JPH0370761A - Disintegrating resin composition - Google Patents

Abstract

PURPOSE:To obtain a disintegrating resin composition slowly disintegrating by the action of light, etc., within a specific period, useful from the viewpoint of waste disposal and suitable for food packaging, etc., by compounding a thermoplastic resin and a block copolymer having high vinyl bond content in the conjugated diene block. CONSTITUTION:The objective composition is produced by compounding (A) a block copolymer composed of a conjugated diene (e.g. 1,3-butadiene) and a vinyl aromatic hydrocarbon (e.g. styrene or 0-methylstyrene), containing 5-95wt.% (preferably 15-85wt.%) of the vinyl aromatic hydrocarbon, having a vinyl bond content of >=15wt.% (preferably 20-80wt.%) in the conjugated diene block, containing at least one structure unit containing a polymer block composed of a conjugated diene polymer and/or a copolymer of conjugated diene and a vinyl aromatic hydrocarbon bonded at both terminals to vinyl aromatic hydrocarbon polymer blocks and having a distribution width of the vinyl bond content in the conjugated diene block of >=5% and (B) A thermoplastic resin.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an easily disintegrating resin composition that gradually deteriorates and disintegrates over a specific period of time due to exposure to light, etc. The present invention relates to a resin composition having the above properties and comprising a block copolymer with a high bond content and a thermoplastic resin. The easily disintegrating resin composition of the present invention is particularly useful from the viewpoint of waste disposal.

[Conventional technology]

Block copolymers consisting of conjugated dienes and vinyl aromatic hydrocarbons exhibit elasticity similar to that of vulcanized natural or synthetic rubber without vulcanization when the vinyl aromatic hydrocarbon content is relatively low. It is widely used in the fields of footwear, plastic modification, asphalt, adhesives, etc. because it has the same processability as thermoplastic resins at room temperature and at high temperatures. In addition, when the vinyl aromatic hydrocarbon content is relatively high, a thermoplastic resin that is transparent and has excellent impact resistance can be obtained, so its usage has increased in recent years, mainly in the food packaging container field, and its applications have also expanded. It is becoming more diverse.

In these various uses, block copolymers are generally used in combination with inorganic fillers, organic fillers, thermoplastic resins, and the like. For example, Tokuko Shou 45-19388, Tokuko Sho 5
1-36292, JP-A No. 53-96048 discloses that the block copolymer contains a thermoplastic resin such as polystyrene or polyethylene, a softening agent such as naphthenic oil, clay,
The use of compositions containing organic fillers such as calcium carbonate in footwear has been described. Also special public service 1971-1971
Publication No. 28, Special Publication No. 47-43618, Special Publication No. 5
No. 2-21012 describes a method of improving impact resistance by blending the block copolymer with polystyrene or rubber-modified polystyrene. Similarly, the Special Public Interest Publication in 1977-
19935, Japanese Patent Publication No. 45-4824, Japanese Patent Publication No. 46-5067, Japanese Patent Publication No. 1867-1982, and Japanese Patent Publication No. 82851-1987, respectively, disclose polypropylene, polyethylene, acrylic resin, vinyl chloride resin, Attempts have been made to improve the properties of polyphenylene ether resins by blending them with the above block copolymers.

By the way, synthetic polymer materials such as synthetic resins and synthetic rubbers are generally less susceptible to deterioration due to oxygen, ozone, ultraviolet rays, water, etc. in the natural environment, and are less susceptible to decomposition by microorganisms than natural polymers. Waste causes various social problems such as deterioration of the natural environment and living environment, obstruction of production activities in the agriculture and fisheries industries, and generation of secondary pollution due to incomplete treatment. Therefore, in order to solve these problems, various attempts have been made to impart photodegradability or microbial degradability to synthetic polymer materials, thereby making them easier to decompose in the natural environment.

For example, Japanese Patent Publication No. 49-37591 discloses the production of easily degradable resins that promote autooxidative decomposition by radically copolymerizing a mixture of styrene and butadiene, isoprene, or a mixture of butadiene and isoprene in any proportion. The law is stated. Also, special public service 1977-18
Publication No. 812 describes a copolymer of ethylene and carbon monoxide which is introduced into light to promote photocatalytic oxidative deterioration. Furthermore, Japanese Patent Publication No. 49-1304 and Special Publication No. 51-2
No. 110 describes a resin composition to which a transition metal compound is added as a catalytic oxidative decomposition accelerator, and a resin composition to which a compound such as benzophenone or anthracene is added as a photosensitized oxidative decomposition accelerator.

On the other hand, attempts have been made to improve the photodegradability of block copolymers composed of conjugated dienes and vinyl aromatic hydrocarbons. ~90vt% block copolymer resin with a styrenic hydrocarbon content of 10~
A photodegradable film or tape containing 40 wt% block copolymer rubber is described. However, this photodegradable film or tape is
It is substantially in the same category as the "biaxially oriented heat-shrinkable styrenic film with excellent low-temperature shrinkability and cold impact resistance" described in Publication No. 855, and its photodegradability is insufficient. Improvements are requested.

[Problem to be solved by the invention]

As mentioned above, various methods have been proposed to obtain materials that are easily disintegrated. No attempt has been made to improve it. The present invention has good mechanical strength before being exposed to sunlight or other light, but after being exposed to sunlight or ultraviolet rays for a certain period of time, it easily deteriorates and naturally deteriorates. An object of the present invention is to provide a resin composition that has the property of collapsing.

[Means and effects for solving the problem] The present inventors,
As a result of intensive studies on improving the disintegration properties, particularly the photodisintegration properties, of compositions of thermoplastic resins and block copolymers consisting of conjugated dienes and vinyl aromatic hydrocarbons, it was found that the content of vinyl bonds based on conjugated dienes was The inventors have discovered that the objective can be achieved by using a specific amount of block copolymer, and have completed the present invention.

That is, the present invention comprises (a) a conjugated diene and a vinyl aromatic hydrocarbon, the content of the vinyl aromatic hydrocarbon being 5 to 95% by weight;
The present invention also relates to a collapsible resin composition comprising (b) a thermoplastic resin and a block copolymer having a vinyl bond content of 15% or more in the conjugated diene moiety.

The present invention will be explained in detail below.

In the present invention, the block copolymer used as component (a) consists of a conjugated diene and a vinyl aromatic hydrocarbon, and the content of the vinyl aromatic hydrocarbon is 5 to 95% by weight, preferably 10 to 90% by weight. , more preferably 15-85
% by weight, and the vinyl bond content of the conjugated diene moiety is 15% or more, preferably 15 to 85%, more preferably 20 to 80%. If the vinyl bond content of the conjugated diene moiety is less than 15%, it is not preferred because the disintegrability is insufficient. Vinyl bond content is 85
If it exceeds 85%, not only will the disintegrability become excessive but also the low-temperature properties will tend to be poor, so it is recommended that it be 85% or less. A particularly preferred range of the vinyl bond content of the conjugated diene moiety is 25 to 75%. If the vinyl aromatic hydrocarbon content of the block copolymer used in the present invention is 5% by weight without swirling, it will have poor compatibility with the thermoplastic resin, and if it exceeds 95% by weight, the impact resistance of the composition will deteriorate. It is not desirable because it is insufficient.

The block copolymer used in the present invention is a polymer block consisting of a conjugated diene polymer whose conjugated diene moiety has a vinyl bond content of 15% or more and/or a copolymer of a conjugated diene and a vinyl aromatic hydrocarbon. A block copolymer having at least one structural unit in which both ends of B are bonded to the vinyl aromatic hydrocarbon polymer block A is preferred. A composition using a block copolymer having such a structural unit is a block copolymer having no such structural unit, such as a block copolymer in which only one end of polymer block B is bonded to polymer block A. Superior disintegration properties compared to coalescing. The vinyl aromatic hydrocarbon copolymerized in the polymer block B may be distributed uniformly or in a tapered manner. A plurality of uniformly distributed portions and/or tapered distributed portions may coexist in polymer block B.

The block copolymer used in the present invention has, in its polymer chain, at least one structural unit in which both ends of a polymer block B are bonded to a polymer block A.
As another polymer block, a polymer block B' consisting of a conjugated diene polymer whose conjugated diene moiety has a vinyl bond content of less than 15% and/or a copolymer of a conjugated diene and a vinyl aromatic hydrocarbon is coexisting. be able to. In order to obtain a composition with good disintegrability, the polymer block B' should have one end of its polymer chain bonded to the polymer block A and the other end not bonded to the polymer block A. It is preferable.

In the present invention, the vinyl bond content of the conjugated diene moiety refers to the vinyl bond content of the conjugated diene incorporated in the block copolymer in the bonding modes of 1,2-bonds, 3.4-bonds, and 1,4-bonds. Of these, the proportion is incorporated in the 1,2-bond and 3,4-bond binding modes.

The vinyl bond content can be determined using an infrared spectrophotometer, a nuclear magnetic resonance apparatus, or the like. Furthermore, the vinyl aromatic hydrocarbon in the block copolymer can be measured using an infrared spectrophotometer, an ultraviolet spectrophotometer, a nuclear magnetic resonance apparatus, a refractometer, or the like.

The conjugated diene used in the present invention is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2
, 3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,8-hexadiene, and particularly common ones include 1,3-butadiene and isoprene. These may be used not only alone, but also as a mixture of two or more.

The vinyl aromatic compounds used in the present invention include styrene,
0-methylstyrene, p-methylstyrene, p-te
rt-butylstyrene, 1,3-dimethylstyrene, α
- Methylstyrene, vinylnaphthalene, vinylanthracene, etc., among which styrene is particularly common. These may be used not only alone, but also as a mixture of two or more.

As a method for producing the block copolymer used in the present invention, any conventionally known method can be used as long as the vinyl bond content and block structure are within the range specified by the present invention. As a method for producing the block copolymer used in the present invention, methods that can be applied in principle include, for example,
-19286 Publication, Special Publication No. 17979/1979,
Special Publication No. 45-31951, Special Publication No. 4B-324
Publication No. 15, Special Publication No. 48-2423, Special Publication No. 1977
-4108 Publication, Japanese Patent Publication No. 49-38957, Japanese Patent Publication No. 51-49567, Japanese Patent Publication No. 56-28925
Examples include the method described in No. 1, etc.

These are methods in which a conjugated diene and a vinyl aromatic compound are block copolymerized using a polymerization initiator such as an organolithium compound in a hydrocarbon solvent.

The amount of vinyl bond can be adjusted by using a polar compound as a vinylizing agent in a polymerization method using an organolithium compound as an initiator in a hydrocarbon solvent, and controlling the type, amount used, polymerization temperature, etc. of the polar compound. I can do it.

Hydrocarbon solvents include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane, alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane, or benzene, Aromatic hydrocarbons such as toluene, ethylbenzene, xylene, etc. can be used. Examples of the organic lithium catalyst include organic monolithium compounds, organic dilithium compounds, and organic polylithium compounds. Specific examples of these include, t
ert-butyllithium, hexamethylene dilithium,
Examples include butadienyl dilithium, isoprenyl dilithium, and the like. In addition, as polar compounds, ethers such as tetrahydrofuran, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether, amines such as triethylamine and tetramethylethylenediamine, thioethers, phosphines, phosphoramides, alkylbenzene sulfonates, potassium and sodium alkoxides, etc. can be mentioned.

As the block copolymer before hydrogenation used in the present invention, a block copolymer in which a polar group-containing atomic group is bonded to at least one polymer chain terminal of the block copolymer can be used. Here, the polar group-containing atomic group refers to an atomic group containing at least one atom selected from nitrogen, oxygen, silicon, phosphorus, sulfur, and tin. Specifically, carboxyl group, carbonyl group, thiocarbonyl group, acid halide group, acid anhydride group, carboxylic acid group, thiocarboxylic acid group, aldehyde group, thioaldehyde group, carboxylic acid ester group, amide group, sulfonic acid group. group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, amino group, imino group, nitrile group, pyridyl group, quinoline group, epoxy group, thioepoxy group, sulfide group, isocyanate group, isothioneanate group, halogenated Examples include atomic groups containing at least one polar group selected from a silicon group, an alkoxysilicon group, a tin halide group, an alkyltin group, a phenyltin group, and the like. More specifically, Japanese Patent Application No. 1986-129
Among the terminal-modified block copolymers described in No. 179, terminal-modified block copolymers whose vinyl bond amount and polymer structure are within the scope of the present invention can be used.

A preferred polymer structure of the block copolymer used in the present invention is - formula % formula % ) (In the above formula, A is the polymer block A described above.

B1 is the aforementioned polymer block B5 B2 and B3 are the aforementioned polymer block B or polymer block B'.

However, if at least one of B1 is polymer block B, the others can be polymer block B' as required. X represents a residue of an initiator such as a polyfunctional organolithium compound or a residue of a coupling agent such as silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, polyhalogenated hydrocarbon, carboxylic acid ester, polyvinyl compound, etc. . m and n are integers of 1 or more, generally 1-10, preferably 1-5. ). The block copolymer used in the present invention is
Any mixture of block copolymers represented by the above general formula may be used. Further, if necessary, the block copolymer represented by the above general formula may be mixed with a block copolymer having the general formula AB□ or AB2.

In the block copolymer used in the present invention, the polymer block A and the polymer block B or B' each have a number average molecular weight of s, ooo to 300.000, preferably 5
．． 000 to 200,000, more preferably 7, Ω
00 to ioo, ooo, and the number average molecular weight of the block copolymer as a whole is 10.000 to 1,000.00.
0, preferably 20,000 to 800,000, more preferably go, ooo to 500,000.

The block copolymer used in the present invention has a vinyl aromatic compound content of less than 60% by weight, preferably 55% by weight.
In the following cases, it exhibits properties as a thermoplastic elastomer, and in cases where the content of the vinyl aromatic compound is 60% by weight or more, preferably 65% by weight or more, it exhibits properties as a thermoplastic resin. Therefore, when using a block copolymer having properties as a thermoplastic elastomer, the vinyl aromatic hydrocarbon content should be in the range of 5% by weight or more and less than 60% by weight, preferably 10 to 55% by weight. It is preferable to adjust to Further, when using a block copolymer having properties as a thermoplastic resin, the content of vinyl aromatic hydrocarbon is adjusted to a range of 60 to 95% by weight, preferably 65 to 90% by weight. preferable.

In the present invention, a particularly preferred block copolymer has a vinyl bond content distribution width of 5 in polymer block B.
% or more, preferably 10% or more, more preferably 15%
The above block copolymer is used. By giving the above-mentioned distribution width to the vinyl bond content in the polymer block B, a composition having good disintegration properties and good low-temperature properties can be obtained. In order to have a distribution width in the vinyl bond content, when polymerizing the polymer block B, the polymerization temperature should be 10°C or more and 120°C or less, preferably 15°C or more and 100°C or less, more preferably 20°C or more and 80°C or more. ℃
The following method of varying the polymerization temperature is recommended, but it can also be controlled by adding the above-mentioned polar compounds continuously or sequentially. When varying the vinyl bond content by changing the polymerization temperature, it is undesirable if the variation in the polymerization temperature is less than 10°C because the distribution width is narrow, and if it exceeds 120°C, the vinyl bond content may be lost during polymerization. This is not preferable because the number of active reactions occurring is excessive.

The distribution width of the vinyl bond content in the polymer block B can be determined by, for example, sampling a part of the polymer solution during polymerization of the polymer block B, and calculating the conversion rate of the conjugated diene and the vinyl bond content at that point. It can be determined by comparing the differential vinyl bond contents calculated by the following formula with each other.

(In the above formula, C and C are each sun n
n+1 pull Nan and No, n+1 conversion of conjugated diene, ■ and Vn and 1 are samples Hiro n and n, respectively.
+1 vinyl bond content. The differential vinyl bond content determined from the above formula indicates the vinyl bond content between the polymer chains between conversion C and conversion cn+1. ) When the vinyl bond content in polymer block B has a distribution width, the vinyl bond content of the block is
This is the average value in that block.

In the present invention, the thermoplastic resin used as component (b) is a block conjugate of a vinyl aromatic hydrocarbon with a vinyl aromatic hydrocarbon content of 60 to 95% by weight, which is outside the range specified in the present invention, and a conjugated diene. a polymer resin, a polymer or copolymer of the above vinyl aromatic hydrocarbon monomer, the above vinyl aromatic hydrocarbon monomer and another vinyl monomer,
For example, ethylene, propylene, butylene, vinyl chloride,
At least one selected from vinylidene chloride, vinyl acetate, acrylic esters such as methyl acrylate, methacrylic esters such as methyl methacrylate, copolymers with acrylonitrile, methacrylonitrile, etc., rubber-modified styrenic resins (HIPS), etc. Vinyl aromatic hydrocarbon resins, polyethylene, copolymers of ethylene containing 50% or more of ethylene and other monomers copolymerizable with it, such as ethylene-propylene copolymers, ethylene-vinyl acetate copolymers Coalescence and its hydrolyzate, polyethylene resins such as ethylene-acrylic acid ionomer and chlorinated polyethylene, polypropylene, copolymers of propylene containing 50% or more of propylene and monomers copolymerizable with it, such as propylene-ethylene Copolymers, polypropylene resins such as propylene-ethyl acrylate copolymers and chlorinated polypropylene, polybutene-1, polybutene-based resins that are copolymers of butene-1 and other monomers copolymerizable with it; 50% of polyvinyl chloride, polyvinylidene chloride, vinyl chloride and/or vinylidene chloride
Polyvinyl chloride resin which is a copolymer of vinyl chloride and/or vinylidene chloride containing 50% or more of vinyl chloride and other monomers copolymerizable with it, vinyl acetate containing 50% or more of vinyl acetate and other Polyvinyl acetate resins that are copolymers with copolymerizable monomers and their hydrolysates, acrylic acid and its esters and amides, methacrylic acid and its esters and amides, and 50% or more of these acrylic acid monomers. A polyacrylate resin that is a copolymer with other copolymerizable monomers, a polymer of acrylonitrile and/or methacrylonitrile, and other copolymerizable monomers containing 50% or more of these acrylonitrile monomers. Nitrile resins, which are copolymers of
Polyamide resins such as condensation polymers of aminoundecanoic acid, condensation polymers of hexamethylene diamine and dibasic acids such as adipic acid and sebacic acid, and linear polymers in which the constituent units of the polymer are bonded by repeated ester bonds. Polymers, such as dibasic acids such as phthalic acid and isophthalic acid, or derivatives thereof, and ethylene glycol, propylene glycol,
Polyester resins that are condensates with glycol components such as butylene glycol, polyphenylene ether resins, and polyphenylene ether resins such as grafted polyphenylene ether resins that are obtained by graft polymerizing vinyl-substituted aromatic hydrocarbons to these resins; polyphenylene sulfide resins , polyacetal resins such as polyoxymethylene, copolymers of trioxane and alkylene oxide,
Linear polymers in which the constituent units of the polymer are linked by repeating carbonate-type bonds, e.g. 4.4'-
Polycarbonate resins, polyethers such as polymers obtained by reaction of dihydroxy compounds such as dihydroxydiphenylalkanes and 4,4'-dihydroxydiphenyl sulfide with phosgene, or polymers obtained by transesterification of the dihydroxy compounds and diphenyl carbonate. Polysulfone resins such as sulfone and polyallylsulfone, thermoplastic polyurethane resins obtained by polyaddition reaction of diisocyanate components and glycol components, transpolybutadiene, 1.2-
Polybutadiene resins such as polybutadiene, polyketone resins, polyarylate resins which are polycondensation polymers consisting of bisphenol A and phthalic acid components, structures in which part or all of the hydrogen in chain hydrocarbon polymer compounds is replaced with fluorine. These include fluororesins, polyoxybenzoyl-based resins, and polyimide-based resins. Particularly suitable thermoplastic resins are selected from vinyl aromatic hydrocarbon resins, polyethylene resins, polypropylene resins, polybutene resins, polyvinyl acetate resins and their hydrolysates, polyphenylene ether resins, and polybutadiene resins. At least one type of resin.

In the composition of the present invention, the blending weight ratio of component (a) and component (b) is 99 to 99:1, preferably 3:97 to 9.
The ratio is 7:3, more preferably 5:95-95-5. If the amount of component (a) is less than 1% by weight, there is no improvement effect on the disintegration properties of the composition, and conversely, if the amount of component (b) is less than 1% by weight, component (a) No modification effect was observed.

An inorganic filler and/or an organic filler may be added to the composition of the present invention. Specific examples include calcium carbonate, clay, silica, zinc oxide, magnesium carbonate, magnesium silicate, talc, diatomaceous earth,
Dolomite, mica powder, aluminum sulfate, barium sulfate, graphite, glass fiber, carbon black, high styrene resin, coumaron, indene resin, phenol◆
Formaldehyde resin, modified melamine resin, petroleum resin,
Examples include lignin, wood flour, and carbon fiber. These amounts are 1 to 2 parts per 100 parts by weight of the total amount of component (a) and component (b).
00 parts by weight, preferably 10 to 150 parts by weight.

In addition, a softener can be added to the composition of the present invention,
Specific examples include lubricating oils, paraffinic process oils, naphthenic process oils, aromatic process oils, paraffin, vaseline, asphalt, vegetable oils (castor oil, cottonseed oil, rapeseed oil, soybean oil, etc.), sub-oils,
Examples include rosin, fatty acids, etc., which are not more than 200 parts by weight per 100 parts by weight of the total amount of component (a) and component (b),
Generally 20 to 100 parts by weight, preferably 40 to 80 parts by weight are used.

Furthermore, the composition of the present invention contains crosslinking agents such as organic peroxides and inorganic peroxides, pigments such as titanium white, carbon black, and iron oxide, flame retardants, antioxidants, ultraviolet absorbers, antiblocking agents, and antistatic agents. Examples include agents, lubricants, plasticizers, other fillers, and mixtures thereof. Specifically, "Practical Handbook of Additives for Plastics and Rubber"
(Kagaku Kogyo Co., Ltd.) can be used.

In particular, for the purpose of controlling the disintegration time of the disintegrating composition of the present invention, an ultraviolet absorber and/or a weathering agent may be added to delay disintegration, or a photodisintegration accelerator may be added to accelerate disintegration. is effective.

Examples of the ultraviolet absorber and/or weathering agent include hindered amine compounds such as piperidine derivatives, benzophenone compounds, benzotriazole compounds, and the like. Examples of the photodegradable accelerator include compounds having a carbonyl group such as acetophenone and its derivatives, benzophenone and its derivatives, anthraquinone and its derivatives, and transition metal compounds such as iron, cobalt, nickel, copper, and manganese.

The composition of the present invention is molded into a molded article by various methods. Specific examples of molding methods include compression molding, injection molding, extrusion molding, blow molding (extrusion blow method, injection blow method, injection/extrusion blow moldability, sheet blow method, cold parison method, etc.), calender processing, and laminated molding. , vacuum forming, pressure forming, foaming processing, paste processing, powder processing,
Examples include casting, lining processing, film processing (non-stretched film processing, stretched film processing, lamination, coating processing, etc.). The composition of the present invention can be processed into molded products such as sheets, films, foams, injection molded products of various shapes, blow molded products, pressure molded products, vacuum molded products, laminates, and powders by these molding methods. Ru.

The composition of the present invention can be used for various purposes, but particularly suitable uses include food packaging/containers, medical packaging/containers, etc.
Examples include agricultural materials such as containers, cushioning materials and backing materials for mitigating shock during transportation, backing cases, mulch films for plants, and industrial materials such as civil engineering and construction materials. In addition, when the composition of the present invention is a film, tape or tube, the thickness thereof is generally 10 to 200 μm.
Preferably it is 30 to 100 μm, and in the case of a sheet,
Its thickness is generally between 200 μm and 5 μm, preferably 250 μm.
μm to 311 m.

〔Effect of the invention〕

The disintegrating resin composition of the present invention has good mechanical strength, such as tensile strength, impact resistance, and elongation, before being exposed to light such as sunlight after producing a molded article from the composition. However, after being exposed to light such as sunlight or ultraviolet rays for a certain period of time, it easily deteriorates and naturally disintegrates.

Therefore, when the disintegrating resin composition of the present invention is used for disposable purposes, unlike conventional synthetic rubber and synthetic resin products, it does not harm the natural environment and does not require the labor of collection, incineration, etc. Therefore, it can be said that it is a particularly useful resin composition from the viewpoint of waste treatment.

〔Example〕

Examples are shown below, but these are representative of the present invention and are not intended to limit the scope of the present invention.

The method for producing the block copolymer used in the examples of the present invention is illustrated below.

[Block copolymer (A)] Under a nitrogen gas atmosphere, 0.09 parts by weight of n-butyllithium and 0.05 parts by weight of tetramethylethylenediamine as a polar compound were added to a cyclohexane solution containing 10 parts by weight of styrene, After polymerizing at 50°C for 1 hour,
A cyclohexane solution containing 80 parts by weight of butadiene was added and polymerized for 2 hours. In this polymerization of butadiene, the temperature at the initial stage of the polymerization was set at 50°C, and the polymerization temperature was gradually raised to 80°C at the end of the polymerization. Thereafter, a cyclohexane solution containing 10 parts by weight of styrene was added, and polymerization was carried out at a temperature of about 75° C. for 30 minutes. The obtained block copolymer has an A-B-A structure, a styrene content of 20% by weight, and an average vinyl bond content of the butadiene moiety in polymer block B of 40%. Met. Further, the distribution width of the vinyl bond content in polymer block B was measured using the method described in the present invention, and was found to be about 18%.

[Block copolymer (B)] In a nitrogen gas atmosphere, 0.11 parts by weight of n-butyllithium was added to a cyclohexane solution containing 10 parts by weight of butadiene and 3 parts by weight of styrene, and after polymerization at 60°C for 1 hour. , A cyclohexane solution containing 15 parts by weight of styrene was added, and the mixture was further polymerized at 60° C. for 1 hour. Next, a cyclohexane solution containing 0.08 parts by weight of tetramethylethylenediamine as a polar compound, 50 parts by weight of butadiene, and 7 parts by weight of styrene was added and polymerized for 2 hours. still,
At this time, the temperature at the beginning of the polymerization was set at 60°C, and the polymerization temperature was gradually raised to adjust the polymerization temperature to about 80°C at the end of the polymerization. Thereafter, a cyclohexane solution containing 15 parts by weight of styrene was added and
Polymerization was carried out for 0 minutes. The obtained block copolymer is B'-
Has an A-B-A structure and contains 140% by weight of styrene.
The average value of the vinyl bond content of the butadiene moiety in polymer block B' was 10%, and the average value of the vinyl bond content of the butadiene moiety in polymer block B was 40%. Further, the distribution width of the vinyl bond content in polymer block B was about 13%.

[Block copolymer (C)] Under a nitrogen gas atmosphere, 0.08 parts by weight of n-butyllithium and 0.09 parts by weight of tetramethylethylenediamine were added to a cyclohexane solution containing 35 parts by weight of styrene, and the mixture was heated at 60°C for 1 After polymerizing for an hour, butadiene 20
A cyclohexane solution containing 10 parts by weight of styrene and 10 parts by weight was added and polymerized for 1 hour. In this polymerization of butadiene, the temperature at the initial stage of the polymerization was set at 60°C, and the polymerization temperature was gradually raised to 80°C at the end of the polymerization. Then, a cyclohexane solution containing 35 parts by weight of styrene was added and
Polymerized for hours. The obtained block copolymer is AB-
It had A structure, the styrene content was 80% by weight, the average value of the vinyl bond content in polymer block B was 55%, and the distribution width of the vinyl bond content was about 12%.

[Block copolymer (D)] Under a nitrogen gas atmosphere, 0.17 parts by weight of n-butyllithium and 0.45 parts by weight of tetramethylethylenediamine as a polar compound were added to a cyclohexane solution containing 70 parts by weight of styrene, After polymerizing at 60°C for 1 hour,
A cyclohexane solution containing 30 parts by weight of butadiene was added to the polymerization solution at 60°C, and polymerization was carried out adiabatically. The temperature of the polymerization solution reached a maximum of 90°C.

Thereafter, 0.11 parts by weight of silica tetrachloride was added to carry out a coupling reaction. The main component of the obtained block copolymer has an (A-B-)-481 structure, the styrene content is 75% by weight, the average vinyl bond content in polymer block B is 48%, and the vinyl bond content is 75% by weight. The distribution width of the amount is about 1
It was 1%.

The above block copolymer contains 2,6-di-tert-butyl-4-methylphenol and tris(
0.5 parts by weight of (nonylphenyl) phosphite was added.

Examples 1 to 3 and Comparative Example 1 25 parts by weight of the block copolymer shown in Table 1, 25 parts by weight of ethylene-vinyl acetate copolymer (Evaflex 2505, manufactured by Mitsui Polychemicals), polyethylene (Santic F180S, A composition consisting of 50 parts by weight (manufactured by Asahi Kabo Co., Ltd.) was formed into a bottom film to obtain a film with a thickness of about 50 μm. These films were exposed to the natural environment outdoors for 30 days, and the state of disintegration was examined.

The results are shown in Table 1, and the films made of the compositions of the present invention exhibit good disintegration properties.

(Left below) (Note 1) A block copolymer having a vinyl bond content in the butadiene moiety of polymer block B having the value shown in Table 1 was used as a block copolymer (with the exception of changing the amount of polar compound added). Manufactured by the same method as A). Furthermore, comparative example 1
The block copolymers were prepared without using polar compounds.

(Note 2) Disintegration is evaluated according to the following evaluation ranks.

◎: The film lacks strength and elongation and collapses easily.

○: The film is hardened, and although it has strength, it does not stretch, so it collapses when force is applied.

Δ: Partially disintegrated when force is applied, but the whole does not exhibit uniform disintegration.

×: No significant decrease was observed in the tensile strength and elongation before the collapsibility test, and overall it was difficult to disintegrate.

Examples 4 to 7 and Comparative Example 2 Films similar to those in Example 1 were prepared from the compositions shown in Table 2, and their photodegradability was examined. Second result
Shown in the table.

(Left below) Examples 8, 9 and Comparative Example 3 Polypropylene (Asahi Polypro M1300. Asahi Kasei f
JJ) 70 parts by weight and block copolymer 3 shown in Table 3
A composition consisting of 0 parts by weight is injection molded to produce a sheet having a thickness of 1 inch. The disintegrability of the obtained sheet is examined in the same manner as in Example 1. The disintegration evaluation rank is Example 1
According to the method of

(Left below) Example IO and Comparative Example 4 A composition consisting of 60 parts by weight of the block copolymer shown in Table 4 and 40 parts by weight of polystyrene (Stylon 683, manufactured by Asahi Kabo) was extruded to a thickness of 0. , 3 mm sheets are prepared. The disintegrability of the obtained sheet was examined and the results were reported in the fourth
Shown in the table.

(Left below) (Note 5) Produced in the same manner as block copolymer (C) except that no polar compound was used.

(Note 6) Measure the tensile elongation before and after irradiation for 100 hours with a sunshine weatherometer, and use the tensile elongation retention rate after irradiation as a measure of disintegration.

Evaluation rank of disintegration ◎; Tensile elongation retention less than 20% ○; Tensile elongation retention 20% or more, less than 40% Δ; Tensile elongation retention 40% or more, less than 60% ×; Tensile elongation retention 6
0% or more Example 11 A composition consisting of 15 parts by weight of block copolymer (D) and 85 parts by weight of polystyrene (Stylon 683, manufactured by Chloro Kasei) is biaxially stretched to produce a sheet with a thickness of 0.5+u+. . A tray is formed from this sheet by air pressure forming, and its disintegration upon exposure to outdoor natural environments is examined. This tray exhibits excellent disintegration properties.

Example 12.13 100 parts by weight of the block copolymer shown in Table 5, PS (
Styron 679. Asahi Kaoru) 25 parts by weight, clay 55
A composition consisting of 50 parts by weight of naphthenic oil and 10 parts by weight of titanium oxide is compression molded to produce a sheet with a thickness of 2 mm.

The sheet was exposed to an outdoor natural environment for three months to reduce its disintegration. The results are shown in Table 5.

The evaluation rank of disintegration follows the method of Example 1.

(Left below) Example 14 and Comparative Example 5 A composition is prepared according to the formulation method shown in Table 6, and a film with a thickness of 100 μm is formed by an inflation film forming method. The disintegrability of the obtained film was examined using a sunshine weatherometer, and the results are shown in Table 6. The disintegration evaluation rank is the same as in Example 10.

(Margins below) Example 15 Polyphenylene ether resin ([η) = 0.57) 4
0 parts by weight, 20 parts by weight of polystyrene (Styron 683 manufactured by Asahi Kakai Co., Ltd.), and 40 parts by weight of block copolymer (D) were injection molded to prepare a container with a thickness of 3 mm. The injection molded container is exposed to the natural environment outdoors.

This container exhibits good disintegration properties.

Example 16 A composition consisting of 85 parts by weight of polybutene-1 (manufactured by Mitsui Petrochemical) and 15 parts by weight of the same block copolymer as used in Example 12 was formed into a film with a thickness of 60 μm. . This film is exposed to outdoor natural environment. This film shows good disintegration properties.

Example 17 A block copolymer was prepared in the same manner as for block copolymer (A) except that isoprene was used instead of butadiene, and the same composition as in Example 1 was prepared using the block copolymer. Create. A film with a thickness of about 100 μm is formed from the composition and exposed to an outdoor natural environment. This film shows good disintegration properties.

Example 18 A block copolymer was produced in the same manner as for block copolymer (C) except that paramethylstyrene was used instead of styrene, and the same composition as in Example 10 was prepared using the block copolymer. Create something.

A sheet with a thickness of 0.3 a + m is extruded from the composition,
Exposure to outdoor natural environment. This sheet shows good disintegration properties.

Claims (1)

[Claims] 1. (a) consisting of a conjugated diene and a vinyl aromatic hydrocarbon, the content of the vinyl aromatic hydrocarbon being 5 to 95% by weight,
A collapsible resin composition comprising (b) a thermoplastic resin and a block copolymer having a vinyl bond content of 15% or more in the conjugated diene moiety. 2. A polymer in which the block copolymer of component (a) is a conjugated diene polymer in which the vinyl bond content of the conjugated diene moiety is 15% or more and/or a copolymer of a conjugated diene and a vinyl aromatic hydrocarbon. The collapsible resin composition according to claim 1, which is a block copolymer having at least one structural unit in which both ends of block B are bonded to vinyl aromatic hydrocarbon polymer block A. 3. The collapsible resin composition according to claim 1 or 2, wherein the block copolymer of component (a) has a distribution width of vinyl bond content in the conjugated diene moiety of 5% or more.