JP5827550B2 - Tubular laminate formed by laminating layers made of a molded product formed from degradable resin, and method for producing the same - Google Patents

Description

  The present invention relates to a tubular laminate formed by laminating a layer made of a decomposable resin having decomposability in an aqueous solvent on the outer surface of a tubular body substrate having a through-hole in a tube wall, and And a method for producing the tubular laminate.

  In recent years, wells for taking out oil, gas, water, hot water, hot springs, etc. from the ground and conducting water quality surveys to secure energy resources and protect the environment (hereinafter collectively referred to as “wells”) The need for drilling is increasing. In order to drill a well, for example, an oil well, using a device for drilling a well, that is, an oil well, a steel pipe called a casing is buried in the borehole, usually by drilling from the ground surface to a predetermined depth. Prevent the walls from collapsing. After that, from the tip of the casing, the basement is further excavated to make a deeper well, a new casing is embedded through the previously embedded casing, the diameter of the casing is adjusted as necessary, and this operation is repeated until the final An oil well pipe that reaches the oil reservoir is laid. Depending on the excavation method, the casing may not be used.

  From the finished oil well pipe, it is necessary to discharge the production fluid such as oil to the surface of the ground while separating it from gravel, sand, etc. Correspondingly sized through holes are provided in the tube wall. For example, an oil well pipe that collects oil to be produced is appropriately provided with a screen having a through-hole penetrating the pipe wall so that sand or the like is not mixed with the produced oil to be produced (Patent Document 1). Also, in a well for groundwater sampling for conducting water quality surveys, a tubular water sampling casing having a strainer formed on the tube wall is used in order to permeate the groundwater (Patent Document 2).

  With respect to these tubular bodies for well drilling devices, the holes such as a mesh provided in the screen or strainer are closed in the well drilling process, and foreign substances such as sand can enter the tubular body. In addition, after completion of the well, it is required that a predetermined number of fine through holes exist with a predetermined size so that foreign substances can be separated or separated. Further, the through holes provided in the casing are closed until they are embedded at a predetermined position, and after being embedded at a predetermined position, a predetermined number of through holes having a predetermined size are provided. Is required to appear. For example, in a well drilling process, if the screen of the oil well pipe is not completely blocked and sand or other foreign matter may be clogged, it may be necessary to repeat the screen cleaning process after completion of the well. Or, because of insufficient cleaning, the oil well pipe screen is clogged in a short period of time, resulting in a decrease in production efficiency or the need to replace the oil well pipe in a short period of time. There was also a big problem.

  For this reason, it is known to impregnate the filtering layer of the screen of the oil well pipe with a temporary seal substance, and as the temporary seal substance, there is a degradable polymer. Degradable polymers include polysaccharides, chitin, chitosan, protein, aliphatic polyester, polylactide, polyglycolide, poly-ε-caprolactone, polyhydroxybutyrate, aliphatic polycarbonate, polyorthoester, polyamino acid, polyethylene oxide Or polyphosphazene is known (Patent Document 3). However, Patent Document 3 does not disclose a specific disclosure of a specific degradable polymer selection method, a temporary sealing material impregnation method, and a temporary sealing material treatment method after disposal.

  Therefore, not only the tubular body for a well drilling device but also a tubular body having a member such as a screen or a strainer formed by a through-hole penetrating the tube wall, that is, a tubular body having a through-hole in the tube wall. , If necessary, it is easy to close and securely open, especially, no special operation is required to open, the process is reduced, and further, after opening the through hole, There has been a demand for a tubular article that can easily dispose of a waste material such as a material used for closing or opening a through-hole, and a method for producing the same.

Japanese Unexamined Patent Publication No. 7-48893 JP 9-41869 A US Patent Application Publication No. 2005/155757

  An object of the present invention is to make it easy to reliably close and reliably open a through-hole as necessary for a tubular body having a through-hole in a tube wall. No operation is required, the number of processes is reduced, and, after opening the through-hole, the material that becomes waste in the disposal of materials used to close or open the through-hole affects the environment. Therefore, an object of the present invention is to provide a tubular article that does not require or can be easily processed, and a method for manufacturing the tubular article.

  As a result of intensive research on solving the above-mentioned problems, the present inventors formed a decomposable resin having decomposability in an aqueous solvent on the outer surface of the tubular body substrate having a through hole in the tube wall. The present invention has been completed by finding that the problem can be solved by laminating layers of molded products to be formed into a tubular laminate.

  That is, according to the present invention, a tube formed by laminating a layer made of a molded product formed from a degradable resin that is decomposable in an aqueous solvent on the outer surface of a tubular body substrate having a through hole in the tube wall. A laminate is provided.

  Moreover, according to this invention, the tubular laminated body of the following (1)-(9) is provided as an embodiment.

(1) The said tubular laminated body whose degradable resin is a biodegradable resin.
(2) The said tubular laminated body whose biodegradable resin is biodegradable polyester.
(3) The tubular laminate described above, wherein the biodegradable polyester is a biodegradable aliphatic polyester.
(4) The tubular laminate described above, wherein the biodegradable aliphatic polyester is at least one selected from the group consisting of polyglycolic acid, polylactic acid, glycolic acid-lactic acid copolymer, and mixtures thereof.
(5) The tubular laminate described above, wherein the layer made of a molded product formed from a degradable resin has a weight reduction rate of 50% or more after being immersed in water at a temperature of 90 ° C. for 1 week.
(6) The said tubular laminated body whose molded article is a film or a textile product.
(7) The said tubular laminated body whose film is at least 1 sort (s) chosen from the group which consists of an unstretched film, a stretched film, and a heat shrink film.
(8) The said tubular laminated body whose textiles are at least 1 sort (s) chosen from the group which consists of a nonwoven fabric, a woven fabric, a knitted fabric, and a long fiber yarn.
(9) The said tubular laminated body whose tubular body base material which has a through-hole in a pipe wall is a tubular body for well drilling apparatuses.

  Furthermore, according to the present invention, the following production methods (I) to (III) are provided as methods for producing the tubular laminate.

(I) After a heat-shrinkable film formed from a degradable resin is wound around the outer surface of a tubular base material having through holes in the tube wall, the film is heated to a temperature equal to or higher than the heat-shrink temperature of the heat-shrinkable film. A method for producing the tubular laminate, comprising heat-shrinking a heat-shrinkable film to obtain a heat-shrinkable film.
(II) A method for producing the tubular laminate, comprising winding a stretched film formed from a degradable resin around an outer surface of a tubular body substrate having a through hole in a tube wall.
(III) A method for producing the tubular laminate, comprising winding a long fiber yarn formed from a degradable resin around an outer surface of a tubular substrate having a through hole in a tube wall.

  According to the present invention, a layer made of a molded product formed from a degradable resin that is decomposable in an aqueous solvent is laminated on the outer surface of a tubular body substrate having a through hole in a tube wall. In order to open the through hole of the tubular body having a through hole in the tube wall, if necessary, it is easy to reliably close and reliably open the hole. Special operations have been reduced (process reduction), and after opening the through-holes, substances that become waste are disposed of in the environment against the disposal of materials used to close or open the through-holes. There is an effect that a tubular article that does not need to be treated or is easy to process because it is not affected is provided.

  Furthermore, according to the present invention, the tubular laminate can be easily obtained by including wrapping a film or the like formed from a degradable resin around the outer surface of the tubular base material having a through hole in the tube wall. The effect that the manufacturing method of the tubular laminated body which can be provided is provided.

1. Degradable resin having decomposability in aqueous solvent The degradable resin having decomposability in the aqueous solvent constituting the tubular laminate of the present invention can be decomposed by heating in the presence of an aqueous solvent, if necessary. It is a resin that can be used.

  A degradable resin having decomposability in an aqueous solvent (hereinafter sometimes simply referred to as “degradable resin”) can be decomposed in an aqueous solvent, that is, in water or a mixed solvent containing water. . When water containing inorganic compounds such as salt existing in nature is used as an aqueous solvent, or when used as mud for well drilling, the composition is adjusted according to the purpose of drilling. You may contain an inorganic compound etc.

  Examples of the degradable resin having decomposability in an aqueous solvent include polysaccharides, chitin, chitosan, polyester, polycarbonate, polyorthoester, polyamino acid, polyether, and polyphosphazene. Among these degradable resins, biodegradable resins having a low environmental load are preferable because they are biodegraded by microorganisms or enzymes existing in nature such as soil and water. Moreover, among the degradable resins having degradability in an aqueous solvent, biodegradable polyesters are more preferable, and among them, biodegradable aliphatic polyesters are suitably hydrolyzed in environments such as well drilling, Moreover, since decomposition | disassembly is accelerated | stimulated by an acid or a base, the adjustment and control of the working time are also possible in a well drilling process, and it is more preferable.

2. Biodegradable polyesters Biodegradable polyesters include aliphatic polyesters, copolymerized polyesters of aromatic polyesters and aliphatic polyesters, and mixtures thereof. For these biodegradable polyesters, various compounds can be copolymerized, combined by polymer reaction, or mixed within the range that does not impair degradability and biodegradability. Also good. Furthermore, these biodegradable polyesters can also be used in a composite form by mixing with other materials, etc., as substances that develop degradability and biodegradability.

(1) Biodegradable aliphatic polyester Particularly preferred biodegradable aliphatic polyesters include polyglycolic acid (hereinafter sometimes referred to as “PGA”) composed of glycolic acid repeating units and polylactic acid composed of lactic acid repeating units. Hydroxycarboxylic acid polyesters such as lactic acid (hereinafter sometimes referred to as “PLA”), lactone polyesters such as poly-ε-caprolactone, diol / dicarboxylic acid polyesters such as polyethylene succinate and polybutylene succinate, and These copolymers, for example, copolymers composed of glycolic acid repeating units and lactic acid repeating units (glycolic acid-lactic acid copolymer), and mixtures thereof are known.

  Among biodegradable aliphatic polyesters, PLA is obtained from L-lactic acid, which is a raw material, at low cost by fermentation from corn, straw, etc. The performance of the obtained polymer is characterized by high rigidity and good transparency. In addition to being excellent in hydrolyzability and biodegradability, PGA is characterized by excellent mechanical strength such as heat resistance and tensile strength. For this reason, PGA is expected to be used as an agricultural material, various packaging (container) materials, etc., and has been developed for use alone or in combination with other resin materials.

  PGA and PLA are suitable for the production of the laminate, that is, the molding process, in order to obtain the tubular laminate of the present invention, and reliably block the through holes provided in the tube wall of the tubular laminate as necessary. It is particularly preferable in that it is suitable for exhibiting physical properties such as sufficient mechanical strength and is moderately hydrolyzed in an environment such as well drilling.

  The biodegradable aliphatic polyester will be further described in detail. The biodegradable aliphatic polyester constituting the tubular laminate of the present invention is glycolic acid and glycolic acid containing glycolide (GL) which is a bimolecular cyclic ester of glycolic acid; lactic acid and a bimolecular cyclic ester of lactic acid. In addition to lactic acids including lactide; ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactones (eg, β-propiolactone, β-butyrolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), carbonates (such as trimethylene carbonate), ethers (such as 1,3-dioxane), ether esters (such as dioxanone) Cyclic monomers such as 3-hydroxypropanoic acid, 4-hydroxybutanoic acid Hydroxycarboxylic acids such as 6-hydroxycaproic acid or alkyl esters thereof; aliphatic diols such as ethylene glycol and 1,4-butanediol (butylene glycol); and aliphatic dicarboxylic acids such as succinic acid and adipic acid or alkyls thereof Includes substantially equimolar mixtures with esters; homopolymers or copolymers of aliphatic ester monomers such as; Specifically, for example, the formula: (—O—CHR—CO—) [R is a hydrogen atom or a methyl group. ] The biodegradable aliphatic polyester which has 50 mass% or more of the glycolic acid or lactic acid repeating unit represented by these, polylactone, polyhydroxybutyrate, polyethylene succinate, polybutylene succinate, etc. are mentioned. Of these, biodegradable aliphatic polyesters having 50% by mass or more of glycolic acid or lactic acid repeating units are preferable. Specifically, PGA, that is, a homopolymer of glycolic acid, or a copolymer having 50% by mass or more of glycolic acid repeating units; PLA, that is, a homopolymer of poly L-lactic acid or poly D-lactic acid, L A copolymer having 50% by mass or more of repeating units of lactic acid or D-lactic acid, or a mixture thereof; a glycolic acid-lactic acid copolymer; and a mixture thereof as described above; and a mixture of PGA and PLA; Is preferred. Particularly preferred is PGA or PLA from the viewpoints of hydrolyzability, biodegradability, heat resistance and mechanical strength.

  These biodegradable aliphatic polyesters can be synthesized, for example, by dehydration polycondensation of α-hydroxycarboxylic acids such as glycolic acid and lactic acid known per se. In order to efficiently synthesize a high molecular weight biodegradable aliphatic polyester, generally, a method of synthesizing a bimolecular cyclic ester of α-hydroxycarboxylic acid and subjecting the cyclic ester to ring-opening polymerization is employed. . For example, PLA is obtained by ring-opening polymerization of lactide, which is a bimolecular cyclic ester of lactic acid. PGA is obtained by ring-opening polymerization of glycolide, which is a bimolecular cyclic ester of glycolic acid.

  PLA can be synthesized by the above-mentioned method. Examples of commercially available products include “Lacia” (registered trademark) series (such as Lacia H-100, H-280, H-400, H-440) ( “Mt. "Ecoplastic U'z series" (manufactured by Toyota Motor Corporation), "Viro Ecole" (registered trademark) (manufactured by Toyobo Co., Ltd.), etc., such as S-17, etc. From the viewpoint, it is preferably selected.

  Hereinafter, the biodegradable aliphatic polyester will be further described mainly using PGA as an example, but PLA and other biodegradable aliphatic polyesters can also take a form for carrying out the invention according to PGA. .

[Polyglycolic acid (PGA)]
The PGA that is particularly preferably used as the PGA constituting the tubular laminate of the present invention is a homopolymer of glycolic acid (glycolic acid) consisting only of glycolic acid repeating units represented by the formula: (—O—CH ₂ —CO—) (Including a ring-opened polymer of glycolide (GL), which is a bimolecular cyclic ester), and a PGA copolymer containing 50% by mass or more of the glycolic acid repeating unit.

  Examples of comonomers that give a PGA copolymer together with glycolic acid monomers such as glycolide include ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactides, lactones, carbonates, and ethers. , Ether esters, amides and other cyclic monomers; lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6-hydroxycaproic acid and other hydroxycarboxylic acids or alkyl esters thereof; ethylene glycol A substantially equimolar mixture of an aliphatic diol such as 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof; or two or more of these Can do. These comonomers can be used as a starting material for giving a PGA copolymer together with the glycolic acid monomer such as glycolide.

  The glycolic acid repeating unit in the PGA constituting the tubular laminate of the present invention is 50% by mass or more, preferably 70% by mass or more, more preferably 85% by mass or more, still more preferably 95% by mass or more, particularly preferably. Is a PGA homopolymer of 98% by weight or more, most preferably 99% by weight or more. If the ratio of glycolic acid repeating units is too small, the strength and biodegradability expected for PGA will be poor. The repeating unit other than the glycolic acid repeating unit is 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less, still more preferably 5% by mass or less, and particularly preferably 2% by mass or less. Most preferably, it is used in a proportion of 1% by mass or less, and may not contain any repeating unit other than the glycolic acid repeating unit.

  The PGA constituting the tubular laminate of the present invention is obtained by polymerizing 50 to 100% by mass of glycolide and 50 to 0% by mass of the other comonomer described above in order to efficiently produce a desired high molecular weight polymer. PGA is preferred. The other comonomer may be a cyclic monomer between two molecules, or may be a mixture of both instead of a cyclic monomer. In order to obtain a tubular laminate intended by the present invention, a cyclic monomer is used. Is preferred. Hereinafter, PGA obtained by ring-opening polymerization of 50 to 100% by mass of glycolide and 50 to 0% by mass of other cyclic monomers will be described in detail.

[Glycolide]
Glycolide that forms PGA by ring-opening polymerization is a bimolecular cyclic ester of glycolic acid, which is a kind of hydroxycarboxylic acid. Although the manufacturing method of glycolide is not specifically limited, Generally, it can obtain by thermally depolymerizing a glycolic acid oligomer. As a thermal depolymerization method for glycolic acid oligomers, for example, a melt depolymerization method, a solid phase depolymerization method, a solution depolymerization method or the like can be employed, and glycolide obtained as a cyclic condensate of chloroacetate is also used. be able to.

  The PGA constituting the tubular laminate of the present invention may be formed by ring-opening polymerization of only glycolide, but may also be formed by simultaneously ring-opening polymerization using another cyclic monomer as a copolymerization component. Good. In the case of forming a copolymer, the proportion of glycolide is 50% by mass or more, preferably 70% by mass or more, more preferably 85% by mass or more, still more preferably 95% by mass or more, and particularly preferably 98% by mass. % Or more, and most preferably 99% by mass or more of a substantially PGA homopolymer.

[Other cyclic monomers]
Other cyclic monomers that can be used as a copolymerization component with glycolide include lactones (for example, β-propiolactone, β-butyrolactone, in addition to bimolecular cyclic esters of other hydroxycarboxylic acids such as lactide). Cyclic monomers such as pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, trimethylene carbonate, 1,3-dioxane and the like can be used. Other preferable cyclic monomers are bimolecular cyclic esters of other hydroxycarboxylic acids. Examples of hydroxycarboxylic acids include L-lactic acid, D-lactic acid, α-hydroxybutyric acid, α-hydroxyisobutyric acid, α- Hydroxyvaleric acid, α-hydroxycaproic acid, α-hydroxyisocaproic acid, α-hydroxyheptanoic acid, α-hydroxyoctanoic acid, α-hydroxydecanoic acid, α-hydroxymyristic acid, α-hydroxystearic acid, and these Examples include alkyl-substituted products. Another particularly preferable cyclic monomer is lactide, which is a bimolecular cyclic ester of lactic acid, and may be any of L-form, D-form, racemate, and a mixture thereof.

  The other cyclic monomer is 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less, still more preferably 5% by mass or less, particularly preferably 2% by mass or less, and most preferably 1% by mass. Used in the following proportions. When PGA is formed from 100% by weight of glycolide, the other cyclic monomer is 0% by weight, and this PGA is also included in the scope of the present invention. By ring-opening copolymerization of glycolide and other cyclic monomers, the melting point of PGA (copolymer) is lowered to lower the processing temperature, and the crystallization speed is controlled to improve extrusion processability and stretch processability. can do.

(Ring-opening polymerization reaction)
The ring-opening polymerization or ring-opening copolymerization of glycolide (hereinafter sometimes collectively referred to as “ring-opening (co) polymerization”) is preferably carried out in the presence of a small amount of a catalyst. Although the catalyst is not particularly limited, for example, a tin-based compound such as tin halide (for example, tin dichloride, tin tetrachloride, etc.) or organic carboxylate (for example, tin octoate such as tin 2-ethylhexanoate). A titanium compound such as alkoxy titanate; an aluminum compound such as alkoxyaluminum; a zirconium compound such as zirconium acetylacetone; an antimony compound such as antimony halide and antimony oxide; The amount of the catalyst used is preferably 1 to 1,000 ppm, more preferably 3 to 300 ppm in terms of mass ratio with respect to the cyclic ester.

  Ring-opening (co) polymerization of glycolide is a protic property such as higher alcohols such as lauryl alcohol, diols such as ethylene glycol, other alcohols and water in order to control the physical properties such as molecular weight and melt viscosity of the produced PGA. The compound can be used as a molecular weight regulator. Glycolide usually contains trace amounts of water and hydroxycarboxylic acid compounds composed of glycolic acid and linear glycolic acid oligomers as impurities, and these compounds also act on the polymerization reaction. Therefore, the concentration of these impurities is quantified as a molar concentration by, for example, neutralizing titration of the amount of carboxylic acid in these compounds, and based on this quantified value, alcohols or The molecular weight and the like of the produced PGA can be adjusted by adding water and controlling the molar concentration of all protic compounds with respect to glycolide. Moreover, you may add polyhydric alcohols, such as glycerol, for a physical property improvement.

  The ring-opening (co) polymerization of glycolide may be bulk polymerization or solution polymerization, but in many cases, bulk polymerization is employed. There are various types of polymerization equipment for bulk polymerization, such as an extruder type, a vertical type with paddle blades, a vertical type with helical ribbon blades, a horizontal type such as an extruder type and a kneader type, an ampoule type, a plate type and a tubular type. The device can be selected as appropriate. Moreover, various reaction tanks can be used for solution polymerization.

  The polymerization temperature can be appropriately set according to the purpose within a range from 120 ° C. to 300 ° C. which is a substantial polymerization start temperature. The polymerization temperature is preferably 130 to 270 ° C, more preferably 140 to 260 ° C, and particularly preferably 150 to 250 ° C. If the polymerization temperature is too low, the molecular weight distribution of the produced PGA tends to be wide. If the polymerization temperature is too high, the produced PGA is susceptible to thermal decomposition. The polymerization time is in the range of 3 minutes to 50 hours, preferably 5 minutes to 30 hours. If the polymerization time is too short, the polymerization does not proceed sufficiently and a predetermined molecular weight cannot be realized. If the polymerization time is too long, the produced PGA tends to be colored.

  After making the produced PGA into a solid state, solid phase polymerization may be further carried out if desired. The solid phase polymerization means an operation of performing heat treatment while maintaining a solid state by heating at a temperature lower than the melting point (Tm) of PGA described later. By this solid phase polymerization, low molecular weight components such as unreacted monomers and oligomers are volatilized and removed. The solid phase polymerization is preferably performed for 1 to 100 hours, more preferably 2 to 50 hours, and particularly preferably 3 to 30 hours.

  When the tubular laminate of the present invention is provided with a layer of a molded article formed from PGA, in addition to PGA, other aliphatic polyesters; polyethylene glycol, polypropylene glycol, etc. Other resins such as polyethers; modified polyvinyl alcohols; polyurethanes; polyamides such as poly L-lysine; plasticizers, antioxidants, heat stabilizers, end-capping agents, ultraviolet absorbers, lubricants, mold release Additives that are usually blended, such as fillers, waxes, colorants, crystallization accelerators, hydrogen ion concentration regulators, fillers such as reinforcing fibers, and the like can be blended as necessary. Moreover, additives, such as an antibacterial agent, a disinfectant, and a fungicide, can be mix | blended as needed. The compounding amount of these other resins and additives is usually 50 parts by mass or less, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and 5 parts by mass or less or 1 part by mass with respect to 100 parts by mass of PGA. The following blending amount may be sufficient.

  In particular, it is preferable to add a carboxyl group end-capping agent or a hydroxyl group end-capping agent to PGA, since the weather resistance, heat resistance and long-term storage stability of the tubular laminate are improved. That is, by adding a carboxyl end-capping agent or a hydroxyl end-capping agent, the hydrolysis resistance during storage before using the tubular laminate for the intended purpose is improved, and the molecular weight during storage is reduced. While being able to suppress, the degree of biodegradability at the time of disposal can be adjusted. As the terminal blocking agent, a compound having a carboxyl group terminal blocking action or a hydroxyl group terminal blocking action and known as a water resistance improver for aliphatic polyesters can be used. From the viewpoint of the balance between hydrolysis resistance during storage, decomposability in an aqueous solvent, and biodegradability, a carboxyl group end-capping agent is particularly preferred. Examples of the carboxyl group end capping agent include carbodiimide compounds such as N, N-2,6-diisopropylphenylcarbodiimide; 2,2′-m-phenylenebis (2-oxazoline), 2,2′-p-phenylene Oxazoline compounds such as bis (2-oxazoline), 2-phenyl-2-oxazoline and styrene / isopropenyl-2-oxazoline; oxazine compounds such as 2-methoxy-5,6-dihydro-4H-1,3-oxazine; And epoxy compounds such as N-glycidylphthalimide, cyclohexene oxide, and tris (2,3-epoxypropyl) isocyanurate; Among these carboxyl group end-capping agents, carbodiimide compounds are preferred, and aromatic, alicyclic, and aliphatic carbodiimide compounds are also used, but aromatic carbodiimide compounds are particularly preferred, and those with particularly high purity are used. Gives water resistance improvement effect during storage. Moreover, as a hydroxyl group terminal blocker, a diketene compound, isocyanates, etc. are used. The carboxyl group terminal blocking agent or the hydroxyl group terminal blocking agent is usually 0.01 to 5 parts by mass, preferably 0.05 to 3 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of PGA. It is used in the ratio.

  In addition, it is more preferable to add a heat stabilizer to PGA because thermal deterioration during processing can be suppressed and the long-term storage stability of the tubular laminate is further improved. As thermal stabilizers, cyclic neopentanetetraylbis (2,6-di-tert-butyl-4-methylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) ) Phosphate, phosphate ester having a pentaerythritol skeleton structure such as cyclic neopentanetetraylbis (octadecyl) phosphite; mono- or di-stearyl acid phosphate, or a mixture thereof, preferably having 8 to 8 carbon atoms Phosphoric acid alkyl ester or phosphorous acid alkyl ester having 24 alkyl groups; Metal carbonates such as calcium carbonate and strontium carbonate; Bis [2- (2-hydroxybenzoyl) hydrazine] generally known as a polymerization catalyst deactivator Dodecanoic acid, N, N ' Hydrazine compounds having a -CONHNH-CO- unit such as bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine; 3- (N-salicyloyl) amino-1,2, And triazole compounds such as 4-triazole; triazine compounds; and the like. A heat stabilizer is 3 mass parts or less normally with respect to 100 mass parts of PGA, Preferably it is 0.001-1 mass part, More preferably, it is 0.005-0.5 mass part, Most preferably, it is 0.01-0. It is used at a ratio of 1 part by mass (100 to 1,000 ppm).

(2) Copolymer polyester of aromatic polyester and aliphatic polyester As the biodegradable polyester, a copolymer polyester of an aromatic polyester and an aliphatic polyester can also be preferably used. As copolymer polyester of aromatic polyester and aliphatic polyester, as aromatic polyester component, polyalkylene terephthalates such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polypropylene isophthalate, polybutylene isophthalate, etc. Polyalkylene isophthalates, polyethylene naphthalate, polypropylene naphthalate, polybutylene naphthalate, and other polyalkylene naphthalates, polyesters having cyclohexanedimethanol as a diol component, and trivalent or higher alcohols to these polyesters Polyesters copolymerized as necessary, and copolymer polyesters that combine two or more of these polyesters Having like ethers, also, as the aliphatic polyester component include those having a like same polyesters as biodegradable aliphatic polyester shown above. Examples of commercially available biodegradable polyesters comprising copolymerized polyesters of aromatic polyesters and aliphatic polyesters include Biomax (registered trademark) (manufactured by DuPont) and Ecoflex (registered trademark) (manufactured by BASF). From the viewpoint of strength, flexibility, heat resistance and the like, it is preferably selected.

3. Properties of degradable resin, etc. [average molecular weight (Mw)]
The average molecular weight (Mw) of the degradable resin constituting the tubular laminate of the present invention is not particularly limited. For example, the average molecular weight (Mw) in the case of PGA is 20,000 or more, preferably within the range of 2 to 1,000,000, more preferably 5 to 800,000, still more preferably 70 to 600,000, particularly Preferably, the one in the range of 100,000 to 400,000 is selected. In the present invention, the average molecular weight (Mw) of the degradable resin is a weight average molecular weight determined using a gel permeation chromatography (GPC) analyzer. For example, when the degradable resin is PGA, the PGA sample is dissolved in hexafluoroisopropanol (HFIP) in which sodium trifluoroacetate is dissolved at a predetermined concentration, and then filtered through a membrane filter to obtain a sample solution. The average molecular weight (Mw) is calculated from the result of injecting this sample solution into the GPC analyzer and measuring the molecular weight. Moreover, when the degradable resin which comprises the tubular laminated body of this invention is PLA, the average molecular weight (Mw) of PLA becomes like this. Preferably it is 5 to 1 million, More preferably, it is 6 to 800,000, More preferably, it is 7 to 60 It is in the range of 10,000.

[Melt viscosity]
The melt viscosity of the decomposable resin constituting the tubular laminate of the present invention is not particularly limited. For example, in the case of PGA, it is usually 100 to 10,000 Pa · s, preferably 200 to 8,000 Pa · s, more preferably 300 to 4,000 Pa · s, and still more preferably 400 to 3,000 Pa · s. It is. If the melt viscosity of the degradable resin is too small, mechanical properties such as strength of the tubular laminate are insufficient, and long-term storage stability may be insufficient. The melt viscosity of the decomposable resin is measured under conditions of a melting point (Tm) of the decomposable resin + 20 ° C. and a shear rate of 122 sec ⁻¹ .

[Melting point (Tm)]
The melting point (Tm) of the decomposable resin constituting the tubular laminate of the present invention is not particularly limited. For example, the melting point (Tm) of PGA is usually 197 to 245 ° C., and can be adjusted by the average molecular weight (Mw), the type and content ratio of the copolymer component, and the like. The melting point (Tm) of PGA is preferably 200 to 240 ° C, more preferably 205 to 235 ° C, and particularly preferably 210 to 230 ° C. The melting point (Tm) of the homopolymer of PGA is usually about 220 ° C. The melting point (Tm) of PLA is preferably 140 to 190 ° C, more preferably 145 to 185 ° C, and still more preferably 150 to 175 ° C. If the melting point (Tm) of the decomposable resin is too low, the heat resistance and strength of the tubular laminate may be insufficient. If the melting point (Tm) is too high, the processability for forming a film or long fiber yarn may be insufficient, or the formation of the tubular laminate may not be sufficiently controlled. The melting point (Tm) of the decomposable resin is determined in a nitrogen atmosphere using a differential scanning calorimeter (DSC). Specifically, a degradable resin sample such as PGA is detected in a temperature rising process of heating from room temperature to a temperature near melting point (Tm) + 60 ° C. at a temperature rising rate of 20 ° C./min in a nitrogen atmosphere. It means the temperature of the endothermic peak accompanying crystal melting. When a plurality of absorption peaks are observed, the peak having the largest endothermic peak area is defined as the melting point (Tm).

[Glass transition temperature (Tg)]
The glass transition temperature (Tg) of the decomposable resin constituting the tubular laminate of the present invention is not particularly limited. For example, the glass transition temperature (Tg) of PGA is usually 25 to 60 ° C, preferably 30 to 50 ° C, more preferably 35 to 45 ° C. The glass transition temperature (Tg) of PGA can be adjusted by the average molecular weight (Mw), the type and content ratio of the copolymer component, and the like. The glass transition temperature (Tg) of the decomposable resin was determined in a nitrogen atmosphere using a differential scanning calorimeter (DSC) as in the measurement of the melting point (Tm). Specifically, a degradable resin sample such as PGA is detected in a temperature rising process of heating from room temperature to a temperature near melting point (Tm) + 60 ° C. at a temperature rising rate of 20 ° C./min in a nitrogen atmosphere. The onset temperature of the second order transition in the second order transition region corresponding to the transition region from the glass state to the rubber state is defined as the glass transition point (Tg). When the glass transition temperature (Tg) is too low, the surface of the obtained tubular laminate is excessively softened, and the heat resistance and strength of the tubular laminate may be insufficient. If the glass transition temperature (Tg) is too high, moldability may be deteriorated.

  Moreover, when the degradable resin which comprises the tubular laminated body of this invention is PLA, the glass transition temperature (Tg) of PLA becomes like this. Preferably it is 45-75 degreeC, More preferably, it is 50-70 degreeC, More preferably, it is 55-55. It is in the range of 68 ° C.

4). Layer formed of a molded product formed from a degradable resin having decomposability in an aqueous solvent The tubular laminate of the present invention is a layer formed from a molded product formed from a degradable resin such as a biodegradable aliphatic polyester ( Hereinafter, it may be referred to as “degradable resin molded product layer”). The decomposable resin molded product layer is a resin molded product layer mainly composed of a decomposable resin containing 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more of the decomposable resin.

  The tubular laminate of the present invention comprises one or more decomposable resin molded product layers, and may comprise two or more layers. The thickness of the degradable resin molded product layer is usually 1 μm to 30 mm, preferably 3 μm to 25 mm, more preferably 5 μm to 20 mm, and even more preferably 10 μm to 15 mm, and the molded product formed from a tubular laminate or a decomposable resin. The optimum range can be determined according to If the thickness of the degradable resin molded product layer is less than 1 μm or exceeds 30 mm, the tubular laminate targeted by the present invention cannot be obtained. When the tubular laminate includes two or more decomposable resin molded product layers, the thickness of the decomposable resin molded product layer means the total thickness of the decomposable resin molded product layers.

  The molded article formed from the degradable resin is not particularly limited as long as it can be laminated on the outer surface of the tubular base material having through holes in the tube wall, but mechanical strength such as strength of the tubular laminated body is not limited. It is preferably a molded article having properties, long-term storage, excellent degradability in an aqueous solvent, biodegradability, and the like, and specifically, the molded article is preferably a film or a textile product.

  In the present invention, the film is a general term for films and sheets. In addition, the textile product is a generic term for fabrics and long fiber yarns, and the fabric is a generic term for woven fabrics, knitted fabrics, nonwoven fabrics, etc., and the long fiber yarns have a very large length with respect to the diameter. By continuous filament yarn is meant monofilament yarn or multifilament yarn. Hereinafter, the decomposable resin molded product layer will be described in detail with respect to the case where the molded product is a film or a long fiber yarn.

(1) Layer made of a film formed from a decomposable resin A layer made of a film formed from a decomposable resin provided in the tubular laminate of the present invention (hereinafter sometimes referred to as “degradable resin film layer”). Is in the range of 1 μm to 30 mm, preferably 3 μm to 20 mm, more preferably 5 μm to 15 mm, and even more preferably 10 μm to 10 mm. If the thickness of the decomposable resin film layer is too small, mechanical properties such as strength of the tubular laminate and preservability before use may be insufficient. If the thickness of the degradable resin film layer is too large, the processability of the film may be poor, the adhesiveness with the tubular body substrate may be insufficient, and the time required for hydrolysis or biodegradation may be too long. There is. The decomposable resin film layer may be a layer formed from a single film, and has a necessary thickness by stacking thin films having the same or different thicknesses from the viewpoint of processability and ease of manufacture. A layer may be formed. The number of thin films to be stacked can be appropriately selected in the range of 2 to 20, and in many cases the range of 5 to 15 is suitable.

  The film formed from the degradable resin used to form the degradable resin film layer (hereinafter sometimes referred to as “degradable resin film”) is an unstretched film, a stretched film, or a heat-shrinkable film. A heat shrinkable film obtained by heating and heat shrinking can be used.

[Unstretched film formed from degradable resin and method for producing the same]
The thickness of the undegradable resin unstretched film is preferably 1 μm to 3 mm, more preferably 5 μm to 2 mm, still more preferably 10 μm to 1.5 mm, particularly preferably 20 μm to 1 mm, and most preferably 30 to 500 μm. Can do. As described above, since the decomposable resin film layer can be formed from one or a plurality of films, the thickness of the decomposable resin unstretched film means the total thickness of the decomposable resin unstretched film. To do.

  As a method for forming an unstretched film by forming a resin mainly composed of a degradable resin, a known method for producing a film can be employed. For example, on a cooling drum in which the resin mainly composed of the decomposable resin is melted in an extruder and then extruded from a T die or the like, and the surface temperature is adjusted to 0 to 50 ° C., and in many cases 10 to 30 ° C. A decomposable resin unstretched film can be obtained by bringing it into close contact with and quenching.

[Stretched film formed from degradable resin and method for producing the same]
A stretched film formed from a degradable resin (hereinafter sometimes referred to as a “degradable resin stretched film”) is a uniaxially stretched or unstretched film obtained by forming a resin mainly composed of a degradable resin. A biaxially stretched film. From the viewpoints of mechanical properties such as strength of the tubular laminate and uniformity of thickness, a biaxially stretched film is preferable.

  As a method for forming an unstretched film by forming a resin mainly composed of a degradable resin, a known method for producing a film can be employed in the same manner as described for the unstretchable resin unstretched film. As a method for producing a degradable resin stretched film from the obtained unstretched film, a known stretched film production method can be employed. For example, as a uniaxial stretching method, longitudinal stretching by roll stretching can be used. As a biaxial stretching method, a flat sequential biaxial stretching, a flat simultaneous biaxial stretching, a tubular simultaneous biaxial stretching, or the like can be used. Is uniform, flat sequential biaxial stretching and flat simultaneous biaxial stretching are preferred. When sequential biaxial stretching is used, a method of stretching in the longitudinal direction in the first stage and stretching in the transverse direction in the second stage can be mentioned.

  The draw ratio of the degradable resin stretched film is preferably 4 times or more, more preferably 6 times or more, and still more preferably 8 times or more as the surface magnification. When the surface magnification is less than 4 times, defects may occur in physical properties such as occurrence of thickness spots and insufficient strength. The upper limit of the surface magnification is not particularly limited, but it is usually 20 times or less, and in many cases 18 times or less, from the viewpoint that the stretched film does not break or the decomposability is not uniform. . In the present invention, the surface magnification refers to the product of the stretching ratio in the longitudinal direction and the stretching ratio in the transverse direction. When multi-stage stretching is performed in one direction, all the stretching ratios are multiplied. Continuous multi-stage stretching in the same direction is treated as one-stage stretching. For example, when the film is continuously stretched 1.2 times in the longitudinal direction and then 1.5 times, the stretching in the longitudinal direction is 1.8 times.

  The temperature of the film at the time of stretching, that is, the stretching temperature, is preferably in the range of glass transition temperature (Tg) + 2 ° C. to Tg + 25 ° C., more preferably Tg + 2 ° C. to Tg + 20 ° C., and more preferably Tg + 2 ° C. to Tg + 15 ° C. It is a range. This temperature range needs to be applied in all stretching steps in the case of sequential biaxial stretching. If the stretching temperature is out of this temperature range, the film may be broken during stretching, or the neck may be stretched to increase the thickness unevenness.

  The degradable resin stretched film can be heat-set by heat treatment, if necessary, in a heated atmosphere or in contact with a hot platen, preferably under tension. The temperature of the heat treatment may be Tg + 20 ° C. to Tm−20 ° C., preferably Tg + 30 ° C. to Tm−30 ° C., preferably Tg + 40 ° C. to Tm−40 ° C. The time for performing the heat treatment is about 5 seconds to 5 minutes, more preferably about 10 seconds to 3 minutes. By this heat treatment, the molecular orientation in the stretched film is fixed and thermal shrinkage is suppressed. If the heat treatment temperature is too low or the heat treatment time is too short, it will be difficult to perform sufficient heat setting, and the heat shrinkage resistance of the stretched film will decrease. If the stretched film is not heat-set, the film may be thermally contracted and the contracted portion may be whitened.

  The thickness of the degradable resin stretched film is preferably 1 μm to 3 mm, more preferably 5 μm to 2 mm, still more preferably 10 μm to 1.5 mm, particularly preferably 12 μm to 1 mm, and most preferably 15 to 500 μm. it can. As described above, since the decomposable resin film layer can be formed from one or a plurality of films, the thickness of the degradable resin stretched film means the total thickness of the degradable resin stretched film.

[Heat Shrink Film Formed from Degradable Resin and Method for Producing the Same]
A heat-shrinkable film formed from a decomposable resin is heated by heating a heat-shrinkable film formed from a decomposable resin and having heat-shrinkability (hereinafter, also referred to as “decomposable resin heat-shrinkable film”). It is a heat-shrinkable film obtained by shrinking. Decomposable resin heat-shrinkable film is formed in the same manner as the method for producing degradable resin unstretched film described above, after forming a resin mainly composed of degradable resin to obtain an unstretched film, and then unstretched The film can be obtained by uniaxial stretching or biaxial stretching. From the viewpoint of mechanical properties such as strength of the tubular laminate and uniformity of thickness, it is preferable to obtain by biaxial stretching. The stretching method and the stretching temperature are the same as those for obtaining a degradable resin stretched film. In order to provide heat-shrinkability, heat setting performed by heat-treating a stretched film is not usually performed, but if necessary, heat-decomposable resin heat can be obtained by performing heat treatment for a short time under relaxation or slight tension. The heat shrinkage rate of the shrinkable film can be adjusted.

  The draw ratio of the decomposable resin heat-shrinkable film is 1.2 to 4.0 times, preferably 1.3 to 3.5 times, more preferably 1.5 to 3.2 times, still more preferably as the surface magnification. Is in the range of 1.6 to 3.0 times. If the draw ratio is too small or too large, the thickness of the film after heat shrinkage may become uneven or the strength may be uneven.

  The decomposable resin heat-shrinkable film has a shrinkage rate in hot water of 90 ° C. for 10 seconds (hereinafter referred to as “hot-water shrinkage rate”) in the machine direction (MD) and / or the transverse direction (TD). It has a heat shrinkage performance of at least 10%, preferably 20% or more, more preferably 25% or more in at least one direction, preferably in two directions MD and TD. It is preferable that the upper limit of the hot water shrinkage is usually 50%, and in many cases 40%. When the hot water shrinkage rate is less than 10%, the adhesion to the tubular body substrate is deteriorated. On the other hand, when the hot water shrinkage rate exceeds 50%, the shrinkage stress becomes strong, the surface shape of the tubular laminate becomes non-uniform, and in extreme cases, the through holes of the tube wall are blocked excessively firmly. There is a fear. A specific method for measuring the hot water shrinkage of the decomposable resin heat-shrinkable film is as follows. That is, five sample films are cut out from one decomposable resin heat-shrinkable film, and the distance is 10 cm in the longitudinal direction (machine direction, MD) and lateral direction (direction perpendicular to the machine direction, TD) of each sample film. Mark at intervals. The sample film was immersed in water adjusted to a temperature of 90 ° C. for 10 seconds, then taken out, immediately cooled with normal temperature water, the marked distance was measured, and the shrinkage of the distance between the marks reduced from 10 cm The percentage of the previous distance (10 cm) is displayed as a percentage. About five decomposable resin heat-shrinkable films, the average values in the longitudinal direction and the transverse direction are determined and displayed as “hot water shrinkage (temperature 90 ° C.−10 seconds later)”.

  The thickness of the decomposable resin heat-shrinkable film is preferably 1 μm to 3 mm, more preferably 5 μm to 2 mm, still more preferably 10 μm to 1.5 mm, and particularly preferably 15 μm to 1.2 mm. As described above, since the decomposable resin film layer can be formed from one or a plurality of films, the thickness of the decomposable resin heat-shrinkable film is the total thickness of the decomposable resin heat-shrinkable film. Means.

  The decomposable resin heat-shrinkable film has a temperature equal to or higher than the heat-shrink temperature of the heat-shrinkable film, usually the glass transition temperature (Tg) of the decomposable resin + 20 ° C. or higher, preferably Tg + 23 ° C. or higher, more preferably Tg + 25 ° C. or higher. More preferably, it is heat-shrinkable by heating to a temperature of Tg + 27 ° C. or higher to obtain a heat-shrinkable film. The thickness of the heat-shrinkable film formed from the decomposable resin is substantially the same as the thickness of the decomposable resin heat-shrinkable film. The decomposable resin heat-shrinkable film is covered with a tubular base material, which will be described in detail later. Can be made. The upper limit of the heating temperature for performing heat shrinkage is usually the melting point (Tm) of the degradable resin -48 ° C, preferably Tm-, from the viewpoint of the uniformity of the surface of the layer of the degradable resin film formed after shrinkage. It is about 50 ° C. The time for performing heat shrinkage varies depending on the heating temperature, but is usually 5 seconds to 10 minutes, preferably 10 seconds to 8 minutes, and more preferably 20 seconds to 6 minutes.

(2) Layer composed of long fiber yarns formed from degradable resin A layer composed of long fiber yarns formed from a decomposable resin provided in the tubular laminate of the present invention (hereinafter referred to as “degradable resin long fiber yarn layer”). Is a layer formed from monofilament yarns or multifilament yarns which are long fiber yarns (hereinafter referred to as “degradable resin long fiber yarns”) formed from a degradable resin.

  The thickness of the degradable resin long fiber yarn layer is preferably in the range of 5 μm to 30 mm, more preferably 10 μm to 20 mm, still more preferably 20 μm to 15 mm, and particularly preferably 50 μm to 12 mm.

[Long fiber yarn formed from degradable resin and method for producing the same]
A long fiber yarn formed from a degradable resin, that is, a degradable resin long fiber yarn which is a monofilament yarn or a multifilament yarn can be obtained by employing a known long fiber yarn production method. For example, after a resin mainly composed of a decomposable resin is melted in an extruder, the resin is extruded into a thread form from a spinning nozzle and spun, rapidly cooled in a refrigerant adjusted to a temperature of 10 ° C. or less, and promptly Glass transition temperature (Tg) + 2 ° C. to Tg + 45 ° C., preferably Tg + 5 ° C. to Tg + 40 ° C., more preferably Tg + 10 ° C. to Tg + 35 ° C. A monofilament yarn formed from a decomposable resin can be produced by drawing twice or more, more preferably 3 times or more, and performing two-stage drawing or heat treatment if necessary. In order to produce a multifilament yarn formed from a degradable resin, a predetermined number of monofilament yarns, preferably 5 to 500 yarns, more preferably 10 to 100 yarns, are aligned and twisted by a usual method. The “monofilament yarn” or “multifilament yarn” may be referred to as “stretched monofilament yarn” or “stretched multifilament yarn”, and these may be collectively referred to as “stretched yarn”.

  The fineness of the long fiber yarn formed from the degradable resin is 0.5 to 100 denier for monofilament yarn, preferably 1.5 to 50 denier, and 5 to 10,000 denier for multifilament yarn, preferably 15 It may be about 5,000 denier.

5. Tubular body substrate having through holes in tube wall The tubular laminate of the present invention is formed by laminating the above decomposable resin molded product layer on the outer surface of a tubular body substrate having through holes in the tube wall. is there.

  The tubular body substrate having a through hole in the tube wall is a tubular article having a hole penetrating the inner and outer surfaces of the tube in the tube wall. The tube diameter of the tubular body substrate can be selected in the range of 1 cm to 1 m, often 5 to 70 cm, and usually 10 to 50 cm. The length of the tubular base material can be selected in the range of 5 cm to 100 m, in many cases 10 cm to 50 m, usually 20 cm to 10 m, but when used for various tests, the length is in the range of 25 cm to 1 m. May be used.

  There are no particular limitations on the number, shape, arrangement, etc. of the through-holes in the tubular base material having through-holes in the tube wall, that is, the holes penetrating the inner and outer surfaces of the tube. It is done. Examples of the shape of the through hole include a fine mesh shape, a mesh shape, a slit shape hole, a substantially circular hole having a diameter of about 1 mm to several cm, and the like. The arrangement of the through holes may be provided on almost the entire tube wall of the tubular body substrate, or may be provided on only a part of the tube wall, or may be provided on a plurality of parts.

  As the material of the tubular body base material having a through hole in the tube wall, hard plastics can be used in addition to metals such as stainless steel, aluminum, brass, bronze, copper, nickel, titanium, and alloys thereof. That is, the tubular body substrate is a metal tube or a resin tube. In some cases, the outer surface and / or the inner surface of the tubular body substrate may be subjected to a surface treatment with a rust preventive or a preservative.

  The size of the through hole of the tubular base material having a through hole in the tube wall is usually 200 mesh (aperture diameter about 0.13 mm) to 5 cm, preferably 150 mesh (aperture diameter about 0.17 mm) to 4 cm, More preferably, a mesh in the range of 100 mesh (aperture diameter of about 0.25 mm) to 3 cm can be employed. As the shape of the through hole, any shape such as a quadrangle (square, rectangle, rhombus, etc.), hexagon (tortoise shape), circle, ellipse or the like can be adopted. You may mix the through-hole from which direction differs in the same shape. The opening ratio of the through holes with respect to the surface area of the tube wall is in the range of 5 to 90%, preferably 10 to 85%, more preferably 15 to 80%. There is no limitation on the method of forming the through holes, and a method using perforation such as punching metal, a method in which a planar mesh body is rounded into a tubular body, a welded wire mesh, or the like is employed.

  Specifically, the tubular body substrate having a through hole in the tube wall includes a mesh filter, a tubular honeycomb, and a tubular body for a well drilling device (having a screen, a casing, and the like formed in the tube wall with a through hole). And a tubular body for a groundwater sampling device (having a strainer or the like formed in the tube wall with a through hole). In particular, a tubular body for a well drilling apparatus is preferably employed as the tubular body base material.

[Tubular body for well drilling equipment]
The tubular body for a well drilling device is a tubular body used for a well drilling device. As described above, the well drilling device is a device for drilling a well (“well”) that takes oil, gas, water, hot water, hot springs, and the like from the ground. In order to excavate a well, for example, an oil well, it is usually excavated from the ground surface to a predetermined depth, and a steel pipe called a casing is buried therein to prevent a wall from collapsing. After that, from the tip of the casing, drilling further underground to make a deeper well, burying a new casing through the previously embedded casing, expanding or deforming the casing as necessary, repeat this work, The oil well pipe that finally reaches the oil field will be laid.

  In the drilling process or from the finished oil well pipe, it is necessary to discharge oil and other production fluids, groundwater, excavated soil, gravel, sand, etc. to the surface while separating them separately. The tubular body for a well drilling device is provided with a through-hole having a size corresponding to the application in the tube wall. In particular, oil well pipes and the like for collecting produced oil are provided with appropriate screens made of fine mesh-like holes so that sand and the like are not mixed with the produced oil to be produced.

  The net-like holes provided in the screen of the oil well pipe and the like are closed in the well drilling process, so that foreign matters such as sand do not enter the inside of the tubular body, and are predetermined after the well is completed. It is required that foreign substances and the like can be separated and filtered so that a predetermined number of fine through holes exist with a size of 1 mm. In addition, the through hole provided in the casing or the like is buried in a predetermined position until it reaches a predetermined shape, and the through hole is closed, and after being embedded in a predetermined position and having a predetermined shape, It is required that a predetermined number of through holes appear in a predetermined size. For example, in a well drilling process, if the screen of the oil well pipe is not completely blocked and foreign matter such as sand may be clogged in the hole, it is necessary to repeat the screen cleaning process after completion of the well. Or because the cleaning of the oil well pipe is clogged in a short period of time due to insufficient cleaning, the production efficiency is reduced, or the oil well pipe needs to be replaced in a short period of time. There is also a big problem in gender.

6). Tubular laminate The tubular laminate of the present invention is obtained by laminating a decomposable resin molded product layer on the outer surface of a tubular base material having a through hole in a tube wall, such as a tubular body for a well drilling device such as a casing or an oil well pipe. It is the tubular laminated body characterized by being formed.

  The tubular laminate formed by laminating the decomposable resin molded product layer according to the present invention on the outer surface of the tubular substrate having a through-hole in the tube wall is formed by the tube of the tubular substrate with the decomposable resin molded product layer. A through hole provided in the wall is closed. Therefore, for example, when the tubular body base material is a tubular body for a well drilling device such as an oil well pipe, the screen of the tubular laminate of the present invention is blocked by sand, gravel, etc. in the drilling process. Can be reliably prevented, and after completion of the well, the decomposable resin molded product layer can be easily removed by decomposing the decomposable resin by treatment in an aqueous solvent. . As a result, a tubular body for a well drilling apparatus having a predetermined size and a predetermined number of fine through holes can be obtained on the pipe wall.

[Weight reduction rate in hot water]
The decomposable resin molded product layer in the tubular laminate of the present invention has a weight reduction rate after immersion in water at a temperature of 90 ° C. for 1 week (hereinafter sometimes referred to as “weight reduction rate in hot water”) at 50%. The above is preferable in practice. The weight reduction rate in hot water is more preferably 54% or more, further preferably 57% or more, particularly preferably 85% or more, and most preferably 90% or more. It can proceed efficiently. Needless to say, the upper limit of the weight reduction rate in hot water in the tubular laminate of the present invention is 100%.

  The measuring method of the weight decreasing rate in the hot water of the decomposable resin molded product layer in the tubular laminate is as follows. That is, a tubular laminate sample cut to a length of 20 cm was previously conditioned at a temperature of 23 ° C. and a relative humidity of 65% for 24 hours, and the weight of the tubular laminate was measured. The value obtained by subtracting the weight is defined as the weight of the decomposable resin molded product layer before treatment (referred to as “degradable resin weight before treatment”). Next, after immersing in water maintained at a temperature of 90 ° C. for 1 week, the humidity is adjusted for 24 hours at a temperature of 23 ° C. and a relative humidity of 65%, and the weight of the tubular laminate is measured. The subtracted value is defined as the weight of the decomposable resin molded product layer after treatment (referred to as “post-treatment degradable resin weight”). The weight reduction rate (%) in hot water is calculated as the ratio of the weight change (decrease weight) of the degradable resin molded product layer before and after the treatment to the predegradable resin weight. As water, distilled water or deionized water is used.

[Biodegradability]
Moreover, by making the degradable resin a biodegradable aliphatic polyester such as at least one selected from the group consisting of polyglycolic acid, polylactic acid, glycolic acid-lactic acid copolymer, and mixtures thereof, an aqueous system In addition to decomposing the decomposable resin by treating in a solvent, the decomposable resin is biodegraded in a short period of time in the soil, for example, after drilling a well, and disappears. The load can be greatly reduced.

  The biodegradability of the degradable resin molded product layer in the tubular laminate is evaluated according to ISO 14855 (aerobic compost test). Specifically, a tubular laminate sample cut to a length of 20 cm is embedded in soil adjusted to a temperature of 60 ° C. for 3 months, and biodegradability is evaluated from the amount of carbon dioxide generated at that time. If 50% or more of the degradable resin molded product layer of the tubular laminate has collapsed, it can be determined that the biodegradability is good.

  As described above, the tubular laminate of the present invention may include two or more decomposable resin molded product layers. By making the decomposable resin molded product layer into a different type of molded product or a combination of molded products of different thicknesses, the environment in which the tubular laminate is used (for example, composition of fluid, soil, etc., temperature , PH, etc.), a tubular laminate having properties such as hydrolyzability and biodegradability required can be obtained. As the combination of two or more degradable resin molded product layers, (i) a combination of a decomposable resin heat-shrinkable film and a decomposable resin long fiber yarn, (ii) stretching with different average molecular weights (Mw) of the degradable resin Examples of the combination of films include (iii) a combination of a thick layer formed from a stretched film having a high melt viscosity of a degradable resin and a thin layer formed from long fiber yarns having a low melt viscosity.

7). Method for producing tubular laminate The method for producing the tubular laminate of the present invention obtained by laminating the decomposable resin molded product layer on the outer surface of the tubular substrate having through holes in the tube wall is not particularly limited, From the viewpoint of manufacturing efficiency and thickness uniformity of the decomposable resin molded product layer, in particular, (1) a decomposable resin heat-shrinkable film is wound around the outer surface of a tubular body substrate having a through hole in the tube wall. After that, the heat shrinkable film is heated to a temperature equal to or higher than the heat shrink temperature of the heat shrinkable film to thermally shrink the heat shrinkable film, and (2) the decomposable stretched resin film has a through hole in the tube wall. A tubular laminate comprising winding the outer surface of a tubular body substrate having the structure, or (3) winding a long fiber yarn formed from a degradable resin around the outer surface of the tubular body substrate having a through hole in a tube wall. It is preferable that it is a manufacturing method. Hereinafter, the production methods (1) to (3) will be further described.

(1) After the decomposable resin heat-shrinkable film is wound around the outer surface of the tubular base material having through holes in the tube wall, the heat-shrinkable film is heated to a temperature equal to or higher than the heat-shrinkable temperature of the heat-shrinkable film. A method for producing a tubular laminate including heat shrinking a heat shrinkable film A tubular base material having a through hole in a tube wall obtained by cutting the degradable resin heat shrinkable film described above into a predetermined size One or a predetermined number of the outer surface of the tubular body base is lightly wound and covered, and then the heat-shrinkable film is contracted by heating to a temperature equal to or higher than the heat-shrink temperature of the heat-shrinkable film. This is a method for producing a tubular laminate including providing a decomposable resin molded product layer by bringing a decomposable resin heat-shrinkable film into close contact with the outer surface of the material to obtain a heat-shrinkable film. In addition, while winding the heat-shrinkable film from the roll of the heat-shrinkable film that has been prepared and manufactured to a predetermined width, it is wound around the tubular body substrate until the decomposable resin molded product layer has a predetermined thickness. Or a roll of a heat-shrinkable film produced by preparing a predetermined thickness of the degradable resin molded product layer in advance on the outer surface of the tubular body substrate having a through hole in the tube wall. A method of winding only the circumference may be used. When winding the heat-shrinkable film, it is preferable to wind the film while applying a certain tension to the film.

  Subsequently, the temperature above the heat shrink temperature of the heat shrinkable film, usually the glass transition temperature (Tg) of the degradable resin + 20 ° C. or higher, preferably Tg + 23 ° C. or higher, more preferably Tg + 25 ° C. or higher, more preferably Tg + 27 ° C. By heating to the above temperature, the heat-shrinkable film is heat-shrinked to obtain a tubular laminate. The decomposable resin heat-shrinkable film is loosely wound in advance on a tubular body base material that will be described in detail later, and the heat-shrinkable film is thermally shrunk and laminated with the tubular body base material. Integrate. The upper limit of the heating temperature for performing heat shrinkage is usually the melting point (Tm) of the degradable resin -48 ° C, preferably Tm-, from the viewpoint of the uniformity of the surface of the layer of the degradable resin film formed after shrinkage. It is about 50 ° C. The time for performing heat shrinkage varies depending on the heating temperature, but is usually 5 seconds to 10 minutes, preferably 10 seconds to 8 minutes, and more preferably 20 seconds to 6 minutes.

(2) A method for producing a tubular laminate including winding a degradable resin stretched film on the outer surface of a tubular substrate having a through hole in a tube wall. A tubular laminate including a decomposable resin-molded product layer provided on the outer surface of the tubular body base material by cutting it out and winding it around the outer surface of the tubular body base material having through holes in the tube wall is there. More specifically, as a method of using a thin degradable resin stretched film cut out to a predetermined dimension, the number of sheets necessary for the thickness of the decomposable resin molded product layer is accumulated in advance, and then the tubular substrate It may be wound around the outer surface, or the number of sheets necessary to make the thickness of the decomposable resin molded product layer the operation of winding the thin degradable resin stretched film one by one around the outer surface of the tubular body substrate, You may repeat until Moreover, you may wrap only 1 layer of the decomposable resin stretched film which was manufactured beforehand by adjusting to the thickness of the decomposable resin molded product layer around the outer surface of the tubular body substrate having through holes in the tube wall. Furthermore, the operation of unwinding the degradable resin stretched film from a roll of a thin degradable resin stretched film prepared in advance to a predetermined width and winding it around the tubular body substrate until the degradable resin molded product layer has a predetermined thickness. May be continued. Furthermore, a roll of a degradable resin stretched film produced by preparing a degradable resin molded product layer in advance to a predetermined thickness may be wound only once around the outer surface of a tubular body substrate having a through hole in the tube wall. Good. When winding a stretched film, it is preferable to wind the film while applying a certain tension to the film.

  Subsequently, in order to laminate and integrate the degradable resin stretched film and the tubular body base material, the degradable resin stretched film is wound around the outer surface of the tubular body base material having a through hole in the tube wall, and then if necessary. Then, while pressurizing from the outside, the whole or the winding end is heated to obtain a tubular laminate. The heating temperature is the glass transition temperature (Tg) of the decomposable resin + 10 ° C. or higher and the melting point (Tm) of the decomposable resin −5 ° C. or lower, preferably Tg + 15 ° C. or higher and Tm−15 ° C. or lower, more preferably Tg + 20 ° C. The temperature is preferably Tm−25 ° C. or lower. In general, the decomposable resin is excellent in adhesiveness with the tubular body base material, so that it is not necessary to use an adhesive or the like. However, when particularly necessary, the melting point is higher than the melting point (Tm) of the decomposable resin. Is heated between a melting point of the other resin and a temperature lower than the melting point (Tm) of the decomposable resin by interposing another resin having a low temperature between the stretchable resin stretched film and the tubular base material. Also good.

(3) A method for producing a tubular laminate comprising winding a long fiber yarn formed from a degradable resin around the outer surface of a tubular base material having a through hole in a tube wall. Degradable resin long fibers described above Including winding a yarn, that is, a monofilament yarn or a multifilament yarn around the outer surface of a tubular body substrate having a through-hole in a tube wall, thereby providing a decomposable resin molded product layer on the outer surface of the tubular body substrate. This is a method for producing a tubular laminate. The decomposable resin long fiber yarn is spirally wound around the outer surface of the tubular base material to form one layer formed from the decomposable resin long fiber yarn, and the angle with respect to the axis of the tubular base material is the same. Or by changing the length of the decomposable resin long fiber yarn spirally around the outer surface of the tubular body base material to form another layer formed from the degradable resin long fiber yarn. The process of forming a layer formed from the long resin filament yarn is repeated until a decomposable resin molded product layer having a predetermined thickness is obtained. A tubular laminate obtained by laminating resin molded product layers can be obtained. When winding the degradable resin long fiber yarn, it is preferable to wind the degradable resin long fiber yarn while applying a constant tension. Next, while applying pressure from the outside as necessary, the entire tubular base material around which the degradable resin long fiber yarn is wound or the end of the winding is heated to obtain a tubular laminate. The heating temperature is the same as that in the case of manufacturing a tubular laminate by winding a degradable resin stretched film around the outer surface of a tubular substrate having a through hole in the tube wall.

  When the tubular laminate of the present invention comprises two or more decomposable resin molded product layers, the methods described in (1) to (3) and methods according to them are repeated as necessary. Just do it.

  EXAMPLES Hereinafter, the present invention will be further described with reference to examples. However, the present invention is not limited to the examples. The measuring method of the physical property or characteristic of the decomposable resin or the tubular laminate in the examples and comparative examples is as follows.

[Average molecular weight]
The average molecular weight (Mw) of the degradable resin was determined using a GPC analyzer. Specifically, 10 mg of a degradable resin sample was dissolved in hexafluoroisopropanol (HFIP) in which sodium trifluoroacetate was dissolved at a concentration of 5 mM to make 10 mL, and then filtered through a membrane filter to obtain a sample solution. Then, 10 μL of this sample solution was injected into the GPC analyzer, and the weight average molecular weight calculated from the result obtained by measuring the molecular weight under the following measurement conditions was defined as the average molecular weight (Mw).

<GPC measurement conditions>
Apparatus: Showa Denko GPC104
Column: Showa Denko HFIP-806M 2 (in series connection) + Precolumn: HFIP-LG 1 Column temperature: 40 ° C
Eluent: HFIP solution in which sodium trifluoroacetate is dissolved at a concentration of 5 mM Detector: Differential refractometer Molecular weight calibration: Prepared using 5 types of polymethyl methacrylate (manufactured by Polymer laboratories Ltd.) with different molecular weights Using the calibration curve data of the measured molecular weight

[Melting point (Tm) and glass transition temperature (Tg)]
The melting point (Tm) of the degradable resin was determined in a nitrogen atmosphere using a differential scanning calorimeter (DSC; DSC-60 manufactured by Shimadzu Corporation). Specifically, the sample of the decomposable resin is subjected to crystal melting detected in a temperature rising process in which the sample is heated from room temperature to a temperature near melting point (Tm) + 60 ° C. at a temperature rising rate of 20 ° C./min in a nitrogen atmosphere. The melting point (Tm) is detected from the temperature of the accompanying endothermic peak, and the glass transition from the starting temperature of the secondary transition of the calorific value in the secondary transition region corresponding to the transition region from the glass state to the rubber state detected in the temperature rising process. The temperature (Tg) was detected. When a plurality of melting points (Tm) were observed, the temperature of the peak having the largest endothermic peak area was defined as the melting point (Tm).

[Hot water shrinkage (temperature 90 ° C-after 10 seconds)]
The hot water shrinkage rate of the heat shrinkable film was determined by the following method. That is, five sample films are cut out from one decomposable resin heat-shrinkable film, and the distance is 10 cm in the longitudinal direction (machine direction, MD) and lateral direction (direction perpendicular to the machine direction, TD) of each sample film. Mark at intervals. The sample film was immersed in water adjusted to a temperature of 90 ° C. for 10 seconds, then taken out, immediately cooled with normal temperature water, the marked distance was measured, and the shrinkage of the distance between the marks reduced from 10 cm The percentage of the previous distance (10 cm) is displayed as a percentage. About the five decomposable resin heat-shrinkable films, the average values in the longitudinal direction and the transverse direction were determined and displayed as “hot water shrinkage (temperature 90 ° C.−10 seconds later)”.

[Thickness of film]
The thickness of the film was determined by measuring the thickness at 10 locations of the sample using a micrometer [μ-mate (registered trademark), manufactured by Sony Magnescale Co., Ltd.], and obtaining the average value.

[Fineness]
The fineness of the long fiber yarn was measured according to JIS L1013.

[Weight reduction rate in hot water]
The method for measuring the weight loss rate after 1 week in water having a temperature of 90 ° C. in the tubular laminate (weight reduction rate in hot water) was as follows. That is, a tubular laminate sample cut to a length of 20 cm was preliminarily conditioned at a temperature of 23 ° C. and a relative humidity of 65% for 24 hours, and the weight of the untreated tube laminate was measured to obtain a tubular substrate (length 20 cm). The value obtained by subtracting the weight of) was defined as the weight of the decomposable resin molded product layer before treatment (referred to as “degradable resin weight before treatment”). Next, after immersing in distilled water maintained at a temperature of 90 ° C. for 1 week, the humidity was adjusted for 24 hours at a temperature of 23 ° C. and a relative humidity of 65%, and the weight of the tubular laminate was measured. The value obtained by subtracting is taken as the weight of the decomposable resin molded product layer after treatment (referred to as “degradable resin weight after treatment”). The weight reduction rate (%) in hot water was calculated as the ratio of the change in weight (decrease weight) of the degradable resin molded product layer before and after treatment to the weight of degradable resin before treatment.

[Biodegradability]
The biodegradability of the degradable resin molded product layer in the tubular laminate was determined by burying a sample of the tubular laminate cut to a length of 20 cm in soil adjusted to a temperature of 60 ° C., and the amount of carbon dioxide generated after 3 months. From this, the biodegradability was evaluated.

[Example 1]
PGA (manufactured by Kureha Co., Ltd., average molecular weight (Mw): 200,000, melting point (Tm): 220 ° C., glass transition temperature (Tg): 43 ° C.) Pellets were extruded at a temperature of 240 ° C. using an extruder equipped with a T die. An unstretched film having a thickness of 200 μm obtained by melt extrusion at a temperature of 55 ° C. is sequentially biaxially stretched 1.4 times in length and 1.4 times in width to obtain a PGA heat shrinkable film [hot water shrinkage ( Temperature 90 ° C. after 10 seconds): 30% / 30% (MD / TD), thickness: 100 μm].

  10 sheets of the heat-shrinkable film cut out to the size of 78cm in length and 62cm in width from the manufactured PGA heat-shrinkable film (thickness: 1mm) are 15cm in outer diameter and 60cm in length. After winding around the outer surface of a stainless steel cylindrical mesh body having an open 40 mesh mesh, it is heated in an oven at a temperature of 100 ° C. for 5 minutes to shrink the heat-shrinkable film, and the PGA heat-shrinkable film is made into a cylinder. A tubular laminate was prepared by laminating on the outer surface of the mesh body. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measurement of biodegradability, 90% of the PGA film was decomposed and collapsed when touched by hand.

[Example 2]
PLA (manufactured by Nature Works, average molecular weight (Mw): 260,000, melting point (Tm): 153 ° C., glass transition temperature (Tg): 67 ° C.) pellets using an extruder equipped with a T die at a temperature of 195 ° C. A 200 μm-thick unstretched film obtained by melt-extrusion at a temperature of 70 ° C. is sequentially biaxially stretched 1.4 times in length and 1.4 times in width to obtain a PLA heat shrinkable film [hot water shrinkage ( Temperature 90 ° C. after 10 seconds): 30% / 30% (MD / TD), thickness: 100 μm].

  Ten sheets of the heat-shrinkable film cut into a size of 78 cm in length and 62 cm in width from the produced PLA heat-shrinkable film (thickness 1 mm) are wrapped around the outer surface of the stainless steel cylindrical mesh body. After that, it was heated in an oven at a temperature of 95 ° C. for 5 minutes to shrink the heat-shrinkable film, thereby obtaining a tubular laminate comprising a PLA heat-shrinkable film laminated on the outer surface of the tubular mesh body. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measuring biodegradability, 65% of the PLA film was decomposed and collapsed when touched by hand.

[Example 3]
A 180 μm thick film obtained by melt-extruding the PGA pellets used in Example 1 at a temperature of 240 ° C. using an extruder equipped with a T-die at a temperature of 55 ° C., 3.0 times in length and 3.0 in width. After sequentially biaxially stretching twice, heat treatment (heat setting) was performed at a temperature of 120 ° C. for 30 seconds to obtain a PGA stretched film (thickness: 20 μm).

  Ten films cut into a size of 60 cm in length and 47 cm in width from the produced PGA stretched film were stacked (thickness: 200 μm) and wound around the outer surface of the stainless steel cylindrical mesh body. It heated for 5 minutes in oven, and obtained the tubular laminated body which laminated | stacked and integrated the PGA film on the outer surface of the cylindrical mesh body. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measuring biodegradability, 95% of the PGA film was decomposed and collapsed when touched by hand.

[Example 4]
A 180 μm-thick film obtained by melt-extruding the PLA pellets used in Example 2 at a temperature of 195 ° C. using an extruder equipped with a T-die, at a temperature of 70 ° C., 3.0 times in length and 3.0 in width. After sequentially biaxially stretching twice, heat treatment (heat setting) was performed at a temperature of 110 ° C. for 30 seconds to obtain a PLA stretched film (thickness: 20 μm).

  Ten films cut into a size of 60 cm in length and 47 cm in width from the produced PLA stretched film were stacked (thickness: 200 μm) and wound around the outer surface of the stainless steel cylindrical mesh body. It heated for 5 minutes in oven, and obtained the tubular laminated body which laminated | stacked and integrated the PLA film on the outer surface of the cylindrical mesh body. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measuring biodegradability, 70% of the PLA film was decomposed and collapsed when touched by hand.

[Example 5]
A PGA drawn multifilament yarn (fineness: 70 denier, number of filament yarns: 28, draw ratio: 4.5 times) obtained by melt spinning the PGA pellets used in Example 1 was made of the above-mentioned stainless steel cylindrical mesh After winding the wound yarn on the outer surface of the body until the thickness of the wound yarn reaches 10 mm, it is heated in an oven at a temperature of 100 ° C. for 5 minutes to laminate a layer of PGA multifilament yarn on the outer surface of the cylindrical mesh body. A tubular laminate was obtained. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measuring biodegradability, 85% of the PGA multifilament yarn was decomposed and collapsed when touched by hand.

[Example 6]
A PLA drawn multifilament yarn (fineness: 70 denier, number of filament yarns: 28, draw ratio: 4.5 times) obtained by melt spinning the PLA pellets used in Example 2 was made of the aforementioned stainless steel cylindrical mesh. After winding the wound yarn on the outer surface of the body until the thickness of the wound yarn becomes 10 mm, it is heated in an oven at a temperature of 95 ° C. for 5 minutes to laminate a PLA multifilament yarn layer on the outer surface of the cylindrical mesh body. A tubular laminate was obtained. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measuring biodegradability, 60% of the PLA multifilament yarn was decomposed and collapsed when touched by hand.

[Comparative Example 1]
Heat-shrinkable polyethylene terephthalate (hereinafter referred to as “PET”) film [molecular weight (Mw): 20,000, thickness: 100 μm, hot water shrinkage (temperature 90 ° C.—after 10 seconds): 30% / 30% (MD / TD), 10 sheets of heat-shrinkable film cut into a size of 78 cm in length and 62 cm in width from CB602S manufactured by Far East Boshoku Co., Ltd. (thickness 1 mm), and in the same manner as in Example 1, After being wound around the outer surface of the cylindrical mesh body, it is heated in an oven at a temperature of 100 ° C. for 5 minutes to shrink the heat-shrinkable film, and the heat-shrinkable film formed from PET is used as the outer surface of the cylindrical mesh body. To obtain a tubular laminate. Table 1 shows the measurement results of the weight loss rate in hot water for the obtained tubular laminate. As a result of measuring biodegradability, the PET film was not decomposed at all.

  From the results in Table 1, a layer made of a molded product formed from PGA or PLA, which is a degradable resin that is decomposable in an aqueous solvent, is laminated on the outer surface of a tubular body substrate having a through hole in the tube wall. It was found that the tubular laminates of Examples 1 to 6 can completely or efficiently decompose and remove the resin layer blocking the through holes in an aqueous solvent. Moreover, it turns out that the tubular laminated body of Examples 1-6 is biodegraded in the ground in a short period of 3 months, and is suitable especially for uses, such as well excavation which embeds a tubular laminated body in the ground. It was guessed that it was. Furthermore, it was speculated that the degradability (weight reduction rate in hot water) and biodegradability in an aqueous solvent can be controlled by selecting a degradable resin or a molded product formed from the degradable resin.

  On the other hand, the layer of Comparative Example 1 formed by laminating a layer formed of PET, which is not a degradable resin having degradability in an aqueous solvent, on the outer surface of a tubular body substrate having a through hole in the tube wall. It has been found that the tubular laminate cannot decompose or remove the resin (PET) layer blocking the through hole in an aqueous solvent and biodegrade in the ground.

  The present invention provides an outer surface of a tubular substrate having a through-hole in a tube wall of a layer made of a degradable resin that is degradable in an aqueous solvent, preferably a biodegradable aliphatic polyester resin. In the tubular laminate having a through hole on the tube wall, the through hole can be reliably closed and reliably opened as necessary. In particular, no special operation is required for opening, the number of processes is reduced, and after opening the through hole, the through hole is closed or the material used for opening is discarded. Since the substances that become waste do not affect the environment, it is possible to provide tubular articles that are unnecessary or easy to process. Can be used industrially due to its small size High sex.

  In addition, the present invention provides a tube having a through-hole in a tube wall of a heat shrink film formed from the decomposable resin, a stretched film formed from the decomposable resin, or a long fiber yarn formed from the decomposable resin. Since the manufacturing method of the tubular laminated body which can obtain the said tubular laminated body easily by including winding on the outer surface of a body base material is provided, industrial applicability is high.

Claims (12)

A layer of a molded article formed from a biodegradable resin having a degradable in an aqueous solvent, Ri Na laminated on the outer surface of the tubular base body having a through hole in the tube wall,
The layer includes at least one layer and the total thickness of the layer is in the range of 1 μm to 3 mm.
A tubular laminate in which the layer has a weight loss rate of 50% or more after being immersed in water at a temperature of 90 ° C. for 1 week .   The tubular laminate according to claim 1, wherein the degradable resin is a biodegradable resin.   The tubular laminate according to claim 1 or 2, wherein the degradable resin is a biodegradable polyester.   The tubular laminate according to claim 3, wherein the biodegradable polyester is a biodegradable aliphatic polyester.   The tubular laminate according to claim 4, wherein the biodegradable aliphatic polyester is at least one selected from the group consisting of polyglycolic acid, polylactic acid, glycolic acid-lactic acid copolymer, and mixtures thereof. The tubular laminate according to any one of claims 1 to 5 , wherein the molded product is a film or a textile product. The tubular laminate according to claim 6 , wherein the film is at least one selected from the group consisting of an unstretched film, a stretched film, and a heat-shrinkable film. The tubular laminate according to claim 6 , wherein the fiber product is at least one selected from the group consisting of a nonwoven fabric, a woven fabric, a knitted fabric, and a long fiber yarn. The tubular laminated body according to any one of claims 1 to 8 , wherein the tubular body base material having a through hole in the tube wall is a tubular body for a well drilling device. The heat-shrinkable film formed from the decomposable resin is wrapped around the outer surface of a tubular base material having a through hole in the tube wall, and then heated to a temperature equal to or higher than the heat-shrink temperature of the heat-shrinkable film. The method for producing a tubular laminate according to any one of claims 1 to 9 , comprising heat-shrinking the shrinkable film to form a heat-shrinkable film. The tubular laminate according to any one of claims 1 to 9 , comprising winding the stretched film formed from the degradable resin around an outer surface of a tubular substrate having a through hole in a tube wall. how to. The tubular laminate according to any one of claims 1 to 9 , comprising winding the long fiber yarn formed from the degradable resin around an outer surface of a tubular substrate having a through hole in a tube wall. How to manufacture.