JPH04136066A - Packaging material - Google Patents

Abstract

PURPOSE:To provide a packaging material which is excellent in bio- degradability, nonpolluting to the environment and excellent in flexibility, processability, profitability, etc., by mixing a polyhydroxyalkanoate polymer with a specified amount of a lipid compound and molding the mixture. CONSTITUTION:A base comprising a polyhydroxyalkanoate [e.g. poly(3- hydroxybutyrate)] or its copolymer (e.g. 3-hydroxybutyrate/3-hydroxypropionate copolymer) or a mixture thereof is mixed with 0.01-60wt.% lipid compound. Examples of the lipid compounds include glycerol triacetate, glycerol monostearate and monoethyl terephthalate. The obtained resin composition is optionally mixed with a filler, a lubricant, etc., and molded into a packaging material in the form of a film, a bag, a cup or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a packaging material that is not only biodegradable but also has excellent physical properties such as flexibility and processability.

<Conventional technology> Medical products, foodstuffs, various industrial products, etc. are packaged in various packaging materials such as sheets, bags, and boxes to prevent stains and damage, and to improve aesthetics and product value. It is distributed on the market in the same condition.

Traditionally, paper has been widely used as such packaging material, but in recent years, various resin materials, such as soft polyvinyl chloride, have replaced paper in terms of strength, workability, freedom of shape, etc. , low density or high density polyethylene, linear low density polyethylene, polypropylene, polystyrene, ionomers, various resins such as polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyacrylonitrile, polymethyl methacrylate, nylon, polyester, etc. Polymers and mixtures are commonly used as materials.

Packaging materials to which such resins are applied are made by mixing various additives such as plasticizers, softeners, crosslinking agents, etc. with the resin as needed, and are made into films, sheets, plates, boxes, and bottles. or by combining multiple types of molded films using coextrusion or lamination technology, and if necessary, by irradiating ionizing radiation after molding to promote crosslinking, etc. It is used as a packaging material with various physical properties and shapes.

By the way, most packaging materials that are made of resin are disposable, and after being used for their respective purposes, they are disposed of as waste without being collected. However, the aforementioned resins do not naturally decompose and remain in their original form for many years even if they are discarded, causing various social problems such as environmental pollution. This is a well-known fact. There is also a method of incineration, but resin materials such as those mentioned above cannot be incinerated unless they are at high temperatures, and if they generate harmful gases, mainly halides, they must be removed. Since equipment is also required, expensive equipment is required.
Also, running costs are high. Furthermore, the release of carbon dioxide gas generated by incineration is not just environmental pollution, but is also evolving into a major problem of global warming.

In response to these various problems, in recent years traditional paper packaging has been reconsidered, and so-called biodegradable materials, which are polymeric materials that can be decomposed by the natural ecosystem when discarded or left in the natural world, have been widely used. It is being studied and attracting attention.

<Problem to be solved by the invention> However, packaging materials made of paper have limitations in their physical properties, so there are significant limitations in terms of strength, freedom of shape, etc., and it is difficult to obtain the necessary characteristics depending on the packaged item. often cannot. Furthermore, since paper uses wood valves as the main raw material, large consumption is not very desirable from the standpoint of protecting forest resources.

On the other hand, as a biodegradable material, a polymer modification material is known that is made by mixing cornstarch into polypropylene, polyethylene, etc., for the purpose of collapsing the shape, but this only collapses in shape over time. It is hard to say that it is a biodegradable material in the sense of contribution.

Furthermore, poly(3-hydroxybutyrate) or a copolymer containing poly(3-hydroxybutyrate) as a main component is known as a biodegradable material. It has been confirmed that poly(3-hydroxybutyrate) decomposes well when left in the natural environment, and it also has excellent biocompatibility, so it was expected to be used in a variety of fields. . however,
Poly(3-hydroxybutyrate) is hard and brittle, so there are problems with its physical properties such as poor impact resistance, and although it has thermoplasticity, it begins to thermally decompose even below its melting point, making it difficult to process. It has poor properties and is difficult to apply to packaging materials that require various shapes and physical properties depending on the packaged item.

On the other hand, as an attempt to change the physical properties of poly(3-hydroxybutyrate), D-(-)3-hydroxybutyrate and D-
Copolymers containing (-)3-hydroxyvalerate and the like as repeating units are known. Although this copolymer has good effects in terms of lowering the melting point and improving flexibility,
It requires a special substrate and is expensive due to low productivity, which poses problems for general-purpose applications such as packaging materials.

Furthermore, attempts have also been made to modify poly(3-hydroxybutyrate) by mixing it with other resin materials such as ethylene oxide, ethylene propylene rubber, polyvinyl acetate, etc. However, in either method, problems remain in the stability, economic efficiency, processability, etc. of the resin composition obtained, and it is difficult to use it as a packaging material.

The purpose of the present invention is to solve the problems of the prior art, and by using a specified resin composition as a material, it has excellent biodegradability and can be disposed of in a landfill or in the ocean after use. It is an object of the present invention to provide a packaging material that decomposes in a short time when left in the natural environment, does not cause environmental pollution, and has excellent processability, economic efficiency, etc.

<Means for Solving the Problems> In order to achieve the above object, the present invention has a polyhydroxyalkanoate, a copolymer thereof, or a mixture thereof as a main component, and a lipid compound of 0.01 to 6
A packaging material is provided, characterized in that it is molded from a resin composition containing 0% by weight.

Further, the polyhydroxyalkanoate may be poly(3-
Hydroxyalkanoates) are preferred.

Further, the polyhydroxyalkanoate is poly(4-
Hydroxyalkanoates) are preferred.

Further, the polyhydroxyalkanoate may be poly(5-
Hydroxyalkanoates) are preferred.

In addition, any shape such as film, sheet, tube, box, bag, hollow cylinder, cup, concave, bottle, band, string, sphere, or net shape, or two or more of these shapes, may be used. Preferably, it has a composite shape.

Hereinafter, a specific configuration of the present invention will be explained in detail.

The packaging material of the present invention is at least partially formed by a resin composition containing polyhydroxyalkanoate, a copolymer thereof, or a mixture thereof as a main component and containing 0.01 to 60% by weight of a lipid compound. It is formed by forming.

The packaging material of the present invention has good productivity, processability,
It is economical, has excellent biodegradability, is inexpensive, and can be used in the sea.
Since it decomposes well when left in the natural environment such as soil, it does not cause environmental pollution when disposed of.

Here, in the present invention, packaging materials include not only films and sheets, but also those processed into cylinders, bags, boxes, bottles, etc., composites of various shapes, and even a plurality of bottles.
It includes all materials used to wrap or fill at least a portion of a certain item, regardless of whether it is liquid, gas, or any other structure, such as string-like or band-like members used to bundle cans, etc.

The packaging material of the present invention basically has polyhydroxyalkanoate, a copolymer thereof, or a mixture thereof as a main component, and contains 0.01 to 60% by weight of a lipid compound, and has good biodegradability. Examples of commercially available polyhydroxyalkanoates formed from resin compositions having hydroxyalkanoate repeating units include those having about 3 to 12 carbon atoms, and specifically, poly(3
-hydroxypropionate), poly(3-hydroxybutyrate), poly(3-hydroxyalkanoates) such as poly(3-hydroxyvalerate), poly(3-hydroxyoctanoate), poly(4- hydroxybutyrate), poly(4-hydroxyalkanoates) such as poly(4-hydroxyvalerate), poly(5-hydroxyalkanoates) such as
Poly(5-hydroxyalkanoates) such as hydroxyvalerate) are preferably used. In particular,
Poly(3-hydroxybutyrate) is preferably applied.

In the present invention, not only polyhydroxyalkanoate car bodies but also copolymers thereof are suitably applied. As a copolymer of polyhydroxyalkanoate, poly(
Copolymers of 3-hydroxybutyrate) and other hydroxyalkanoates having 3 to 12 carbon atoms are exemplified,
Specifically, (3-hydroxybutyrate) (3-hydroxypropionate) copolymer (3-hydroxybutyrate)-(3-hydroxypropionate)-(
(4-hydroxybutyrate) copolymer (3-hydroxybutyrate) - (3-hydroxyvalerate) copolymer (3-hydroxybutyrate) (3-hydroxyvalerate) - (3-hydroxyhexanoate)
-(3-hydroxyheptanoate) copolymer (3
-hydroxybutyrate)-(3-hydroxyvalyrate)(3-hydroxyhexanoate)-(3-hydroxyheptanoate)-(3-hydroxyoctanoate) copolymer (3-hydroxybutyrate)-(3
-Hydroxyhexanoate)-(3-hydroxyoctanoate) copolymer (3-hydroxybutyrate)(3-hydroxyvalerate)-(3-hydroxyheptanoate)-(3-hydroxyheptanoate)
Copolymer, (3-hydroxybutyrate)-(3-hydroxyvalerate)(3-hydroxyhexanoate)-(3-hydroxyheptanoate)-(3-hydroxyheoctanoate)-(3-hydroxynona/! −
Preferred examples include (3-hydroxyvalerate) (3-hydroxyundecanoate)-(3-hydroxylaurate) copolymer, (3-hydroxybutyrate)-(4-hydroxyvalerate) copolymer, etc. However,
It is not particularly limited to these.

In addition, in the present invention, a mixture of the above-mentioned polyhydroxyalkanoates or a mixture of the above-mentioned copolymers,
Furthermore, a mixture of the two can also be suitably applied.

These polyhydroxyalkanoates and their copolymers are produced by various microorganisms as is well known, but in the present invention, they may be produced by any of them. Alternatively, it may be obtained by chemical synthesis.

Examples of microorganisms that produce polyhydroxyalkanoates include Acinetobacter [Ac1netobacter].
er] Actinomycetus [Actin
omysetesl alcaligenes [Alcal
igenesl Aphanothe [Aphanothe]
cel Aquaspirillum [Aquaspirillum]
ua+] Azospirillum [^xospirill
um], Azotobacter
Bacillus [Bacillus, Begiatoa [B e
gg 1atoa] Beierinckia [Be1je
rinckia], Caulobacter [Caulobac
ter] Chlorofretuce [Chlorofrexe
us] Chlorogloea [(:hlorogl.

eal Chromatium [(1: chromobacterium
ml Clostridium [Clostridium]
Derxial, Ecthothorhodospira, Echerichia, Ferrobacillus, Gamphosphaerial, Haea + Ophilus, Halobacterium Ha
lobacterium hyphomicrobium [
) Iyphomicrobiuml, Lamprocystis, Lamprobedia [
Lampropedial Rebutothrix [L
eptothrixl, Methylobacterium [Meth
ylobacterium ml, Methylocystice [M
ethylocystis] Micrococcus [M
icrococcusl [Micr
oc.

1eus] Microcystis [Microcys
tis] Moraxella [Mycoplana] Nitrobacter [
N1trobacter] Nitrococcus [N1tro
coccus] Nocardia,
Oceanospiri11um
] Paracoccus, Photobacterium, Pseudomonas, Rhizobium, Rhodobacterium
obacter] Rhodospirillum [Rhodosp
iri 11LIG+], Sphae
rotilus], Spirillum [Spirillum]
Spirulina [5pirulina], Streptomyces [Streptomycesl, Syntrophomonas [5yntrophoa+onas], Thiobacillus [Th1obacillus], Thiobacillus [Th
1ocapsa] Thiocystice [Th1ocy
stjs], thiodicty ion [Th1odicty
on] Thiopedia [Th1opedia]
Thiosphaeral [Vibriol], Santobacter [Xanthoba]
Examples include various bacteria belonging to bacterial species such as C. cterl and Zoogloea.

The number average molecular weight Mw of the polyhydroxyalkanoate and its copolymer synthesized by fermentation in this way is usually 1.
It is about 0,000 to 3,000,000.
In addition, after fermentation synthesis, for example, heat treatment or γ
The molecular weight is reduced by post-treatment such as radiation treatment, e.g.
000 to about 000 to ooo can also be suitably used.

The resin composition commonly used in the packaging material of the present invention has such a polyhydroxyalkanoate or a copolymer thereof as a main component, and contains 0.01 to 60% by weight of a lipid compound.

Lipid compounds to be blended include monoglycerides, diglycerides, triglycerides, monocarboxylic acid esters,
Dicarboxylic acid monoester, dicarboxylic acid diester,
Dialcohol monoester, dialcohol diester,
Examples include one or more of tricarboxylic acid monoester, tricarboxylic acid diester, and tricarboxylic acid triester.

Various glycerides include fatty acid glycerin esters having 2 to 18 carbon atoms; specifically, monoglycerides include glycerol monoacetate, glycerol monopropionate, glycerol monobutyrate, glycerol monolaurate, glycerol monomyristate,
Glyceryl monopalmitate, glycerol monostearate, etc.; diglycerides include glycerol diacetate, glycerol dipropionate, glycerol diacetate, glycerol dilaurate, glycerol similystate, glycerol dipalmitate, glycerol distearate, etc.; as triglycerides Glycerol triacetate, glycerol tripropionate, glycerol tributyrate, glycerol trilaurate, glycerol tripalmitate, glycerol trimyristate,
Various suitable examples include glycerol tristearate and the like.

Furthermore, as carboxylic acid esters, carbon atoms of 2 to 3
Examples include esters consisting of 0 carboxylic acid and an alkyl having 2 to 3 carbon atoms. Specifically, saturated or unsaturated monocarboxylic acid esters include 〇-amyl acetate, ethyl propionate, methyl caproate, Examples of saturated or unsaturated dicarboxylic acid monoesters such as ethyl crotonate and n-butyl oleate include monomethyl sebacate, mono-n-butyl maleate, monoethyl terephthalate, and the like: Saturated or unsaturated dicarboxylic acids As a diester,
Dimethyl sebacate, dimethyl terephthalate, di(2-ethylhexyl) phthalate, di-n-octyl phthalate, etc.; tricarboxylic acid monoesters include monomethyl trimellidate, mono-n-butyl trimellidate, etc.; tricarboxylic acid diesters Examples of the tricarboxylic acid triester include trimethyl trimelate, tributyl trimelate, etc.; Examples of the dialcohol monoester include ethylene glycol monostearate, propylene glycol monostearate, etc. ; Preferred examples of the dialcohol diester include ethylene glycol distearate, propylene glycol distearate, and the like.

In addition, these lipid compounds may be liquid or solid at room temperature.

In the resin composition applied to the packaging material of the present invention, these lipid compounds act as a kind of plasticizer or flexibility imparting agent for the polyhydroxyalkanoate. Furthermore, some of it will lower the melting point and glass transition B temperature of the resin. Therefore, the resin composition that can be used in the present invention has significantly improved flexibility at the operating temperature (for example, room temperature) compared to polyhydroxyalkanoate or its copolymer, and some of it has Since the heating temperature can be lowered, unnecessary thermal decomposition and the like can also be prevented.

Moreover, these lipid compounds are generally inexpensive, so they are economically advantageous.

The content of such lipid compounds in the resin composition applied to the packaging material of the present invention is 0.01 to 60% by weight, preferably 1 to 40% by weight. If the content of the lipid compound is less than 0.01% by weight, the effect of improving the physical properties of the polyhydroxyalkanoate will not be sufficiently obtained;
If the content exceeds 0% by weight, the lipid compound will cause layer separation, resulting in a decrease in the physical properties of the resulting packaging material.

The polyhydroxyalkanoate and these lipid compounds can be mixed by dissolving them in an appropriate solvent such as chloroform or dichloromethane, mixing them, and then evaporating the solvent, or by mechanically mixing them using a mixing roll or a Banbury mixer. It is possible to use methods such as mixing the

The biodegradable resin composition used in the packaging material of the present invention is described in detail in Japanese Patent Application No. 2-76585 filed by the present applicant.

In addition, various fillers, dyes, pigments, lubricants, antioxidants, heat stabilizers, etc. may be mixed into such resin compositions as necessary.

The packaging material of the present invention is molded from the above-mentioned biodegradable resin composition (hereinafter referred to as biodegradable material).

As mentioned above, the packaging material in the present invention includes all materials used to wrap at least a portion of a certain item or to fill a certain item. Therefore, there is no limitation on its shape; for example, it may be in the form of a film or sheet that envelops at least a portion of the object to be packaged; Concave shapes such as cylindrical shapes, cup shapes, and bottom shapes with one side closed, and their lids; Bottle shapes, hollow column shapes, and their lids particularly suitable for filling liquids, etc.; Various bottles, cans, etc. Various shapes can be applied depending on the shape and material of the object to be packaged, such as a band shape, a string shape, a thread shape, etc., which are applicable to bundling, etc.; and a composite shape of these.

Furthermore, there are no limitations to the objects to be packaged to which the packaging material of the present invention can be applied, and all objects are covered, regardless of whether they are liquids, gases, or various structures. Specifically, needles, syringes,
Catheters, infusion sets, blood transfusion sets, infusion bags, blood circuits, pharmaceuticals in the form of granules or tablets, testing reagents, artificial organs such as dialysis machines, medical products such as electronic thermometers, electronic blood pressure monitors, and other medical products, fresh or processed. Examples include foods, various beverages, various daily necessities such as clothing and detergents, and various other industrial products.

The biodegradable material applied to the packaging material of the present invention has thermoplasticity. Therefore, as a method for molding the packaging material of the present invention, any resin processing method commonly used for ordinary thermoplastic resins can be applied.

Preferred examples include extrusion molding, particularly extrusion molding using a T-die or inflation; various injection moldings: blow molding, particularly extrusion blow molding or injection blow molding; calendar molding; casting method, powder molding method; etc. Ru. Further, the molding may be performed while heating. Furthermore, the biodegradable material is formed into a sheet by extrusion molding, calendar molding, etc. 1. This sheet may be formed into a structure or a laminate in a desired shape by vacuum forming, press forming, laminated press forming, or dissolving in chloroform and coating.
It may also be a foam.

The packaging material of the present invention is not limited to those that are integrally molded by the above-mentioned various molding methods; for example, two sheets or films obtained by extrusion molding using a T-die are heat-sealed or high-frequency sealed. It can also be processed into a bag body by processing it using methods such as methods, or when molding a bottle, etc., the main body and bottom are molded separately, and then molded integrally by heat sealing, high frequency sealing, or ultrasonic sealing. It may be. In this case, the molding methods for the individual members may be the same or different.

Moreover, it goes without saying that the packaging material of the present invention may be colored, printed, etc. on the surface after being molded.

The packaging material of the present invention molded in this way can be used for medical products,
When it is necessary to disinfect or sterilize the material, such as when it is used as a food packaging material, various known disinfection and sterilization methods can be applied. For example, suitable sterilization methods include autoclave sterilization, ultraviolet sterilization, ionizing radiation sterilization such as gamma rays and electron beams, gas sterilization using ethylene oxide, etc., and preferred disinfection methods include cresol, disinfectant ethanol, etc. .

<Example> Hereinafter, the present invention will be explained in more detail by giving specific examples of the packaging material of the present invention.

[Example 1] Poly(3-hydroxybutyrate) (Mw=870.0
00 (manufactured by Aldrich) and glycerol triacetate (manufactured by Tokyo Kasei ■) were dissolved and mixed in chloroform at a weight ratio of 80:20, and then the chloroform was evaporated to obtain a sheet with a thickness of 2 mm.

Cut the obtained sheet with a cutter to make a pellet,
Using this pellet as a raw material, T-die extrusion molding was performed using a blast mill (manufactured by Toyo Seiki Seisakusho ■) at a nozzle and die temperature of 160° C. to obtain a sheet with a thickness of about 100 μm.

Note that no trouble occurred during molding, and the sheet obtained was highly flexible.

Using the obtained sheet, a bag 1 as shown in FIG.
0 was made by heat sealing, and 50
An infusion bag 12 containing 0 mu of physiological saline (Terumo saline manufactured by Chiru Sen) was placed and sealed with a heat seal.

This bag 10 was wrapped in cardboard and left in the trunk of a car used for commuting for two weeks, but no problems such as tearing of the bag 10 occurred. In addition, the bag maintained its flexibility and was in a state where it could withstand continued use.

Thereafter, the infusion bag 12 was taken out, and only the bag body 10 was buried in the soil in Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture, and when it was dug up at the ridge, it was found to have completely disintegrated and not retained its original shape.

[Example 2 A sheet having a thickness of 2 cm was obtained in the same manner as in Example 1.

Vacuum forming this sheet while heating it to 165℃,
¥S2 A bottom material 14 as shown in the figure was molded.

An injection needle (Terumo ■ 18G injection needle) is attached to this bottom material 14.
was placed in the container, the container was covered with the 100 μm sheet obtained in Example 1, and the two were fused and sealed using heat sealing.

This bottom material 14 was left in the trunk of a car used for commuting for two weeks, but no problems occurred and both were found to be usable as packaging materials.

Afterwards, this bottom material 14 was buried in the soil in Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture with the syringe needle still in it, and when it was dug up six months later, only the syringe needle was found, and the bottom material 14 and the sheet had completely decomposed. It did not retain its original shape.

[Example 3] A sheet with a thickness of 100 μm was produced in the same manner as in Example 1, except that glycerol trilaurate (manufactured by Tokyo Kasei) was used instead of glycerol triacetate, and the nozzle temperature and T-die temperature were 175°C. Obtained.

When an experiment was conducted using this sheet in the same manner as in Example 1, there were no problems in use, and the bag completely disassembled after 6 months and did not retain its original shape.

[Comparative Example 1] A sheet with a thickness of 100 μm was produced in the same manner as in Example 1 except that glycerol triacetate was not used, but the obtained sheet had poor flexibility and could not be used as a packaging material. .

[Comparative Example 2] Polyethylene and polyester having a thickness of 30 μm were co-extruded to obtain a composite sheet having a thickness of 130 μm.

This composite sheet had no problems when used as a packaging material, but when it was buried in the same soil as in the previous example and dug up 6 months later, no particular change in appearance was observed.
It was not biodegradable at all.

[Example 4] After applying a small amount of a solvent-based adhesive (manufactured by Konishi Aji Co., Ltd.) 1303) to the top surface of the bottom material 14 obtained in Example 2, the sheet obtained in Example 1 was covered with a lid while applying pressure. . After being left at room temperature for one week, there were no problems, and the lid could be removed by hand, confirming that the bottom material 14 could be used as a packaging material.

Roughly, the bottom material 14 was buried in the soil in Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture, and when it was dug up six months later, the adhesive part had decomposed to the extent that it could not be seen with the naked eye and had not retained its original shape.

From the above results, the effects of the present invention are clear.

<Effects of the Invention> As explained in detail above, the packaging material of the present invention has excellent biodegradability by using a predetermined resin composition having good biodegradability as a material, and does not require landfilling after use. It can be disposed of in the ocean, in the sea, in activated sludge, etc., and left in the environment to decompose in a short period of time without causing environmental pollution. Furthermore, it has excellent processability and economic efficiency, so it can be used for various purposes. It is suitable for use as a packaging material for goods.

FIG. 2 is a schematic diagram showing an example of the bottom material of the packaging material of the present invention.

Explanation of symbols 10...bag body, 12... Infusion bag, 14...Bottom material patent applicant representative person same Tele

Claims (5)

[Claims] (1) A packaging characterized by being molded from a resin composition containing polyhydroxyalkanoate, a copolymer thereof, or a mixture thereof as a main component and containing 0.01 to 60% by weight of a lipid compound. Material. (2) The polyhydroxyalkanoate is poly(3-
The packaging material according to claim 1, wherein the packaging material is a hydroxyalkanoate. (3) The polyhydroxyalkanoate is poly(4-
The packaging material according to claim 1, wherein the packaging material is a hydroxyalkanoate. (4) The polyhydroxyalkanoate is poly(5-
The packaging material according to claim 1, wherein the packaging material is a hydroxyalkanoate. (5) Film-like, sheet-like, cylindrical, box-like, bag-like, hollow cylinder-like, cup-like, concave-shaped, bottle-like, band-like, string-like, spherical, net-like, or two or more of these shapes. The packaging material according to any one of claims 1 to 4, which has a composite shape.