JPH11255871A - Lactone-containing resin, lactone-containing resin composition, molded articles thereof, and film - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] A resin excellent in decomposability, moldability and mechanical properties,
To provide a resin composition, a molded product thereof, and a film. SOLUTION: This is a film obtained by molding a resin composition obtained by blending a resin additive into a lactone-containing resin composed of polycaprolactone and another biodegradable resin by an inflation method, wherein the composition of the lactone-containing resin is The component, polycaprolactone, has been irradiated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lactone resin comprising a specific radiation-treated lactone resin alone or a lactone resin comprising the lactone resin and another biodegradable resin, and comprising the lactone resin and a resin additive. A lactone-containing resin composition, a molded product obtained by molding the lactone-containing resin or the lactone-containing resin composition, and a film,
It has excellent decomposability, moldability and mechanical properties.

[0002]

2. Description of the Related Art Conventionally, synthetic plastics such as polyolefin, polyvinyl chloride, polystyrene, polyamide, and polyester have been used as household goods, agricultural, marine, and general industrial materials. Because it is stable and hardly decomposes after being used and disposed of in the natural world, its disposal has become a social problem. As a countermeasure for this, various biodegradable resins have been proposed, and alternatives to the above resins have been studied. Specific examples of the biodegradable resin include aliphatic polyesters such as poly-ε-caprolactone, polyhydroxybutyrate / polyhydroxyvalerate copolymer, and polylactic acid, and modified starch / modified polyvinyl alcohol (PVA) composition. And carbonyl group-containing photodegradable polymers. Of these,
Aliphatic polyesters such as poly-ε-caprolactone, polyhydroxybutyrate / polyhydroxyvalerate copolymer, and polylactic acid have received the most attention because they are completely biodegradable.

JP-A-8-188706 discloses a biodegradable resin, poly-ε-caprolactone (hereinafter sometimes abbreviated as polycaprolactone, PCL).
100% by weight of a mixture of 100% by weight and 20 to 0% by weight of a biodegradable linear polyester resin produced by living organisms
A biodegradable plastic film obtained by molding a composition comprising 0.3 to 0.8 parts by weight of a lubricant with respect to parts by weight is disclosed, but there is a problem in mechanical strength during film formation. Not only is it difficult to mass-produce the film, but also when the film is put into a composting device together with garbage, it takes 100 days for the biochemical decomposition of the film, so the decomposition rate can be said to be sufficiently fast. Absent.

[0004] Also, JP-A-8-11206 discloses that
Proposals have been made to use downward dies for inflation film formation of biodegradable resin, but there is no solution to the problem based on the characteristics of the biodegradable resin itself, only by lowering the extrusion direction. Therefore, it has not been a fundamental solution to the problem in inflation film formation of a biodegradable resin. Japanese Patent Application Laid-Open No. 8-150658 discloses heat sealability, mechanical strength, and the like using a composition comprising a biodegradable aliphatic polyester and a saponified ethylene-vinyl acetate copolymer, starch and a plasticizer. Although a method of forming an inflation film having excellent moisture resistance and the like is disclosed, since a biodegradable ethylene-vinyl acetate copolymer saponified compound is present, some of the biodegradable properties are sacrificed. This is not a disclosure of a solution to the above problem.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a resin, a resin composition and a resin composition having excellent decomposability, moldability, and mechanical properties using a lactone resin. It is intended to provide objects and films.

[0006]

Means for Solving the Problems As a result of extensive studies, the present inventors have found that a lactone resin such as poly-ε-caprolactone or a composition containing the lactone resin is irradiated with a specific radiation to obtain a lactone resin. By forming a crosslinked structure in the molded article, it is found that molded articles using the irradiated lactone resin or the composition thereof, films and the like are excellent in decomposability, moldability, and mechanical properties, thereby completing the present invention. Reached.

That is, one aspect of the present invention is a lactone-containing resin (c) comprising a lactone resin (a) alone or a lactone resin (a) and another biodegradable resin (b),
Component of the lactone-containing resin (c) The lactone-containing resin is characterized in that the lactone resin is subjected to radiation irradiation treatment alone or together with at least one other component. In the second aspect of the present invention, the lactone resin (a) comprises ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone,
3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, a homopolymer of enantholactone, a copolymer of two or more of these monomers, a mixture of these homopolymers or copolymers The lactone-containing resin according to 1 of the present invention is provided.
A third aspect of the present invention provides the lactone-containing resin according to any one of the first to second aspects, wherein the lactone resin in the lactone-containing resin has a gel fraction of 0.01 to 90%. 4 of the present invention
Provides the lactone-containing resin according to any one of claims 1 to 3, wherein the other biodegradable resin is a synthetic and / or natural polymer. 5) The lactone-containing composition according to 4), wherein the synthetic polymer comprises an aliphatic polyester, a biodegradable cellulose ester, a polypeptide, a polyvinyl alcohol, an ethylene-vinyl acetate copolymer, or a mixture thereof. Provide resin. In the sixth aspect of the present invention, the natural polymer is starch, cellulose, paper, pulp, cotton, hemp, wool,
The lactone-containing resin according to 4 of the present invention, which comprises silk, leather, carrageenan, chitin / chitosan, natural linear polyester-based resin, or a mixture thereof. According to a seventh aspect of the present invention, there is provided a lactone-containing resin composition comprising the lactone-containing resin (c) according to any one of the first to sixth aspects of the present invention and a resin additive (d). 8 of the present invention is a resin additive is a plasticizer, a heat stabilizer, a lubricant, an antiblocking agent, a nucleating agent, a photodegradation agent, a biodegradation accelerator, an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, A lactone-containing resin composition according to 7 of the present invention, which is a dropping agent, an antibacterial agent, a deodorant, a filler, a colorant, or a mixture thereof. According to a ninth aspect of the present invention, there is provided a molded product obtained by molding the lactone-containing resin according to the first to sixth aspects of the present invention or the lactone-containing resin composition according to the seventh to eighth aspects of the present invention. In the tenth aspect of the present invention, the molding is extrusion molding, injection molding,
The molded article according to 9 of the present invention, which is blow molding, calender molding, compression molding, transfer molding, thermoforming, flow molding, or lamination molding. 11 of the present invention is an inflation molding of the lactone-containing resin according to 1 to 6 of the present invention or the lactone-containing resin composition according to 7 to 8 of the present invention,
A film formed by T-die molding or calendar molding is provided. According to a twelfth aspect of the present invention, there is provided the film according to the eleventh aspect of the present invention, which is uniaxially or biaxially stretched.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The lactone resin used in the present invention is ε-caprolactone, 4-methylcaprolactone, 3,5,5-
Various methylated caprolactones such as trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-
Homopolymer of propiolactone, γ-butyrolactone, δ-valerolactone, enantholactone,
Copolymers of more than one kind of monomer, homopolymers of these or a mixture of the copolymers are exemplified. In particular, those which do not soften at room temperature are preferable, and from this viewpoint, they have a high molecular weight and a melting point of 60 ° C.
As described above, poly-ε-caprolactone, from which stable performance is easily obtained, is preferable.

The lactone resin according to the present invention will be described below using polycaprolactone as a typical example. The non-irradiated polycaprolactone preferably has a number average molecular weight of 10,000 to 500,000, and particularly preferably 30,000 to 200,000 from the viewpoint of efficient crosslinking. Polycaprolactone having the above molecular weight is obtained from JI
Relative viscosity 1.15 to 2.8 according to SK6726
0, particularly preferably 1.50-2.
80.

The lactone-containing resin (c) used in the present invention is a lactone resin (a) alone or a mixture of the lactone resin (a) and another biodegradable resin (b). As the other biodegradable resin, a synthetic and / or natural polymer is used. Examples of the synthetic polymer include aliphatic polyester, polyamide, polyamide ester, biodegradable cellulose ester, polypeptide, polyvinyl alcohol, and a mixture thereof. The synthetic aliphatic polyester resin is a polyester resin other than the lactone resin, and is an aliphatic polyester resin obtained by a condensation polymerization system. Hereinafter, the synthetic aliphatic polyester resin is simply referred to as an aliphatic polyester resin, and in the case of a naturally occurring resin, this is clearly indicated. Examples of the aliphatic polyester resin include biodegradable polyester resins such as synthetic polylactic acid, polyethylene succinate, and polybutylene succinate (such resins include low molecular weight aliphatic resins represented by Bionole of Showa Polymer Co., Ltd.). Examples thereof include polyester resins synthesized from dicarboxylic acids and low molecular weight aliphatic diols), and JP-A-9-2.
No. 35360, 9-2333956, terpolymer aliphatic polyesters described in JP-A-7-17772
No. 6, lactic acid and hydroxycarboxylic acid copolymers. As biodegradable cellulose esters,
Organic acid esters such as cellulose acetate, cellulose butyrate, and cellulose propionate; inorganic acid esters such as cellulose nitrate, cellulose sulfate, and cellulose phosphate;
Hybrid esters such as cellulose acetate butyrate, cellulose acetate phthalate and cellulose nitrate acetate can be exemplified. These cellulose esters can be used alone or in combination of two or more. Among these cellulose esters, organic acid esters, particularly cellulose acetate, are preferred. Examples of the polypeptide include polyamino acids such as polyglutamic acid and polyamide esters. Examples of polyamide esters include resins synthesized from ε-caprolactone and ε-caprolactam. As an example of the synthetic polymer, when an aliphatic polyester resin is used as an example, those having a number average molecular weight of 20,000 to 200,000, preferably 40,000 or more in terms of standard polystyrene by GPC can be used.

[0011] Natural polymers include starch, cellulose,
Paper, pulp, cotton, hemp, wool, silk, leather, carrageenan, chitin / chitosan, natural linear polyester resin, or a mixture thereof. Examples of the starch include raw starch, processed starch, and a mixture thereof. As raw starch, corn starch, potato starch, sweet potato starch,
Wheat starch, cassava starch, sago starch, tapioca starch, rice starch, legume starch, kudzu starch, bracken starch, lotus starch, sis starch, and the like. , Moist heat-treated starch, etc.), enzyme-modified starch (hydrolyzed dextrin, enzyme-decomposed dextrin, amylose, etc.), chemically-modified starch (acid-treated starch, hypochlorite-oxidized starch, dialdehyde starch, etc.), chemically-modified starch derivative ( Esterified starch, etherified starch, cationized starch, cross-linked starch, etc.). Among the above, as the esterified starch, acetate-starch, succinate-starch, nitrate-starch, phosphate-starch, urea-phosphate-starch, xanthate-starch, acetoacetate-starch Etc .; etherified starch such as allyl etherified starch, methyl etherified starch, carboxymethyl etherified starch, hydroxyethyl etherified starch and hydroxypropyl etherified starch; etc .; cationized starch includes starch and 2-diethylaminoethyl chloride , A reaction product of starch and 2,3-epoxypropyltrimethylammonium chloride, etc .; Examples of the crosslinked starch include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked starch, and acrolein crosslinked starch.

In the present invention, the lactone-containing resin composition comprises a lactone-containing resin (c) and a resin additive (d). As a resin additive, a plasticizer, a heat stabilizer, a lubricant, an antiblocking agent, a nucleating agent, a photolytic agent, a biodegradation accelerator, an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, a dropping agent,
Examples include antimicrobial agents, deodorants, fillers, colorants, or mixtures thereof.

Examples of the plasticizer include aliphatic dibasic acid esters, phthalic acid esters, hydroxy polycarboxylic acid esters, polyester plasticizers, fatty acid esters, epoxy plasticizers, and mixtures thereof. Specifically, di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), diisodecyl phthalate (D
Phthalic acid esters such as IDP), adipic acid-di-2-
Adipates such as ethylhexyl (DOA) and diisodecyl adipate (DIDA), azelaic acid-
Azelaic acid esters such as di-2-ethylhexyl (DOZ), tri-2-ethylhexyl acetylcitrate,
Polyester plasticizers such as hydroxy polyvalent carboxylate esters such as acetyl tributyl citrate and polypropylene glycol adipate esters, which are used alone or in a mixture of two or more. The addition amount of these plasticizers varies depending on the application, but is generally preferably in the range of 3 to 30 parts by weight based on 100 parts by weight of the lactone-containing resin (c). When it is a film, the range is preferably 5 to 15 parts by weight. If it is less than 3 parts by weight, elongation at break and impact strength will be low, and if it exceeds 30 parts by weight,
In some cases, the breaking strength and the impact strength may be reduced.

The heat stabilizer used in the present invention includes an aliphatic carboxylate. As the aliphatic carboxylic acid, an aliphatic hydroxycarboxylic acid is particularly preferred. As the aliphatic hydroxycarboxylic acid, naturally occurring ones such as lactic acid and hydroxybutyric acid are preferable. Examples of the salt include salts of sodium, calcium, aluminum, barium, magnesium, manganese, iron, zinc, lead, silver, copper, and the like. These can be used as one kind or as a mixture of two or more kinds. The addition amount is in the range of 0.5 to 10 parts by weight based on 100 parts by weight of the lactone-containing resin (c). When a heat stabilizer is used in the above range, impact strength (Izod impact value) is improved, elongation at break, strength at break,
This has the effect of reducing the variation in impact strength.

The lubricant used in the present invention includes an internal lubricant,
Those generally used as an external lubricant can be used. For example, fatty acid esters, hydrocarbon resins, paraffins, higher fatty acids, oxy fatty acids, fatty acid amides, alkylene bis fatty acid amides, aliphatic ketones, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, fatty alcohols, Examples include a hydric alcohol, polyglycol, polychrycerol, metal soap, modified silicone or a mixture thereof. Preferably, fatty acid esters, hydrocarbon resins and the like are used. When selecting a lubricant, it is necessary to select a lubricant whose melting point is lower than the melting point of the lactone resin or other biodegradable resin. For example, considering the melting point of the aliphatic polyester resin, the fatty acid amide is 160 ° C.
The following fatty acid amides are selected. For example, in the case of a film, 0.05 to 5 parts by weight of a lubricant is added to 100 parts by weight of the lactone-containing resin (c). If the amount is less than 0.05 part by weight, the effect is not sufficient, and if the amount is more than 5 parts by weight, the material is not wound around a roll, and the physical properties are deteriorated. From the viewpoint of preventing environmental pollution, ethylene bisstearic acid amide, stearic acid amide, oleic acid amide, and erucic acid amide, which are highly safe and are registered with the FDA (US Food and Drug Administration), are preferred for use in films. .

Examples of the photodegradation accelerator include benzophenones such as benzoins, benzoin alkyl ethers, benzophenone and 4,4-bis (dimethylamino) benzophenone and derivatives thereof; acetophenone,
Acetophenones such as α, α-diethoxyacetophenone and derivatives thereof; quinones; thioxanthones; photoexciting materials such as phthalocyanine, anatase-type titanium oxide, ethylene-carbon oxide copolymer, sensitization of aromatic ketones with metal salts And the like. These photolysis accelerators are
One type or two or more types can be used in combination.

Examples of the biodegradation accelerator include oxo acids (for example, oxo acids having about 2 to 6 carbon atoms such as glycolic acid, lactic acid, citric acid, tartaric acid, and malic acid), saturated dicarboxylic acids (for example, Organic acids such as lower saturated dicarboxylic acids having about 2 to 6 carbon atoms such as oxalic acid, malonic acid, succinic acid, succinic anhydride, glutaric acid and the like; these organic acids and alcohols having about 1 to 4 carbon atoms; Lower alkyl esters. Preferred biodegradation promoters include organic acids having about 2 to 6 carbon atoms, such as citric acid, tartaric acid, and malic acid, and coconut shell activated carbon. One or more of these biodegradation accelerators can be used in combination.

In the present invention, at least the lactone resin (a) constituting the lactone-containing resin (c) has been subjected to a predetermined radiation irradiation treatment. In the present invention, "the component lactone resin has been subjected to radiation irradiation alone or together with at least one other component" means that the lactone resin (a) alone and the lactone resin (a) are used alone. Irradiated before molding, during molding, or after molding in the state of a mixture with another biodegradable resin (b) and a state where at least one resin additive (d) is blended with the lactone-containing resin (c). Means that. Further, the shape may be a powder, a pellet, a molding state, or a product state. Therefore, in the present invention, the lactone resin alone is subjected to a predetermined irradiation treatment in advance, to which, for example, a synthetic aliphatic polyester resin is mixed, or a resin composition obtained by further adding a fatty acid amide or the like, a lactone resin And a mixture of a synthetic aliphatic polyester resin or a fatty acid amide and the same radiation irradiation treatment, followed by mixing the remaining components to obtain a resin composition, a lactone resin, a synthetic aliphatic polyester resin and a fatty acid amide. The resin composition obtained by the irradiation treatment is also included. Further, for example, as an embodiment in which the three components are mixed and then subjected to radiation irradiation treatment, an embodiment of irradiating a composition (for example, a strand for pellet production) at the time of producing pellets for molding may also be used during film formation. The mode of irradiating the film of
The mode of irradiating a molded article is also included. Gel fraction is 0.01
By irradiating so as to be 10 to 10%, preferably 0.05 to 5.0%, crosslinking occurs and the melting point increases,
The tensile strength and the tear strength are improved, the releasability from the mold and the roll adhesion are reduced, and the transparency is increased. In addition, a mode in which irradiation is performed at a low dose first and then a high dose is performed at a later stage is also included. For example, the gel fraction is 0.01 to 10 in the pellet stage.
%, Preferably 0.05 to 5.0%, and 5 to 90% during molding or after molding, preferably 10 to 9%.
Irradiation can be performed so as to be 0%. This allows
Since the melt viscosity is higher than that of the unirradiated material, it is possible to maintain the shape at a higher temperature and irradiate again, and the crosslinking occurs with a high probability and the heat resistance is improved.

The radiation source used in the radiation irradiation treatment according to the present invention includes α-rays, β-rays, γ-rays, X-rays, electron beams,
Ultraviolet rays and the like can be used, but γ-rays, electron beams, and X-rays from cobalt 60 are more preferable. Among them, γ-rays, electron beam irradiation treatment using an electron accelerator is useful for introducing a bridge structure of a polymer material. Most convenient.

The irradiation amount is determined using a gel fraction of a lactone resin as a measure for introducing a crosslinked structure of a polymer material as one measure. When irradiating the lactone resin before molding, the gel fraction is 0.01 to 10% in consideration of moldability.
For example, about 0.1 to 3% is preferable for a film. When irradiating a molded article, the gel fraction of the lactone resin can be as high as about 90%. When the gel fraction is set to 10% or more, since crosslinking occurs mainly in the amorphous region of the polymer material, a large dose of, for example, 200 kGy is required in the irradiation treatment near room temperature, and in the treatment near the melting point, There is a tendency for a large number of voids to occur and reduce the strength. Therefore, in such a case, the lactone resin is melted at a temperature higher than the melting point (60 ° C. for polycaprolactone) and does not lead to crystallization after melting (for polycaprolactone, 50 ° C.).
(−35 ° C.). By performing the above treatment in this state, a gel with a very high gel fraction can be obtained at a low dose. As described above, one of the radiation irradiation treatment conditions is specified as “a state that does not lead to crystallization after melting”. The “state that does not lead to crystallization” as used herein means “a state that does not lead to crystallization” The degree of conversion is 5% or less. " In addition, not only the treatment with the lactone resin alone, but also the treatment with the above various compositions comprising other components, it is sufficient to consider only the molten state of the lactone resin component.

As a result of observing the effect of the radiation treatment of the lactone resin in the present invention, when the gel fraction and the melt index (MI) of the degree of crosslinking were measured, the effect began to appear when the irradiation dose reached 10 kGy. The gel fraction shows a sharp rise at 100 kGy, the MI further decreases at 60 kGy, and tends to be stable at higher doses. For biodegradability,
As a result of measurement in sludge, the higher the radiation irradiation dose, the higher the decomposition rate. In addition, biodegradation was started by immersion for 4 to 5 days, and a result of 50% was obtained after about 10 days. In addition, improvements in mechanical properties (tensile strength, tensile elongation, tear strength, impact strength) and anti-blocking properties of the film against nip rolls were also observed.

In the present invention, various molded articles can be obtained by molding a lactone-containing resin or a lactone-containing resin composition. The primary molding into pellets, plates, parisons, etc., and then forming them into sheets, films, tapes, thin-walled containers, thick-walled containers (including uniaxially or biaxially stretched products, improving transparency and mechanical strength by stretching) ), Fiber (including stretched material, stretching improves transparency and mechanical strength.)
Into a bag, especially a degradable garbage bag, a draining bag, a shrink film (which may be formed directly), a perforated film, etc .; a laminated film into an agricultural multi-film, etc .; Threads, ropes, fabrics, fishing lines, nets, etc .; tapes for packing tapes, nets, bands, etc .; nets for civil engineering reinforcement, planting, diapers, sanitary products, medical products nets; thin-walled containers Into trays, blister packs, etc .; thick containers into bottles, planting containers, etc .; daily necessities such as hoses and pipes, industrial materials; foam into cushioning materials, agricultural materials, etc .; It can be processed into cards, information media materials, outdoor goods, sports goods, leisure goods, etc. Examples of the molding method include extrusion molding, injection molding, blow molding, calendar molding, compression molding, transfer molding, thermoforming, flow molding, and lamination molding.

A preferred example in the case of forming a film, particularly a film by an inflation method, will be described below. First, the compounding ratio of the lactone resin and the aliphatic polyester resin is 30 to 5% by weight of the former and 30 to 5% by weight of the latter.
95% by weight (total 100% by weight of both) is preferred,
In this case, it is particularly preferable that the upper limit of the former is 60% by weight or less, and the upper limit of the latter is 60 to 10% by weight.
A range of -90% by weight is preferred. In this case, if the lactone resin exceeds 70% by weight, the mechanical properties at high temperature of a molded product such as a film tend to decrease, and if it is less than 5% by weight, disintegration based on biochemical decomposition may decrease. The same can be said for the case where this tendency is out of the range of 40 to 10% by weight. On the other hand, if the amount of the aliphatic polyester resin exceeds 95% by weight, the biodegradability tends to be slow. On the other hand, if the amount is less than 30% by weight, the heat resistance may decrease when processed into a film, for example. is there. The same can be said for the case where this tendency is out of the range of 60 to 90% by weight. The blending ratio of fatty acid amide as a lubricant is
The total amount of the lactone resin and the aliphatic polyester resin is preferably from 0.2 to 5 parts by weight based on 100 parts by weight in total, but from 0.3 to 5 parts by weight.
A range of 1.5 parts by weight is more preferred. If the fatty acid amide is less than 0.2 parts by weight, the effect of blocking in the tube of the blown film or the effect of preventing blocking between the film and the nip roll or guide roll is slightly lowered,
On the other hand, when the amount exceeds 5 parts by weight, the slipperiness of the film is apt to be increased more than necessary, and in addition to the problem of collapse of the roll winding, the printability, adhesiveness, and the like also begin to decrease. Further, if necessary, a liquid lubricant, fine powder silica, starch and the like can be added. The purpose of using the liquid lubricant is that the lactone resin or the aliphatic polyester resin as the resin component constituting the resin composition is supplied to the inflation film forming step usually in the form of pellets or beads, and the bulk specific gravity thereof is extremely small as described below. When trying to mix finely powdered silica etc. uniformly,
This is because it is preferable to keep the surfaces of the pellets and beads as wet as possible. The amount of the liquid lubricant having such a purpose of use is preferably 0.1 to 3 parts by weight, more preferably 0.2 to 0.1 part by weight, based on 100 parts by weight of the total amount of the lactone resin and the aliphatic polyester resin. It is added in the range of 7 parts by weight. If the added amount exceeds 3 parts by weight, a large amount of the liquid lubricant adheres to the inner surface of the mixing tumbler, and sticky and stable mixing may be difficult. If the added amount is less than 0.1 part by weight, the effect as a wetting agent is sufficient. May not be able to demonstrate. This tendency is more favorable for 0.1.
It is also found outside the range of 2 to 0.7 parts by weight. on the other hand,
The liquid lubricant as a wetting agent preferably has a melting point of 70 ° C. or lower, and a liquid lubricant at room temperature is more preferably used. For example, in addition to liquid paraffin, paraffin wax, stearyl alcohol, stearic acid, etc., stearic acid esters such as butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, stearyl stearate and the like can be mentioned.
The most preferred liquid paraffin in the above-mentioned liquid lubricant is very safe since its oral acute toxicity (rat) LD50 is 5 g / kg, is recognized as a food additive by the Food Sanitation Law, and is discarded after use of the film. It is a very convenient material in terms of prevention of environmental pollution in the event that it occurs. As described above, a liquid lubricant was selected as the lubricant, but if a solid lubricant is used, the entire system including the resin composition needs to have a melting point of the solid lubricant or higher, and a low temperature of the melting point or lower. It is difficult to use. Liquid paraffin, which is liquid at room temperature, is a preferred lubricant in this regard. The purpose of using the finely divided silica is to prevent the above-mentioned blocking at the time of forming the blown film and the blown film according to the present invention. The fine powdered silica used may be silica produced by a wet method, silica produced by high-temperature hydrolysis of silicon tetrachloride in an oxyhydrogen flame, and the like, particularly those having a particle size of 50 nm or less. Is preferred. As the addition method, the method of heating and kneading a resin composition containing the lactone resin according to the present invention, a composition comprising a lactone resin and an aliphatic polyester resin or a resin composition further adding a fatty acid amide is most preferable. A considerably high shearing force acts to loosen the secondary agglomerated particles, thereby exhibiting an effect of blocking between films and between a film and each roll and preventing stickiness. In addition, the addition amount of the fine powder silica is most preferably in the range of 0.1 to 3 parts by weight based on 100 parts by weight of the mixture of the lactone resin and the aliphatic polyester resin in view of the above effects.

As a method for obtaining a blended composition obtained by adding the various additives to the biodegradable resin composition, various methods conventionally used can be applied, and are not particularly limited. For example, to explain an example of a method for producing the above-mentioned composition, first, a lactone resin and an aliphatic polyester resin and a liquid lubricant are put into a tumbler, and then the lactone resin is used for 10 to 20 minutes.
Then, the fatty acid amide is added, and the fine powder silica and starch are added thereto, and the mixture is further stirred and mixed for 20 to 30 minutes. After that, a 14 or single screw extruder or the like is used.
Melt kneading is performed at about 0 to 210 ° C. to obtain powder or pellets of the resin composition containing various additives. As described above, the irradiation treatment may be appropriately performed in this step.

The melt fluidity of a biodegradable resin composition comprising a lactone resin, an aliphatic polyester resin and a fatty acid amide subjected to the above-mentioned specific irradiation treatment is particularly limited as long as the resin composition can be subjected to a film forming process. Although not necessarily performed, MI (load 21 at 190 ° C.)
(Measured at 60 g) is preferably 0.3 to 20 g / 10 min, and particularly preferably 0.5 to 3 g / 10 min. Next, the film formation will be described. The raw resin composition is supplied to an extruder provided with an annular die, melted and kneaded at a temperature of about 180 ° C., and extruded into a tube from an annular die slit. At this time, the extrusion diameter of the extruder is 40 to 65 m
m, a length / diameter ratio (L / D) of 26 to 32, an annular die having a diameter of 50 to 150 mm can be adopted, and a gap of the die slit is preferably in a range of 0.5 to 1.5 mm. The extruded tubular unsolidified blown film expands to a predetermined diameter by setting the blow ratio (tube diameter / die diameter) to 2 or more by the pressure of the gas introduced from the gas blowing pipe inserted through the die. Then, it is folded by a nip roll and taken up at a constant speed, and is wound up as a tubular film or cut in the taking-up direction and taken as a wide film. The resin composition obtained through the radiation treatment step can stably produce a film regardless of the temperature of the resin extruded from the annular die, possibly due to the crosslinked structure of the lactone resin. According to the present invention, the additive-containing resin composition in the form of powder or pellets is compared with a conventional lactone resin or a composition thereof without irradiation treatment, by improving the melt viscosity which is considered to be based on the crosslinked structure. It can also be applied to various conventional molding methods other than the inflation film forming method.

When the film is formed into a film, the MI of the lactone resin after irradiation is 0.3 or less (ie, a low gel fraction).
The degree of cross-linking is preferable, and when irradiating a molded article such as a housing or a flower pot, the degree of cross-linking is such that the MI is 0.1 or less (that is, a high gel fraction). Good. Further, depending on the product, before the molding, a crosslinking is carried out to slightly raise the melting point and to maintain the MI at 0.1 or more, and then molded into the shape of the final product.
Cross-linking can be performed as follows.

[0027]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In the Examples, “%” and “parts” are based on weight unless otherwise specified. The melt index (MI) is a value indicating the flow characteristics under a load of 2160 g at 190 ° C. First, in addition to the above-described effects of the radiation irradiation treatment of polycaprolactone of the lactone resin according to the present invention, a more specific description will be given using reference examples.

REFERENCE EXAMPLE 1 Polycaprolactone pellets (melt index: 2.57 g / 10 min) were heated to a melting point or higher and then cooled to 50.degree. Upon irradiation, the resulting treated pellets had a melt index of 0.05 g / 10 min (gel fraction 60 described below).
%) And 0.03 g / 10 min (gel fraction 80%). The untreated pellets and treated pellets were placed in an urban sewage sludge environment at 25 ° C. according to JIS K6950,
They were subjected to a 4-week biodegradability test. As a result, the decomposition rate of the non-irradiated product was 55%, while that of the irradiated product was 86.2% and 77.2%, respectively. Further, the irradiated product was formed into a sheet by a hot press at 200 ° C., and a biodegradability test was similarly performed on the pulverized sample. as a result,
The decomposition rates were 87.0% and 87.8%, respectively. The same test results were obtained by changing the irradiation type from electron beam to gamma ray.

Reference Example 2 The polycaprolactone used in Reference Example 1 was irradiated with an electron beam at a dose of 15 kGy at room temperature. Processed pellets (melt index is 1.0
g / 10 min, gel fraction 0.2%) was extruded with an extruder (resin temperature 150 ° C.) provided with a 40 mmφ T-die to obtain a sheet having a thickness of about 270 μm. The obtained sheet was subjected to a tear test, an impact strength test and JIS at room temperature.
A tensile test was performed according to K6782, and the results were compared with the test results of an unirradiated product similarly formed into a sheet. As a result, the tensile strength (MD: longitudinal direction) was 260, 280 kgf · cm, and the transverse direction (TD) in the order of the unirradiated product and the irradiated product.
Are 210 and 230 kgf · cm, and the tensile elongation (MD) is 1
130, 1240%, TD is 1130, 1160%,
The tear strength (MD) is 160, 270 gf, and the TD is 19
0, 450 gf, impact strength test 23.8, 25.2
kgf · cm respectively.

Reference Example 3 An electron beam was applied to the polycaprolactone used in Reference Example 1 at room temperature at 10, 20, 40, 10
Irradiation at 0 kGy was performed to measure changes in MI and gel fraction (%), and the following values were obtained in order. Electron beam dose (kGy): 0, 10, 20, 40, 100 MI (g / 10 min): 2.6, 1.0, 0.5, 0.1, 0.08 Gel fraction (%): 0, 0.1, 0.2, 0.3, 23.7

In Reference Examples 1 to 3, irradiation was examined for polycaprolactone to which biodegradable resin Bionole was added, but there was essentially no change.

A sample obtained by cutting a sheet obtained from 20 kGy-irradiated caprolactone in Reference Example 3 into a 10 cm square was immersed in warm water at 70 ° C., and the shrinkage was measured. As a result, the sheet obtained from unirradiated caprolactone was melted, but the 20 kGy irradiated sheet was shrunk by 60% in the MD direction and 30% in the TD direction without melting.

(Preparation of Biodegradable Resin Composition) [Preparation Example 1] Polycaprolactone (Placcel H7, trade name, manufactured by Daicel Chemical Industries, Ltd., number average molecular weight 1.2)
10 g of 8 × 10 ⁵ ) pellets were placed in a 1.5 cm diameter glass ampule, which was connected to a vacuum line to remove air, and then sealed. This sample was completely melted in an oven at 80 ° C., inserted into a metal block adjusted to 45 ° C. in advance, and irradiated with 100 kGy at a dose rate of 10 kGy / hr by gamma rays from cobalt 60. After the irradiation, the glass ampule was opened, and a cylindrical PCL having a diameter of 1.5 cm was taken out. From this, cut out a thin plate about 5mm thick,
Wrap in 200 mesh stainless steel wire mesh
It was immersed for 2 hours, and the gel fraction (the ratio of insolubles, which indicates the degree of crosslinking) was determined by the following equation, and was 70%. Gel fraction _{(%) = (W 2 /} W 1) × 100 ( wherein, W ₁ represents the dry weight of the PCL before immersion, W ₂
Represents the dry weight after immersion. Further, in order to examine the heat resistance, PCL sliced to a thickness of 2 to 3 mm was compression-molded into a film by hot pressing at 200 ° C., and the obtained film was extremely excellent in transparency. For heat resistance, a tensile strength and an elongation at break were determined using a high-temperature tensile tester under the conditions of a tensile speed of 100 mm / min and 120 ° C. The results are shown in Table 1. 40 parts of polycaprolactone, 60 parts of poly-1,4-butanediol-succinate, which had been subjected to an irradiation treatment step adjusted to have the same gel fraction as the irradiation, and liquid paraffin 0.1 part.
5 parts and 1 part of stearic acid amide were put into a twin screw type vented extruder (40 mm diameter), and extruded at a die temperature of 180 ° C. to obtain a resin composition pellet. The MI of this resin composition was 0.1 g / 10 min.

[Preparation Example 2] The gel fraction (%) of polycaprolactone obtained through the same step as the irradiation step described in Preparation Example 1 was 82%, except that irradiation was performed with γ-ray at a dose of 150 kGy. . Further, a heat resistance test was conducted by the method described in Preparation Example 1, and the results are shown in Table 1. After the irradiation step, 40 parts of polycaprolactone, 60 parts of poly-1,4-butanediol-succinate, and liquid paraffin 0.1 part were used.
5 parts, stearic acid amide 0.8 parts and fine powder silica (“Aerosil # 200” manufactured by Nippon Aerosil Co., Ltd.) 0.8
In the same manner as in Preparation Example 1 except for using the parts, pellets of the resin composition were obtained. The MI of this resin composition was 0.09 g / 10 min.

[Preparation Example 3] 40 parts of polycaprolactone and poly 1, which had undergone the same irradiation step as described in Preparation Example 2,
Resin composition as in Preparation Example 1 using 60 parts of 4-butanediol-succinate, 0.5 parts of liquid paraffin, 0.5 parts of stearamide and 0.5 parts of finely divided silica (Aerosil # 200). A product pellet was obtained. The MI of this resin composition was 0.09 g / 10 min.

[Preparation Example 4] 40 parts of polycaprolactone, poly 1, which had undergone the same irradiation step as in Preparation Example 2,
Preparation Example 1 using 60 parts of 4-butanediol-succinate, 0.5 part of liquid paraffin, 0.5 part of stearic acid amide, 0.5 part of finely divided silica (Aerosil # 200), and 50 parts of corn starch In the same manner as in the above, pellets of the resin composition were obtained. The MI of this resin composition is 0.09
g / 10 min.

[Comparative Preparation Example 1] 40 parts of unirradiated polycaprolactone, 60 parts of poly 1,4-butanediol-succinate, 0.5 part of liquid paraffin, 0.8 part of stearic acid amide, fine powdered silica (Japan Pellets of the resin composition were obtained in the same manner as in Preparation Example 1 using 0.8 parts of "Aerosil # 200" manufactured by Aerosil Co., Ltd. The melt index of this resin composition was 3.9 g / 10 minutes.

(Examples 1-4, Comparative Example 1) Preparation Examples 1
4. Using the pellets of the resin composition prepared in Comparative Preparation Example 1, an inflation film having a folding diameter (width) of 650 mm was formed by an inflation film forming method under the following forming conditions. (Molding conditions) Extruder: 40 mm diameter extruder Screw: L / D = 28, screw for MDPE (medium density polyethylene) Die: lip diameter 150 mm, die gap 1 mm Extrusion temperature: 170 ° C. at cylinder tip Die temperature: 170 ° C. Resin temperature (T1): 160 ° C. Screw rotation speed: 15 rpm Discharge amount: 15 kg / hr Blow ratio: 2.5 Inflation film formation was performed using each of the resin compositions of Preparation Examples 1 to 4, but stable production was performed. A film was formed, and a film having excellent biodegradability was obtained. Also, a film could be formed from the raw material using the resin composition of Comparative Preparation Example 1, but the film was merely a film having conventional performance because there was no effect of the irradiation treatment.

[0039]

[Table 1]

[0040]

According to the present invention, a decomposable resin and a decomposable resin having excellent decomposability, moldability and mechanical properties by forming a crosslinked structure in the lactone resin by subjecting the lactone resin to a specific radiation treatment. Compositions, moldings, and films are obtained. In particular, the melting point increases, and molding and use are possible at a higher temperature than before, and the decomposability is also improved. In the case of an inflation film, it is possible to provide a stable inflation film by performing irradiation treatment. The obtained film has excellent decomposability and is used for environmentally friendly packaging materials, agricultural films and the like.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Mitomo 1-5-1, Tenjin-cho, Kiryu-shi, Gunma Gunma University Faculty of Engineering (72) Inventor Dharmawan Dalwis 1-5-1, Tenjin-cho, Kiryu-shi, Gunma Gunma University Faculty of Engineering (72) Inventor Tadashi Murakami 1-323 Shinmatsudo Minami, Matsudo City, Chiba Prefecture

Claims (12)

[Claims] 1. A lactone-containing resin (c) comprising a lactone resin (a) alone or a lactone resin (a) and another biodegradable resin (b), wherein the lactone-containing resin (c)
The component lactone resin is used alone or with at least one other.
A lactone-containing resin, which has been subjected to a radiation irradiation treatment together with the components described in the above. 2. The method according to claim 1, wherein the lactone resin (a) is ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone,
The lactone-containing resin according to claim 1, which is a homopolymer of δ-valerolactone or enantholactone, a copolymer of two or more of these monomers, or a mixture of these homopolymers or copolymers. 3. The lactone-containing resin according to claim 1, wherein the gel fraction of the lactone resin in the lactone-containing resin is 0.01 to 90%. 4. The lactone-containing resin according to claim 1, wherein the other biodegradable resin is a synthetic and / or natural polymer. 5. The lactone-containing resin according to claim 4, wherein the synthetic polymer comprises an aliphatic polyester, a biodegradable cellulose ester, a polypeptide, a polyvinyl alcohol, or a mixture thereof. 6. The natural polymer may be starch, cellulose, paper,
The lactone-containing resin according to claim 4, comprising pulp, cotton, hemp, wool, silk, leather, carrageenan, chitin / chitosan, natural linear polyester resin, or a mixture thereof. 7. A lactone-containing resin composition comprising the lactone-containing resin (c) according to claim 1 and a resin additive (d). 8. The resin additive may be a plasticizer, a heat stabilizer, a lubricant,
Antiblocking agent, nucleating agent, photolytic agent, biodegradation accelerator,
The lactone-containing resin composition according to claim 7, which is an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant, a droplet, an antibacterial agent, a deodorant, a filler, a colorant, or a mixture thereof. 9. A molded product obtained by molding the lactone-containing resin according to claim 1 or 6 or the lactone-containing resin composition according to claim 7 or 8. 10. Molding includes extrusion molding, injection molding, blow molding, calender molding, compression molding, transfer molding,
The molded product according to claim 9, which is thermoforming, flow molding, or lamination molding. 11. A film obtained by inflation molding, T-die molding or calender molding of the lactone-containing resin according to claim 1 or the lactone-containing resin composition according to claim 7 or 8. 12. The film according to claim 11, which is uniaxially or biaxially stretched.