GB2251845A

GB2251845A - Multilayer container

Info

Publication number: GB2251845A
Application number: GB9127161A
Authority: GB
Inventors: Kazuhiro Takanashi; Eishin Bannai; Masahito Hanaoka
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 1990-12-21
Filing date: 1991-12-20
Publication date: 1992-07-22
Anticipated expiration: 2011-12-20
Also published as: GB9127161D0; GB2251845B; JP3012340B2; HK193896A; MY107670A; JPH04220499A

Abstract

A multilayer container for storing liquid bleach comprises an outer layer (A) formed by a thermoplastic resin(s) including a pigment(s) and an inner layer (B) formed by a thermoplastic resin(s), with no pigment located on the inside of the layer (A). At least one pigment-free layer may be located between the layers (A) and (B). <IMAGE>

Description

MULTILAYER CONTAINER The present invention relates to a liquid bleach disposed in a multilayer container and stably stored.

An aqueous solution of a hypochlorite or hydrogen peroxide has been widely used heretofore for bleaching clothes, removing dirt from hard surfaces of tableware and articles in a toilet room or a lavatory and removing moulds, because it is a liquid which is convenient to use.

Such liquid bleach is usually in the form of a 0.5 to 10 weight % aqueous solution disposed in a resin bottle made of a flexible plastic material with a high tightness, such as polyethylene, and is readily available on the market as a household liquid bleach. In addition, liquid bleaches are available on the market in the form of an aqueous solution of other inorganic peroxy acids or organic peroxy acids or dispersions thereof in a solvent.

Liquid bleaches sometimes decompose depending on the storage conditions giving off an unpleasant odour or causing deformation of the bottle when gas.is given off in large amounts. In view of these problems investigations have been made on the composition of the liquid bleaches for the purpose of improving storability.

For example, in order to improve the storability of an aqueous hypochlorite solution, U.S.P. No.4029591 discloses that the addition of a specified polyoxyethylene alkylphenol sulfate is effective and Japanese Patent Laid-Open No.89800/1987 discloses that the addition of a specified perfume component is effective.

Further investigations have been made in an attempt to improve the storability of an aqueous hydrogen peroxide solution. Japanese Patent Publication No.775/1965 discloses a weakly acidic liquid bleach comprising acid sodium pyrophosphate, neutral sodium pyrophosphate and neutral potassium pyrophosphate having a high storability; U.S.P. No.3811833 and G.B.P.

No.1419184 disclose a stable liquid bleach comprising an organic acid selected from among alkylidenediphosphonic acids, ethylenediamine-tetraacetic acid, diethylenetriaminepentaacetic acid and nitrilotrimethylenephosphonic acid, a soluble tin salt and an ammonium salt and having a pH of 0.5 to 7; U.S.P.

No.4363699 and G.B.P. No.1524013 disclose a stabilizer for hydrogen peroxide which comprises poly-ahydroxyacrylic acid; Japanese Patent Laid-Open No.10309/1979 discloses that the decomposition of hydrogen peroxide is inhibited at a pH of 4 to 6 with a hydrophilic liquid substance obtained by adding water to a magnesium compound and an acid to form a complex by neutralization; U.S.P. No.4238192 and E.P.No.13886 disclose a stable liquid bleach having a pH of 1.8 to 5.5 which comprises an acid selected from organic acids, phosphoric acid and boric acid and a nitrogen compound; Japanese Patent Laid-Open No.76161/1980 discloses that a synergistic stabilization effect can be obtained by incorporating a poly-a-hydroxyacrylic acid salt into an alkaline hydrogen peroxide bleach containing a polyphosphate as the stabilizer; Japanese Patent Laid Open No.154457/1982 discloses a stabilizing assistant for a hydrogen peroxide bleach which comprises a copolymer of acrylic acid with an acrylate and/or polyethylene glycol methacrylate; and Japanese Patent Laid-Open No.

185797/1987 discloses a stabilizer for hydrogen peroxide bleach which comprises a poly-a-hydroxyacrylic acid salt and an organic phosphonic acid salt.

However, the liquid bleaches are also unstable to light and therefore, a liquid bleach composition having a high stability on its own is insufficient for selling as a commercial product. Thus liquid bleach compositions are placed on the market in highly light-screening, thick-walled, coloured resin bottles.

Although no problem arises when liquid bleach products are kept in a store or a dark, cold place, it has been found recently that a pigment usually incorporated into the resin from which the bottle is made for the purposes of screening light and improving the appearance of the bottle to appeal to the consumer accelerates the decomposition of the contents of the bottle, i.e. a liquid bleach by giving off a gas when the bottle is exposed to high-temperatures for a long period of time.

However, the interaction between the pigment incorporated into the resin of the bottle and the liquid bleach contained in the bottle has never been discussed heretofore and no improvement for inhibiting gas production has been attempted.

A multi layer container has been used for food and drink and occasionally for the purpose of preventing contamination of the food and drink by the inorganic filler incorporated into the resin of the container. For example, Japanese Patent Laid-Open No.253539/1985 discloses a multi layer container which comprises an outer layer made of a resin composition composed of 20 to 80% by weight of inorganic filler(s) and 80 to 20% by weight of thermoplastic resin(s) and a inner layer made of a resin composition composed of a polyethylene and a polypropylene and no inorganic filler. However, a multilayer container has not been used for detergents and bleaches.

An object of the present invention is-to provide a liquid bleach disposed or filled in a container or vessel capable of effectively inhibiting decomposition of the liquid bleach, even under severe conditions.

After intensive investigations it has been found that the object of the present invention can be attained by using a thermoformed container made of a specified resin laminate.

The present invention provides a liquid bleach disposed or filled in a multi layer container comprising a liquid bleach composition and a thermoformed multilayer container, the thermoformed multilayer container having an outer layer (A) comprising a thermoplastic resin(s) and a pigment(s) and an inner layer (B) comprising a thermoplastic resin(s) and no pigment formed on the inside of the layer (A).

The ratio of the thickness of the layer (A) to that of the layer (B) is preferably 99.99 : 0.01 to 50 : 50, more preferably 99 : 1 to 55 : 45.

It is preferably that the layer (A) comprises 99 to 80% by weight of the thermoplastic resin(s) and 1 to 20% by weight of the pigment(s).

Furthermore, it is preferable that the pigment is selected from the group consisting of a pigment of phthalocyanine group, that of azo group, that of metal oxide, carbon black and a mixture thereof.

The thermoplastic resin used is preferably selected from the group consisting of a polyolefin and a polystyrene.

The thermoplastic resin used is preferably a polyethylene, more preferably a low-density polyethylene.

The liquid bleach composition is preferably an aqueous hydrogen peroxide solution.

Furthermore, the present invention provides a thermoformed multi layer container for housing a liquid bleach composition having an outer layer (A) comprising a thermoplastic resin(s) and a pigment(s) and an inner layer (B) comprising a thermoplastic resin(s) and no pigment formed on the inside of the layer (A).

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawing which is given by way of illustration only.

Fig.1 is a partially broken front view of the multilayer container of the present invention.

The thermoplastic resins used for forming layer (A) are not particularly limited and include those which can be molded under ordinary conditions of thermoforming bottles. Examples of the thermoplastic resins include polyolefins such as polyethylenes (e.g. highdensity polyethylene, low-density polyethylene and linear low-density polyethylene) and polypropylene (e.g. homopolymers, block copolymers and random copolymers), polyvinyl chloride, polystyrene, polyesters, acrylonitrile/styrene resin, styrene/butadiene block copolymers and mixtures thereof. The polyolefins and polystyrene are particularly preferred in the present invention. When a polyolefin resin is used, polyethylene, polypropylene and polybutene resins can be used either alone or in the form of a mixture.When the multilayer containers of the present invention are to be continuously produced on a large scale by a thermoforming method such as blow molding, it is advantageous to use resins of the same family.

The thermoplastic resins used for forming layer (B) are not particularly limited and those described above for layer (A) can be used. Although the thermoplastic resin of layer (A) may be different from that of layer (B), they are preferably made of the same one.

Various pigments can be used in layer (A).

Organic pigments usable therein include azo, anthraquinone, phthalocyanine, perinone, perylene, quinacridone, dioxazine, thioindigo and isoindolinone pigments and mixtures thereof. Inorganic pigments usable therein include metal oxides such as red iron oxide, titanium white, titanium yellow, fired pigment green, chromium oxide, cobalt blue, silica and alumina; sulfides such as cadmium yellow and cadmium red; silicates such as ultramarine; chromates such as chrome yellow and chromium vermilion; carbons such as carbon black; clays such as talc, kaolin and clay; inorganic salts such as calcium carbonate, magnesium carbonate, calcium sulfite, calcium sulfate, aluminum hydroxide, barium sulfate and magnesium carbonate; and mixtures thereof.In particular, phthalocyanine, azo and metal oxide pigments and mixtures thereof have excellent weather resistance, light-screening properties, thermal resistance, color-developing properties and chemical resistance, so that they are preferably used.

When a phthalocyanine or azo pigment is used, the variety or form thereof is not particularly limited.

For example, highly purified pigments or those heat-treated to remove impurities therefrom can be used and, in addition, those containing a small amount of impurities can also be used.

When titanium white among the metal oxides is used in combination with the organic pigment, the titanium white usually refers to titanium dioxide (TiO2), which may be one containing a small amount of titanium monoxide (TiO) or dititanium trioxide (Ti2O) as well as a small amount of impurities such as silica, alumina, heavy metals and metal oxides, which pose no problem at all. The form of the titanium oxide is not particularly limited.

A material for layer (A) in the present invention is prepared by kneading 99.99 to 50% by weight, preferably 99 to 80% by weight, of the thermoplastic resin and 0.01 to 50% by weight, preferably 1 to 20% by weight, of the pigment. If necessary, various antioxidants, ultraviolet absorbers, antistatic agents and lubricants can be added to the material for layer (A).

A material for layer (B) in the present invention is a chip or a sheet made of the thermoplastic resin, for example. If necessary, various antioxidants, ultraviolet absorbers, antistatic agents and lubricants can be added to the material of layer (B).

The multilayer container or vessel used in the present invention has the pigmented thermoplastic resin layer (A) and the pigment-free thermoplastic resin layer (B), and layer (B) is disposed inside layer (A). Namely, layer (B) is served as the inner layer. The multilayer container used in the present invention may have at least one layer between layer (A) and layer (B).

Fig. 1 shows one example of the two-layered container of the present invention having layer (B) disposed inside layer (A).

The thickness ratio of layer (A) to layer (B) is not particularly limited. It is suitably determined depending on the variety and amount of the thermoplastic resin(s) and pigment(s) used. As for the layer thickness ratio of a two-layered container, that of layer (A) to layer (B) is preferably 99.99 : 0.01 to 50 : 50, more preferably 99 : l to 55 : 45, the thickness of the total layers being 100.

The average wall thickness of the multilayer container is usually about 0.5 to 1.5 mm.

The container used in the present invention can be produced by various methods which are not particularly limited. For example, a laminated sheet comprising layers (A) and (B) can be thermoformed into an intended container by blow molding and the like.

The liquid bleach composition used in the present invention includes those comprising an ordinary aqueous solution of a hypochlorite or hydrogen peroxide as the bleaching base and other ordinary components. The composition is also not particularly limited.

The following Examples will further illustrate the present invention, which by no means are intended to limit the scope of the present invention.

(Example 1) Bottles made of a resin and a resin composition and having a layer thickness ratio as specified in Table 2 were formed to give a multilayer container for liquid bleach having the shape shown in Fig.1. Each of the bottles thus obtained was filled with a liquid bleach composition specified in Table 1 and tightly sealed. The bottles were examined by the following test method.

(Test Method) 100 ml of a liquid bleach composition shown in Table 1 was poured into each bottle (capacity: 1150 ml, average wall thickness: 1 mm) listed in Table 2 and the bottle was tightly closed and stored under the following conditions: (1) 500C for 30 days, or (2) exposure to solar rays for 30 days (the maximum temperature: 300C, the minimum temperature: 220C).

After storage tests, the samples were taken out and those subjected to the test condition (1) were examined with the naked eye for any bulging or deformation of the bottles, while those subjected to the test condition (2) were examined for a change in the smell of the liquid bleach compositions in the bottles.

The criteria for measuring the bulge of the bottles and change in the smell of the liquid bleach compositions were given below. 10 bottles were used in each test and the results were given in terms of the number of samples evaluated to be o, 4 or x.

Criteria of evaluation: (1) Bulge of the bottle: o: no change a: the bottom of the bottle slightly bulged but the bottle stood stable.

x the bottom of the bottle slightly bugled and the bottle could not stand stable.

(2) Change in smell: o: none A: slight x: discernible Table 1 Bleach composition

Hydrogen peroxide 5 Sodium linear alkylbenzene- 0.5 sulfonate*1) Polyoxyethylene alkyl ether*2) 2 Dequest 20103) 0.1 NaOH in a minute amount4) Fragrance or Perfume 0.05 Deionized water the balance pH 4 (unit: wt. %) *1) alkyl: C12 *2) alkyl: C12 to C14, ethylene oxide (8 mol) adduct *3) l-hydroxyethylidene-l,l-diphosphonic acid mfd. by Mitsubishi Monsanto Chemical Co.

*4) an amount necessary for adjusting the pH to 4. Table 2

Comparative Present invention 1 2 3 4 5 6 7 Layer (B) LDPE*1) 100 parts 100 100 100 100 100 by wt.

LDPE*1) 95 parts 95 95 95 80 99 Resin by wt.

compo- titanium white 5 parts 5 5 4.5 18 1 sition Layer (A) by wt.

cyanine green 0.25 carbon black 0.25 2 Layer ratio*2) [layer (A)/layer (B)] 0.00/1.00 1.00/0.00 0.55/0.45 0.90/0.10 0.80/0.20 0.44/0.36 1.26/0.09 (1) stored at 50 C for 10 0 10 10 10 10 10 30 days # 0 5 0 0 0 0 0 Results x 0 5 0 0 0 0 0 (2) exposed to solar 0 10 10 10 10 10 10 rays # 20 0 0 0 0 0 x 8 0 0 0 0 0 0 *1) low-density polyethylene resin: Sholex 5503D mfd. by Showa Denko K.K.

*2) The average wall thickness of the container as well as the thickness of the layer (A) and that of the layer (B) are expressed in mm.

Claims

CLAIMS:

1. A multi layer container for storing a liquid bleach composition, the container having an outer layer (A) comprising a thermoplastic resin containing a pigment and a pigment-free inner layer (B) comprising a thermoplastic resin.

2. A multilayer container as claimed in Claim 1, wherein the ratio of the thickness of the layer (A) to that of the layer (B) is 99.99 : 0.01 to 50 : 50.

3. A multilayer container as claimed in Claim 1, wherein the ratio of the thickness of the layer (A) to that of the layer (B) is 99 : 1 to 55 : 45.

4. A multilayer container as claimed in Claim 1, wherein the layer (A) comprises 99 to 80% by weight of the thermoplastic resin(s) and 1 to 20% by weight of the pigment(s).

5. A multilayer container as claimed in any one of Claims 1 to 4, wherein the pigment is selected from the group consisting of a pigment of phthalocyanine group, a pigment of azo group, a pigment of metal oxide, carbon black, or a mixture thereof.

6. A multilayer container as claimed in any one of Claims 1 to 5, wherein the thermoplastic resin is selected from a polyolefin and a polystyrene.

7. A multilayer contained as claimed in any one of Claims 1 to 5, wherein the thermoplastic resin is polyethylene.

8. A multilayer container as claimed in Claim 7, wherein the polyethylene is a low-density polyethylene.

9. A multilayer container as claimed in any preceding claim wherein at least one pigment-free layer is provided between layer (A) and (

10. A multilayer container as claimed in Claim 1, wherein the liquid bleach composition is an aqueous hydrogen peroxide solution.

11. A multilayer container for storing a liquid bleach composition substantially as described herein with reference to the accompanying drawing.

12. A liquid bleach disposed in a multilayer container comprising a liquid bleach composition and a thermoformed multilayer container, the thermoformed multilayer container having a outer layer (A) comprising a thermoplastic resin(s) and a pigment(s) and a inner layer (B) comprising a thermoplastic resin(s) and no pigment formed on the inside of the layer (A).

13. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the ratio df the thickness of the layer (A) to that of the layer (B) is 99.99 : 0.01 to 50 : 50.

14. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the ratio of the thickness of the layer (A) to that of the layer (B) is 99 : 1 to 55 : 45.

15. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the layer (A) comprises 99 to 80% by weight of the thermoplastic resin(s) and 1 to 20% by weight of the pigment(s).

16. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the pigment is selected from the group consisting qf a pigment of phthalocyanine group, a pigment of azo group, a pigment of metal oxide, carbon black and a mixture thereof.

17. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the thermoplastic resin is selected from the group consisting of a polyolefin and a polystyrene.

13. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the thermoplastic resin is a polyethylene.

13. The liquid bleach disposed in a multilayer container according to Claim 18, wherein the polyethylene is a low-density polyethylene.

20. The liquid bleach disposed in a multilayer container according to Claim 12, wherein the liquid bleach composition is an aqueous hydrogen peroxide solution.

21. A thermoformed multilayer container for housing a liquid bleach composition having a outer layer (A) comprising a thermoplastic resin(s) and a pigments and a inner layer (B) comprising a thermoplastic resin(s) and no pigment formed on the inside of the layer (A).