-layer thin wall bottle was rotary blow molded at a rate of 70 bottles per minute. In this bottle, logo marks are arranged on the front and back of the bottle body mold. Table 3 for moldability
Described in.

[0020]

[Table 3]

+ Metallocene adhesive with graft ratio modification of 5% by unsaturated carboxylic acid or its derivative The following items were evaluated for the obtained bottles. Transparency: According to JIS K7105, the haze was evaluated as the transparency on the side wall of the bottle, and the haze was 0.5 mm.
The value converted into the thickness of is shown. Barrier properties: Bottle surface area 620 cm ² , approx.
10 ml of pure water was charged, the inside of the bottle was completely replaced with nitrogen, the change in the oxygen concentration inside was measured in an atmosphere with a relative humidity of 80%, and the oxygen permeation amount cc / day atm m ² was calculated. Drop impact strength: About full-filled with water, left at 5 ° C for one day and then dropped from a height of 1.5m, and count the number of breaks vertically drop with the bottle bottom down, horizontally with the logo mark down. Each of 24 pieces was examined.

[0022]

[Table 4]

* The fifth pinhole-like crack at the 5th time, ** it cracks like a crack at the origin of the logo mark. As a result, regarding the moldability, it is found that the MFR of the metallocene adhesive needs to be within the appropriate range in relation to the base resin and the barrier material. If the MFR is too low, the resin pressure becomes significantly higher and unbalanced as compared with the other layers, the uneven thickness of the bottle becomes large, and the drop strength decreases. Also, if the MFR is too high, EVO
The uneven thickness of the H layer becomes large, and in addition to the drop strength being lowered, the barrier property is also lowered (Comparative Examples 5 and 6). Also, conventional LD
The PE-based adhesive has good moldability, but its transparency is lowered, and drops and breaks such as tearing with a logo mark become conspicuous. (Comparative example 4). The metallocene LL-based adhesive stabilizes the EVOH dispersion in the layer containing the recovered resin, resulting in improved transparency and improved drop strength. In particular, prevent the logo mark etc. from becoming the starting point of destruction. In the present invention 5, a method in which an adhesive material having a graft ratio modified by a high unsaturated carboxylic acid or a derivative thereof is polymerized in advance and then diluted with a base resin is used, but the recovered resin (regrind, R
Since the dispersibility of EG) is poor, the transparency tends to deteriorate underground. Either method should be selected in terms of cost performance, and this method is effective when adjusting liquidity.

Examples 7 to 11 and Comparative Example 7 Here, an example of a multilayer container having a layer structure in which a metallocene adhesive material or a recovered resin containing the same is used in various forms is shown. As an adhesive, a metallocene LL-based density consisting of ethylene and octene-1, 0.905, M
FR1.5, molecular weight distribution Mw / Mn 4.0, maleic anhydride graft modification rate of 0.8% by weight, LDPE having excellent gloss and transparency on the outer layer: density 0.918, MFR 0.8,
Using a block PP: ethylene content of 6.8% and MFR of 1.3 g / 10 min as a rigid resin for the inner layer, a cylindrical multi-layer bottle having an inner capacity of 1050 ml and a moistening amount of 42 g with the layer constitution of Table 5 is discharged at 150 kg / h. Amounts were rotary blow molded (Examples 7-10). In Comparative Example 7,
An ordinary LLDPE: density 0.903, MFR 1.5, molecular weight distribution Mw / Mn 3.2, maleic anhydride graft modification rate of 0.8% by weight was used as an adhesive material, and a bottle having the same configuration as that of Example 7 was prepared.

[0025]

[Table 5]

The following items were evaluated for the obtained bottles. Drop impact strength / delamination: Filled with water almost completely and left at 5 ° C for 24 hours, then dropped from a height of 1.5 m to drop the number of broken pieces vertically with the bottle bottom down, horizontally with the logo mark down. , And 20 were examined. Furthermore, the drop survivor bottle was observed for the presence or absence of layer separation.

[0027]

[Table 6]

* Around the logo mark As a result, in any case, in Comparative Example 7, it was necessary to change the extruder setting conditions, and it was possible to perform molding without any particular problems, except that some finish defects at the mouth part occurred. there were. Conventional LL
When the DPE-based adhesive was used, although the number was small, there was a tendency for pinhole-like leakage at the bottom pinch-off. In addition, it was found that delamination with a large area is generated, and delamination occurs even with simple bottle handling, which is defective in storage of the content product. In the present invention, although some delamination was caused by severe drop (Example 7), practical performance was satisfactory in all cases.

Examples 12 to 14 Here, the effect of adding a small amount of the metallocene adhesive to the recovered resin layer was shown. Density of maleic anhydride graft modification and graft ratio modification with 0.5% by weight of unsaturated carboxylic acid or its derivative based on the same metallocene LL of ethylene-hexene-1 copolymer as the metallocene adhesive. 0.920, MFR
1.1, molecular weight distribution Mw / Mn of 4.8 is used,
4M6L content of each material composition shown in Table 7 1700ml,
I made a 60g bottle with a handle. The same base resin as in Example 1 above, HDPE: Density 0.952
EVOH containing g / cm ³ , MFR 0.7 g / 10 min and ethylene containing 32 mol was used as a barrier material. Here, when the recovered resin (REG) single layer of the inner layer was initially used, the discharge amount was not stable, so that the one re-pelletized at 210 ° C. was used (Example 12). In this case, the adhesives of the present invention were added in an amount of 3% and 5%, respectively (Examples 13 and 14).

[0030]

[Table 7]

Drop impact strength: 5
After standing at ℃ for 24 hours, it is dropped from 1.5 m, which is higher than 1.2 m in the previous example, and the number of broken pieces is vertically dropped with the bottom of the bottle down, and the handle is horizontally dropped down. 24 lines were examined.

[0032]

[Table 8]

In all cases, the moldability was good. In particular, re-pelletizing stabilized the discharge and reduced the fluctuation of the bottle mass. It is possible to further reduce the weight as compared with Example 1, and the drop strength is also improved by one rank. This is also reflected in the tensile impact strength of the bottom PO part. Further, the addition of an adhesive to the REG layer improved the haze from around 80% to around 70% (Examples 13 and 1).
4).

Example 15 In this example, a PET resin is used as the barrier resin in the outermost layer. Maleic anhydride graft modification based on metallocene LL consisting of octene-1 as an α-olefin as an adhesive material Density of graft ratio modification with unsaturated carboxylic acid or its derivative of about 0.5% by weight 0.890, MFR 1. 3, molecular weight distribution Mw / Mn3.
8 is used, and PET is used as the outermost gloss resin layer.
G: IV (intrinsic viscosity) value 0.8 dl / g, terephthalic acid,
Amorphous copolyester from cyclohexanedimethanol (CHDM), block PP as a base resin (Example 15, ethylene content 8.2, MFR 1.5), H
DPE (Example 16, density 0.953 g / cm ³ , MFR 0.6
g / 10min), PETG / Tie / PP + REG / PP, PET
G / Tie / HDPE + REG / HDPE 4M4L (composition ratio: 20/5/45/30% by weight) bottle weight 50g, height 185mm, trunk major axis / minor axis 92
A pump size bottle with an elliptical cross section of / 68 mm and full-filled internal volume of 765 ml was produced by rotary blow molding at 50 bottles per minute. All of the bottles had good moldability, the multi-layer bottle had good adhesiveness, and the content resistance was excellent.

[0035]

By using a metallocene adhesive having excellent interlaminar adhesion and material strength in a multi-layer container, a lightweight multi-layer container excellent in drop strength and the like can be provided. In addition, the scrap material generated by the production of a large number of multi-layer containers is collected and reused in multi-layer containers to solve environmental problems,
It has the excellent effect of making a multi-layer container that is lightweight and has excellent drop strength.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of Example 1 of the multilayer container according to the present invention.

FIG. 2 is an explanatory view of Examples 2 to 6 of the multi-layer container of the present invention.

FIG. 3 is an explanatory diagram of Example 7 of the multilayer container according to the present invention.

[Fig. 4] Examples 9, 10, 13, 1 of the multilayer container of the present invention
It is explanatory drawing of FIG.

FIG. 5 is an explanatory diagram of Example 8 of the multilayer container according to the present invention.

FIG. 6 is an explanatory view of Example 12 of the multilayer container of the present invention.

FIG. 7 is an explanatory diagram of Example 15 of the multilayer container according to the present invention.

[Explanation of symbols]

1 Layer containing base resin 2 Layer containing base resin and recovered resin 2a Layer containing base resin and recovered resin and further metallocene adhesive 3 Metallocene adhesive layer 4 Barrier resin layer 5 Layer containing base resin 6 Recovery Resin layer 7 PET resin layer

Continued front page    (72) Inventor Masahiko Otsuki             1-8 East Shimotaniya-cho, Tsurumi-ku, Yokohama-shi, Kanagawa             Yoseikan Co., Ltd. Engineering Division Tsurumi Branch Room F-term (reference) 3E033 AA02 BA14 BA15 BA16 BA17                       BA21 BB01 BB08 CA03 CA20                       FA03                 4F100 AK01C AK01D AK02B AK04A                       AK05A AK05C AK06A AK06C                       AK07A AK07C AK07E AK41B                       AK46B AK62A AK62C AK68A                       AK68C AK69B AL04C AL05C                       AL07C AR00B AT00A DA01                       GB16 JA06C JA13C JA20C                       JD02B JK01 JK06 JK10                       JL16C JL16D YY00C YY00D

Claims (8)

[Claims] 1. At least A. A layer containing a base resin (a), and B. A barrier resin (b) layer, and C.I. A multilayer container comprising a layer containing an adhesive resin (c) made of a graft acid-modified resin of an ethylene-α-olefin copolymer polymerized by a metallocene catalyst. 2. At least one layer is (a), (b),
The multilayer container according to claim 1, which has a recovered resin layer containing (c). 3. The base resin (a) is a propylene resin,
Low density polyethylene, high density polyethylene, ethylene-
The multi-layer container according to claim 1 or 2, which is one or more resins selected from a vinyl acetate copolymer and an ethylene-α-olefin copolymer. 4. The barrier resin layer (b) is a layer containing one or more resins selected from ethylene-vinyl alcohol copolymers, polyamide resins, polyester resins and cyclic polyolefin resins. The multi-layer container according to any one of 3 above. 5. The adhesive resin (c) has a density of 0.93 g / cm ³
Hereinafter, MFR is 0.5 to 10.0 g / min, the graft modification rate with an unsaturated carboxylic acid or its derivative is 0.3 to 5% by weight,
The multi-layer container according to any one of claims 1 to 4. 6. The recovery resin layer is a layer in which the contents of the adhesive resin (c) and the barrier resin (b) are adjusted to a weight ratio of 1: 1 to 1:10. The multi-layer container described in the item. 7. The layer containing the adhesive resin (c) comprises a layer comprising a mixture of the adhesive resin (c) and the base resin (a), a layer comprising a recovered resin, and a mixture of the recovered resin and the adhesive resin (c). 7. Any one selected from the following layers:
The multilayer container according to any one of 1. 8. The multi-layer container according to claim 1, wherein the base resin (a) layer comprises a layer made of an ethylene resin and a layer made of a propylene resin.