JPH02155735A - Multiple layer cotainer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multilayer container that has excellent impact resistance and solvent permeation resistance.

[Conventional technology]

Conventionally, containers for solvents and the like have generally been made of metal or glass, but in recent years, containers made of plastic have come into use.

Plastic containers have various advantages, such as being lightweight, having excellent impact resistance, not requiring treatment such as rust prevention, and having a high degree of freedom in design. Polyolefin is suitable as a plastic that satisfies these characteristics, and is used in a wide variety of fields such as various industrial chemical containers, kerosene cans, drums, and gasoline tanks. However, a drawback of polyolefin containers is that they have poor solvent permeation resistance. In order to improve this drawback, a multilayer container using a barrier resin such as polyamide is considered. Since polyamide has no affinity with polyolefin, a container exhibiting good adhesiveness cannot be obtained unless an adhesive layer is interposed between the two layers when multilayering. Furthermore, in the case of containers for solvents such as alcohol, polyamide cannot be used for the inner layer because it swells. Furthermore, it cannot be used as an outer layer due to impact resistance problems. Therefore, polyamide is positioned as an intermediate layer, but in this case, the container must have a complicated structure consisting of five layers of three types: polyolefin/adhesive/polyamide/adhesive/polyolefin. The three-type, five-layer method requires at least three extruders and a complicated die structure, making it extremely complicated in terms of equipment and manufacturing.

[Problem to be solved by the invention]

The object of the present invention is to provide a multilayer container that exhibits good adhesion without intervening an adhesive layer, unlike such conventional methods.

[Means for solving problems]

In view of the above-mentioned current situation, the inventors of the present invention have made extensive studies and have found a multilayer container with a two-layer, three-layer structure that does not require an adhesive layer, and have completed the present invention.

That is, in the present invention, the inner layer and the outer layer are a mixture of a polyolefin and a modified polyolefin grafted with one or more compounds selected from unsaturated carboxylic acids or derivatives thereof; It consists of a composition in which the content of at least one compound selected from carboxylic acids or derivatives thereof is 0.005 to 0.5v1%, and the intermediate layer is selected from polyamide 50 to 95wt% and unsaturated carboxylic acids or derivatives thereof. Modified polyolefin 5 to 5, which is grafted with at least one kind of compound and has a grafting rate of 0.01 to lv1%
The present invention relates to a multilayer container characterized in that it is made of a modified polyamide mixed with 0w1%.

The polyolefin used in the present invention refers to at least one of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, and the like. Among these polyolefins, high-density polyethylene (hereinafter abbreviated as HDPE) is preferred in terms of moldability, strength, and impact resistance.

The modified polyolefin used in the present invention refers to a polyolefin grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof.

Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc., and derivatives of unsaturated carboxylic acids include:
Acid anhydrides, esters, amides, imides and metal salts, such as maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,
Butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monoethyl itaconate, diethyl itaconate, acrylamide, methacrylamide, maleic acid. Acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N1N-diethylamide, maleic acid-N-monobutylamide, maleic acid-NSN-dibutylamide, fumaric acid amide, fumaric acid diamide, fumaric acid -N-
Monoethylamide, fumaric acid N, N-diethylamide, fumaric acid N-monobutyramide, fumaric acid N, N-
dibutylamide, maleimide, N-butylmaleimide,
Examples include N-phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, and the like. Among these, maleic anhydride is most preferred.

Methods for grafting these monomers onto polyolefins include mixing polyolefins, monomers, and radical generators such as peroxides, and grafting them by melt extrusion; or grafting monomers and monomers onto polyolefins suspended or dissolved in an appropriate solvent. Examples include a method of grafting by adding a radical initiator and heating.

In the present invention, the composition used for the inner layer and the outer layer refers to a mixture of a polyolefin and the above-mentioned modified polyolefin, and although the mixing ratio varies depending on the degree of modification of the modified polyolefin used, it is possible to mix the polyolefin and the modified polyolefin. The content of at least one compound selected from grafted unsaturated carboxylic acids or derivatives thereof in the composition after mixing is 0.005 to 0.
．． 5v1%, preferably 0. O1~0. The mixing ratio is such that lv1%. This content is 0,005v1%
If it is less than 0.5v1%, the adhesion is insufficient, and if it exceeds 0.5v1%, it is unfavorable in terms of price. In addition, the grafting rate of the modified polyolefin used in the intermediate layer is 0.01 to 1.01%,
Preferably it is in the range of 0.05 to 0.5v1%. O,
If it is less than QIwt%, the compatibility with the polyamide is insufficient, and if it exceeds 1.0w1%, the compatibility with the polyamide is sufficient, but it increases the cost, which is not preferable. In addition, the melt flow rate (113K) of the composition used for the inner layer and outer layer is
? Measured according to 210 at a temperature of 190°C and a load of 2.16 kg. Hereinafter, it will be abbreviated as VFR. ) is 0.01 to 10.
θg/10m1n is preferable, and 0.02 to 3.0x/I
f1min is more preferable. -01g/l0IIli
If it is less than 0, the fluidity during melting may deteriorate, and if it exceeds 10, Of/10 nin, the drawdown property may become large and it may become difficult to mold. On the other hand, the MFR of the modified polyolefin used in the intermediate layer after grafting is 0. Old to 10.0 g/10 m1n is preferable, and θ, [12 to 5. More preferred is the Og/lhi port. 0.01! If it is less than 10.0 g/10 nin, the fluidity during melting may deteriorate, and if it exceeds 10.0 g/10 nin, dispersion may be reduced during melt-kneading with the modified polyamide.

The polyamide used in the present invention is a linear polymer having an acid amide bond -CONH-, and is a linear polymer having an acid amide bond -CONH-.
6, nylon-6, 6, nylon-6, 10, nylon-11, nylon-12, and blends or copolymers thereof.

Among these nylons, nylon-6 is preferred in terms of moldability and strength.

The modified polyamide in the present invention refers to a mixture of the above-mentioned polyamide and modified polyolefin, and the mixing ratio of polyamide and modified polyolefin is as follows:
The content ranges from 0 to 95 wt%, and from 5 to 50 wt% of the modified polyolefin. If the proportion of the modified polyolefin is less than 5w1%, interlayer adhesion will decrease, and if it exceeds 50wt%, solvent permeation resistance will decrease, which is not preferable.

The modified polyamide MFR (Its
According to K 7210, temperature 230℃, load 2.16kg
Measured at. ) is 0.01 to 5.0/I(la
In is preferred. 0.01! /1 OIlin, fluidity during melting may be poor, and 5.0g/10
If m1n is exceeded, workability may deteriorate.

Examples of methods for mixing polyolefin and modified polyolefin, and polyamide and modified polyolefin include tri-blending using a conical blender or ■blender, or melt blending using a mixer such as an extruder, kneader, or Banbury. Melt blends are preferred in this respect.

Any method may be used to mold the multilayer container using these resins, but coextrusion blow molding is preferred. Examples of the method include an extrusion method and a single accumulator method. For large containers, a single accumulator method is suitable, and for small containers, an extrusion method is suitable. As for the molding conditions, the resin temperature of the modified polyolefin mixture used for the outer layer and inner layer is 220 to 23
23 at 0°C and the resin temperature of the modified polyamide used for the intermediate layer.
It is preferable to set the temperature to 0 to 250°C.

In this way, it is possible to obtain a multilayer container with good impact resistance and solvent permeation resistance, which is composed of two types and three layers.

〔Example〕

Next, examples of the present invention and comparative examples corresponding thereto will be described, but the present invention is not limited thereto.

[Example 1] Accumulator type blow molding machine (90011+1φ.

30Mφ) was used for molding.

MFR is achieved by grafting 0.2v1% of boron hard 8600^ (manufactured by Tosoh Corporation) and maleic anhydride onto HDPE.
is 0.35g/l [1ml1n of modified polyolefin 9
:1 and melt-mixed using a 65sφ extruder.

The content of the unsaturated carboxylic acid or its derivative thus obtained was 0.02 w1%, and the MFR was 0.03 mm/!
The composition of 0nio was transferred to an extruder for inner and outer layers (90 mmφ
) was supplied to the multilayer die. On the other hand, the modified polyamide used for the intermediate layer is nylon-6 (!030B).

Ube Industries Co., Ltd.) and VFR are tl, 35g/I (
lrain HDPE, Poron Hard 8300^ (manufactured by Tosoh Corporation) and 0.2v1% maleic acid grafted thereto were melt-mixed in a ratio of 6=4 using a 651111φ extruder. The MRF obtained in this way is 0.3
5/Ihn's modified polyamide in an extruder for intermediate layer (30
mmφ) to the multilayer die. The molding temperature is such that the resin temperature is 230°C for the modified polyolefin mixture for the inner and outer layers.
The temperature was set to 240°C for the polyamide for intermediate layer, and multilayer blow molding was performed. The multilayer container obtained from the above has two types and three layers, and its thickness is 2 mm for the outer layer and 0.1 mm for the middle layer.
The inner layer was 2-. The outer container was a 40 yen cylindrical plastic drum. The interlayer adhesive strength, low temperature drop strength, and gasoline permeability of the obtained plastic drum were measured, and the results are shown in Table 1. Here, interlayer adhesion strength (
Unit 0kg/1OnII11) is width 10m1 length 12
The test piece of No. 0 was measured by T peeling at a peeling speed of 200 mm/rain. Low-temperature drop strength (unit, number of non-destructive samples (pieces) / number of samples (pieces)) was determined by adding 100% 50% ethylene glycol aqueous solution, leaving it in a low-temperature room at 40°C for 24 hours, and then dropping it from a height of 10 m. It is shown by the number of samples at time and the number of non-destructive samples. Gasoline permeability (unit,
g/dxyl is 50% gasoline in a plastic drum
After filling and aging at 40°C for 30 days, gasoline permeability was measured.

(Example 2) Nylon-6 (1030B, manufactured by Ube Industries, Ltd.) as the intermediate layer and lIDP with a VFR of 0.35 g/l0m1n
E (-Boron Hard 8300^, manufactured by Tosoh Corporation)
and 0.2v1% maleic anhydride grafted onto it in a ratio of 7:3 using a 65+nn+φ extruder!
Multilayer blow molding was performed in the same manner as in Example 1 except that modified polyamide with a JFR of 0.40 g/10 cylinders was used.

[Example 3] Nylon-6 (+030B, manufactured by Ube Industries, Ltd.) and lIDP with a VFR of 0.35 g/1Onin as the intermediate layer
To E, Poronhard 83QOA (manufactured by Tosoh Corporation) was grafted with 0.2w1% maleic anhydride.
:Melt mix in a 65mmφ extruder at a ratio of 2 to MFII
Multilayer blow molding was performed in the same manner as in Example 1 except that modified polyamide with a diameter of 0.451/10 mm was used.

[Example 4]) IDPE was grafted with boron hard 8600^ (manufactured by Tosoh Corporation) and maleic anhydride at 0.4w1% to form MF.
9 modified polyolefin with R of 0.35 g/1Onin
:1 in a 65 mm diameter extruder.

The content of the unsaturated carboxylic acid or derivative thereof thus obtained is 0. Q4v1%, MFII is 0.03/1
All (
Multilayer blow molding was performed in the same manner as in Example 1.

[Comparative Example 1] VFR was 0.03g710+lin instead of the modified polyolefin mixture used for the outer layer and inner layer in Example 1.
Multilayer blow molding was performed in exactly the same manner except that Poron Hard 8600 (manufactured by Tosoh Corporation) was used for the unmodified HDI'E.

[Comparative Example 2] Multilayer blow molding was performed in exactly the same manner as in Example 1, except that only unmodified nylon-6 (10308 manufactured by Ube Industries, Ltd.) was used instead of the modified polyamide used for the intermediate layer. Ta.

[Comparative Example 3] In Example 1, nylon-6 (1030B) was used as the intermediate layer.
(manufactured by Ube Industries, Ltd.) and VFR of 0.35ff/l.
Poronhard 8300A (manufactured by Tosoh Corporation) was grafted with 0.2v1% maleic acid to IDPE (of 0nin), and was melt-mixed in a 65mmφ extruder at a ratio of 4=6, resulting in modification with a VFR of 0.25g/IOn+in. Multilayer hollow molding was performed in exactly the same manner except that polyamide was used.

[Comparative Example 4] In Example 1, boron hard 8 was added to II D Pε instead of the modified polyolefin mixture used for the outer layer and inner layer.
600^, manufactured by Tosoh Corporation) with 0.0% maleic anhydride.
02wt% grafted and MFR is 0.03g/10IIl
Multilayer hollow molding was carried out in exactly the same manner except that modified polyolefin (in) was used.

〔Effect of the invention〕

As is clear from the above description, according to the present invention,
Even without using an adhesive layer, it is possible to obtain a multilayer container with good interlayer adhesion, excellent impact resistance, and solvent permeation resistance.

In addition, since no adhesive layer is required, only two extruders are required, and the die structure is simpler than the three-layer, five-layer method, reducing equipment and processing variable costs. Can be done.

Claims (1)

[Claims] (1) The inner layer and the outer layer are a mixture of a polyolefin and a modified polyolefin grafted with at least one compound selected from an unsaturated carboxylic acid or its derivative; It consists of a composition in which the content of at least one compound selected from derivatives is 0.005 to 0.5 wt%, and the intermediate layer is 50 to 95 wt% of polyamide and at least one selected from unsaturated carboxylic acids or derivatives thereof. and the grafting ratio is 0.0.
1-1 wt% modified polyolefin 5-50 wt%
A multilayer container characterized by being made of a modified polyamide mixed with.