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`Polyglycolic acid resin particulate composition
`for boring, and method for producing same
`W0 2912321284 £1
`
`ABS'i‘RA (‘1‘
`
`Provided is a polygiycollc acid resm particulate composition that is for boring
`and that is formed by adding 0 01~15 masses of an antibtockirig agent. which
`preferably is dissolved or broken, down in a liquid carrier for every 100 masses
`of a pctyglycolic acid resin particulate having an average. particle size of 0.01.
`1000 um Preferably, the vertical breaking stress {Ft} of a cylindrical tablet
`formed from the particulate composition under the forming conditions of 3
`temperature that as at ieast the glass tranSition temperature of the polygiycolic
`
`Publication number
`Publication type
`Application number
`Publication date
`‘
`Filing date
`Priority date
`Inventors
`'
`Applicant
`Eme't Citation
`
`Patent Litafions
`Legs. Events ;- ,4
`
`
`
`wozommm A1
`Application
`P T:JP2012/055l338
`Sep13, 2012
`Mar 7, 2012
`Mar 8, 2011
`
`Ma 'ahiro Vamezaki. 9 More >r
`'-"“‘ ”42‘in .ii‘i’.
`
`mm”? "r (W m on X:
`BiBieX Endi‘soie. Refit/tan
`i at
`r“.
`Referenced by ~' ‘v; ma.
`
`ions 55.».
`
`External Links: Patentscone. Esiiacenet
`
`
`acid resin minus 5‘”: and a load of 100 gticmz that is loaded for 2:; hours is no greater than 1000 gifcmlj and/"or formuia F1IFO. which comprises F1. and the
`
`breaking stress (F0) of a cyiindrlwl tablet formed from the particuiate at the aforementioned forming conditions, is no greater than 0.95, Further
`‘ *v‘ided its a
`method for producmg the particulate composition
`
`DESCRIPTION nan; (‘I...U\'ES
`
`Wei: drilling for polyglycolic acid resin particulate composition and a ma.
`manufacturing the same
`
`1. Average particle diameter to pdlyglycoiic acid resin granules 100 parts by
`weight is 001 ~ 1000 ,mum, antiblocking agents polyglycoiic acid resin
`particulate composrtion for wells drilled obtained by adding 0.01 to 15
`.
`parts by weight
`
`i
`l
`i
`15"»
`.
`Thr
`e p esert invention has an excel ert anti block ng effect, pclyglyco ic ac d
`FEE-it". granuiate composition for weii drilimg comprising poiyglycclic acid resrn
`granules. and a method of manufacturing the same.
`
`Polyglycolic acid resin (hereinafter sometimes referred to as "PGA'ii And the
`poiylactic add resin {hereinafter sometimes referred to as ”PLA“.) The aliphatic
`polyester resin or the like, microorganisms present :ri nature such as soil or sea
`or to be decomposed by an enzyme, has been attracting attention as
`biodegradable poiymeric material load is small with respect to the environment.
`These biodegradable aliphatic poiyester resins, because they have a
`biodegradable and bioabsorbable, is also utilized as a medical polymer
`material, such as surgical sutures. artificsal skin
`
`The biodegradable aliphatic polyester resins, PLA consisting of iactic acid
`repeating units, PGA consisting giyoouc acid repeating units, iactone polyester
`resms such as poly c- caproiactone, polyhydroxybutyrate poiyester resins, and
`these do polymers, for example. copolymers of gl)'coi:c acid repeating units and
`lactic and repeating unit {hereinafter sometimes referred to as “PGLA” l and the
`like are known.
`
`Among the biodegradable aliphatic polyester restr, PGA, an addition to the high
`degradation reSistanoe, heat resistance, mechanical properties such as tensiie
`strength, and aiso exceilent gas barrier properties when formed into a particular
`film or sheet Therefore. PGA is agricultural materials, use as various packaging
`
`{container} materials and medical polymer materiaf is expected, either alone or
`
`'3:
`
`('4!
`
`4,.
`
`‘
`
`in such a appiication deployment compiexed other resin materials is achieved
`
`As a method for producing a product from the PGA, extrusion molding
`molding. compressor: molding, injection compression molding, transfer
`molding, cast molding, stampable molding, blow molding, stretched tiim
`
`35?
`
`.,
`
`m;
`other molding methods melt moiding is employed. Peiiets PGA used as a
`Womfiwgttsfimanmim mmmmswmwgrammmm and Japanese and Son
`
`molding. inflation film molding laminate molding, calender molding, foam moi-ding. RlM molding, FRP molding. such as powder molding or paste molding,
`
`
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`Patent W02012121294A1 - Polyglycolic acid resin particulate composition for boring, an... Page 2 of 17
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`the PGA melt into strands extruded usrrig a twin-screw extruder, the average
`particle size obtained by cutting into a predetermined size There are of size of
`about several mm. The powder PGA used as a molding material for powder
`molding or paste forming a predetermined srze and PGA granules prepared in
`
`shape :s used depending on the application.
`
`Additionally PGA granulate. degradable F’GA, by focusrng the like in heat
`resrstance and mechanical properties, paints. coatings. inks. toners.
`
`agrochemicals, pharmaceuticals. cosmetics.
`ng. raw material in areas such
`as well drining or use as such additives have been expected The PGA granules to be applied to these areas. the particle
`diameter that matches the object. granules having a particle properties such as particle size distribution and particle shape
`are obtained.
`
`
`
`of natural gas and hot springs and the like. the bit attached to the drill tip.
`For example. petroleum, :n well drilling for mi;
`
`take the welibore while crushing the rock formations while rot
`'irlr; carry away the shattered rocks on the ground. in well
`drilling the reduction of friction between the drill and Anakabe. bit cooling. unloading. etc. were shattered rocks. the
`purpose of the collapse preventing Anakabe formed by excavation. bentonite. mica, hydrated lime. carboxy
`methylceliulose. particulate material such as a Silicone ream. a slurry of drilling dispersion obtained by dispersmg in a liquid
`carrier such as water or an organic solvent =.‘ "hereinafter. sometimes referred to as" welibore fluids " ,i it is used ij Patent
`documents 1 and 2}, Drilling dispersrons. the granulate. water or ethylene glycol. propylene glycol. glycerol. diols or triois
`
`
`:il or tr: acrd glyceryl poiyglymis
`such as t-‘imethylene glycol, glyceryl tnacetate (triacetini. Toripuroplon glyceryi (trlpr .~
`such as polyethylene glycol; glycerol esters such as (tributyrinl a liquid carrier selected from an organic solvent such as,
`
`lost circulation preventing agent a s
`:fic gravrty agents, dispersing agents. surfactants, viscosity modifiers. thickeners.
`etc. dispersed with additives. and is used. The particulate material used in the drilling for dlspersron. for allowrng
`excavation wort-r. fluidity. heat resistance. chemical stab:lity. while at the same time have mechanical properties other
`properties, dr..i.ng quickly during excavation work completed dispersion be discharged. and it is necessary to be safely
`disposed of. granulate composition and particle properties satisfying these requirements has been demanded.
`
`PGA granuiate. fluidity. with has the properties that do not interfere with the neat resrstance and other drilling operations,
`biodegradable. since disposal from having a hydrolyzable becomes sample, the drilling dispersion the Lise of :l is expected.
`Accordingly, in such granuiate composition and particle characteristics, well dr:lllng for PGA granulate compositions
`containing an optimum PGA granules to drilling disperSion is demanded
`
`Further. as the PGA granules. excellent granulate handling properties and storage stab:lity are desited For example.
`granulate sma=l particle size. as well as handling properties become poor. hygroscopicny increases. also there the surface
`area is increased. the influence of the degradatior rate increases. excellent characteristics of the PGA is lowered with
`
`which may put away. it fears that trouble unexpected in the drying step and molding occurs was not nil
`
`Method of manufacturing a biodegradable aliphatic polyester resrn granules such as PGA and PLA have been proposed
`
`For example, a manufacturing method of the granules by the cutting or grinding of melt solidified product. the production
`" or dispersion is know}:
`method of the granules by precipitation from a soluti
`Patent Document 3,. a chip or lumps
`
`consisting FLA resin. and cooled to a low temperatue 0t -50 ~ 480 “ (2,. preparation of poiylactic acid-based resin powder
`to impact crushed classification is disclosed. Patent Document 4. a biodegradable aliphatic polyester resin of the organic
`solvent solution and aromatic hydrocarbons and mixed at a temperature below 60 “ C . sclld~liquid separation of solid
`product precipitated. biodegradable method for producing a powdery polyester resin haying is disclosed. in the examples.
`Mwl4,5 thousands of PLA. th 0.0 thousands of polybutylene succinate. and Mwl?’ 2 thousands of copoiyrnerization of
`PLA and polybutyiene succinate coalescence is used as a raw material. Patent Document 5. Production Example 3. using
`a Pl}. the solvent ~." methyl adlpate. dimethyl gluterate. a mixture of dimethyl succrnate (DBE (r
`tered trademark}
`
`
`manufactured by Du Ponti). arid the dissolution temperature of 140 ° C . an average primary particle orarreter of 250nm or
`less of the PLA granulate the cooling temperature was obtained as -35 “ C.. or by using as the production example 4. and
`PGA, solvent this ijzwmethoxyethylf; ether). dissowed temperature 0.99 " -::Z.. an average primary particle diameter of the
`coolmg temperature was obtained as —35 " C are disclosed the following PGA granules 150 nm.
`
`However while PGA granules. even to obtain a granulate having a particle characteristics suitable for applauazlon. then
`until use granular bodies on the appliwtion of the product. such as described above, which is carried out storage and
`transportation. granular body had to aggregate (blocking) When blocking granules occurs. along with the handling of the
`granulate is deteriorated, the average particle size of the granules produced are controlled to sort the application. the
`
`
`particle size distrii
`iron. shape and the like as lost, desired charaztc
`as it may no longer be able to exert. Once the
`blocking granules occurs. even applying mechanical stimulus such as vibration. easily is sometimes persists aggregation
`state of the granules. addition. in order to obtain a dotting dispersions. water or an organic be dispersed in a liquid carrier
`such as a solvent. the desired average particle size. there may not be able to recover the particle size distribution and
`shape. in particular. PGA granuies. the glass transition temperature at (T9 about 40 “ C.) under near above temperature
`env=ronment. when the load is applied. blocking is likely to occur, For example. in the storage and transportation of the
`granules in the summer and containers. because it may granules is exposed to "lg near or above the high temperature. the
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`Patent W02012121294A1 - Polyglycolic acid resin particulate composition for boring, an... Page 3 of 17
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`Therefore. changes or the storage method of the granulate (cold storage. or the like for stacking flat). contains an anti--
`blocking agent but measures or to (Patent Document 6) are have been taken, change of storage method is cost lead to
`
`aiso slmpiy mixing antiblocKing agents, that the anti-blocking agent. which may or adversely impact on the
`,.etion
`cr wel: drilling operations after the end of discharge or disposal of wet! drilling operations agenda is produced, it has been
`a demand for further improvement.
`
`JP 2000-282020 JP Kohyo 2005-534746 JP (US. Patent Application Publication No 200610111521 corresponding) JP
`2001-288273 JP JP-t1—35693 discloses JP 2006415542 JP JP 20031113344 JP
`
`An object of the present invention. welE driinng for PGA granulate composition having excellent antr— locking effect. and to
`prevrde a manufacturing method thereof.
`
`The present inventors have found that in order to solve the above problems. among which intensive continue parsing
`
`phenomena biocking PGA granules occurs. in particuiar. PGA granules obtained by the so-catied :
`zct milling method at
`the time of pulverization the shearing force, the surface of the granules has been found that the ratio of the melt softened
`amorphous portion is large. The object or‘ the result of further studying the modification of the surface of the particulate
`material. by the PGA granular composition with the addriion of antiblockrng agents to the PGA granulate. well dnliing for
`PGA particulate composition it found that can solve, and have completed the present invention.
`
`That is, according to the present invention. the average particle size to PGA granules 100 parts by weight is 0.01 ~
`1000 mum. antibiocking agents PGA granulate for welis drilled obtained by adding «‘3- 01 to 15 parts by weight composition
`is provided.
`
`Further, according to the present invention. as an aspect of the embodiment, the foilowing (1} to well drilling for PGA
`granulate composition (4) :s provided,
`
`{1) F1' the particulate composition. a glass transition temperature of-5 ° C. or more temperatures PGA. vertical fracture
`
`stress of cyEiridrical tablets motded‘ in molding conditions of a load of 1.00 gt 3' cm 2 24 hours. the formula) F1 g 100ng r em
`
`I“ the weiibore drilling PGA granulate composition satisfywrg
`
`(2)- the F1, and Po. the granulate, vertical fracture stress of cylindrical tablets molded in molding conditions above; is ofthe
`formula) Ft .:' F0 said welibore driiling PGA particulate satisfying 5- 095 body composition,
`
`{3) anti~blocking agent is an inorganic substance or the wellbore dnliing PGA particulate composition iS an organic
`material.
`
`(4) antl‘blocking agent. decomposition or the weiibore drilling PGA mdicuiate composition is a substance that dissolves to
`a iiqu:d carrier of the drilling dispersion.
`
`Furthermore. according to the present invention. the average relative ti-eitittte size of PGA granules 100 parts by weight is
`001. ~ 1000 mum. the anti-blocking agent was added in an amount of 0.01 to 15 parts by mass. the glass transition
`temperature of 0 "-ii’ or PGA at a temperature ranging from «5 “ C. or less. the production method of the welibore dn‘iiing
`PGA granulate composition mixed and stirred 5 minutes to 2 hours is provided
`
`According to the present invention, the average particle size to PGA granules 100 parts by weight is 0 01 ~ 1000 .rnu.rn.
`antibiockrng agents PGA granulate composition forweils dnlled obtained by adding 0.01 to 15 parts by weight by it,
`blocking hardly occurs even by storage or transport. also has the effect of well drilling for PGA granules are obtained
`betting the required particle characteristics to eliminate the very easily blocking even once blocking occurs it is so.
`
`Further. according to the present invention. the average relative particle size of PGA grannies 100 parts by weight is 001
`~ 1.000 mum. the anti—blocking agent was added “h an amount of 0.01 to 15 parts by mass, the glass transition
`
`
`to 2 hours. the
`temperature of O “C or PGA at a temperature ranging from -5 “ C. or less, by :n'
`’ g and stirring 5 iii-i:
`effect is achieved that the weilbore drilling PGA particulate composition can be essay produced.
`
`1 PGA constituting the weilbore drilling PGA graniitate composition of the pdlyglycoiic acid resin present invention has the
`formula, t~ O-~CH 2 -C (0} _) consisting only of giycoiic acid recurring unit represented by the giycolic acid in addition to the
`homopolymers {including ring—opening polymerization of glyootide is 2 intermolecular cyclic ester of glycotic acad). the
`glycolic acid repeating urine meant to include PGA copolymers containing more than 50 wt‘l-iy. PGA can be synthesized by
`dehydration polycondensation of glycotic acad which is a- hydroxy carboxylic acids. To synthesize efficiently high molecular
`weight PGA is the ring-opening polymerization of glycolide are used a bimolecuiar cyciic ester of glycolic aCid
`
`With giyreiu; acrd monomers such as the glycoiide. as a comonomer to provade a PGA copoiyrners e g., ethylene oxalate,
`lactide. lactones, carbonates. ethers. cyclic monomers such as ethers esters and amides; :actic acid. and ethylene glycol.
`aliphatic diols such as 1V4‘butanediol. 3-hydroxyprcpanoic acid 3-hydroxybutanoic acid. 4-hydroxybutanoic acid,
`6~hydroxy carboxylic acrd or its alkyt esters such as hydroxy caproic acrd succmic acrd. substantially equimolar mixture of
`an Siphatic dioarboxyiic acid or its alkyi esters such as adipic acid. or can include two or more of these These
`
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`12/6/2017
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`Patent W02012121294A1 - Polyglycolic acid resin particulate composition for boring, an... Page 4 of 17
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`material for providing PGA copclymer. Preferred conionorners are lactic acid. copolymers of glycolic acid and lactic acid
`lPGLA) is formed,
`
`The glycolic acid recurring unit in the PGA of the present invention is at least 50 wt%, preferably 70 wt% or more, more
`preferably 85 mass% or more, more preferably 95 wt% or more, particularly preferably 98 wt% or more There. most
`preferably substantially PGA honiopolymer is at least 99 mass"? . if the proportion of the repeating glycolate units is too
`small, degradable expected of PGA. heat resistance. strength and the like become poor. Repeating unit other than the
`
`repeat
`;4- glycolic acid units is 50% by weight or less, preferably 30 wt% or less. 15 wt% and more preferably less. more
`preferably 5 mass‘bl; or less. particularly preferably not more than 2 wt%. most preferably is used in a proportion of 1% by
`mass or less. it may be one mat does not comprise recurring units othe,r than recurring glycolic acid units,
`
`The PGA according to the present invention, to produce the desired high molecular weight polymer efficiently. PGA
`obtained by polymerizing glycoiide 50—100 wt% and 50-0 wt'l‘s other comonomers described above are preferred, Other
`comcnomers may be a cyclic monomer between two molecules. may also be a mixture of both. not cyclic monomer for the
`present invention to the PGA granulate of interest. cyclic monomer it is preferred. it will be described in detail below PGA
`obtained by ring—opening polymerization of glymlide 50-100 wt% and 50-0 wit/c another cyclic monomer.
`
`{Glycolide}
`
`.i is 2 intermolecular cyclic ester of glycolic acid Method for
`Glycoilde to form the PGA by ring-opening polymens
`producing glycolide is not particularly iamited. in general. the glycolic acid oligomer may be obtained by some thermal
`polymerization As depolymerization of gl 'colic acid oltgomer. for example. the melt depolymerization process. solid-phase
`dopolymerizaiion process. can be employed as a solution depolymerization process. also be used glycolide obtained as
`cyclic condensates of chioroacetic acid salts can. incidentally. if dessred. as a glycolide. a limit of 20°11; by weight of the
`glycclide content. it is possible to use those containing glycolic acid.
`
`
`
`,
`ion of glycolide alone, or may be formed
`PGA in the present invention may be formed by ring—opening r:
`siinuitaneously opening polymerization was a copolymer with other cyclic monomers as a copolymer component. When
`forming the copolymer. the proportion of glycollde. at least 50 wt%. preferably 70 wt% or more. more preferably 85 mass%
`or more. more preferably 95 wt% or more. particularly preferably 98 mass not less than%. and most preferably
`substantially PGA homopoiymer is at least 99 mass%
`
`{Other cyclic monomer}
`
`Other cyclic monomers that can be used as a copolyrnerization component of glycolide. outside the intermolecular cyclic
`esters of other hydroxycarboxyiic acids. such as lactide. lactones le.g.. beta-propiolactone, beta-butyrolactone.
`pivalolactone, gamma.--butyrolactone, delta—valerolactone. beta-methyl or valerolactone. .epsilonxcaprolactone).
`trimethylene .sr‘iotr can be used cyclic monomers such as 1.3-dioxane. Other preferred cyclic monomers is 2
`intermolecular cyclic ester of other hydroxy carboxylsc acids. the hydroxycarboxyllc acids. for example, L- lactic acid, D-
`lactic acrd. alpha-hydroxybutync acrd. alpha-hydroxy isobutyric acid. alpha- hydroxyvalerlc acid. alpha-hydroxycaproic
`acid, alpha-hydroxyisocaproic acid. alpha-hydroxy heptanoic acid. alpha~hydroxy octanoic acid , alpha-hydroxy decancic
`actd. alpha-hydroxy myristic acid, alpha-hydrant stearlc acid. and their and the like alel substituents. Particularly preferred
`other cyclic monomer is lactide is 2 intermolecular cyclic ester of lactic acid. L form. D. racemates, may be any of these
`mixtures
`
`Gther cyclic monomer is 50 mass% or less. preferably 30 wt% or less. 15 wt% and more preferably less. more preferably 5
`mass% or less. particularly preferably not more than 2 Wt‘i’o, most preferably from ‘: wt% used in the following proportions.
`PGA is. if formed from glycolide 100 wt%, the other cyclic monomer is 0 mass%. the PGA is also included in the scope of
`
`the present invention By polymerizing ring~opening copolymeri
`on of glycolide and other cyclic monomer lowermg the
`processing temperature by lowering the melting point of the PGA copolyrner {crystalline melting pOint). extrusion
`processabiisty and stretchability to control the crystallization rate it is possible to improve However. when the proportion of
`these cyclic monomers is too large. crystallinity of the PGA cooolymer formed is impaired. such as heat resistance and
`mechanical properties deteriorate
`
`{Ring-openlng polymerization reaction}
`Ring-opening polymerization or ring-opening copolymerization of glycollde (hereinafter, collectively. may be referred to as
`"ring-opening {co} polymerization" } it is preferably carried out in the presence of a small amount of catalyst. The catalyst is
`
`not particularly
`3‘, for example, tin halides {e 4 , tin tetrachloride, tin chloride) and organic tin carboxylates leg.
`2-octoate. such ethylnexanoate) tin ternpounds such as . alkoxy titanium compounds such as alkoxy titanate; aluminum-
`based compounds such as alkoxy aluminum; zirconium compounds such as zirconium acetylacetone: antimony halides,
`antimony compounds such as antimony oxide; and the like The amount of the catalyst used. the cyclic ester. at a mass
`ratio, preferably 1 ~ 1000 ppm. more preferably about 3 ~ 300 ppm
`
`Ring~opening loo)- polymerlzatlon of glycolio‘e. in order to control the physical properties such as melt viscosity and
`molecular weight of the resulting PGA. as alcohol and the molecular weight modifier protlc compounds such as water.
`such as lauryl alcohol higher alcohol it can be used. Normally the glycolide may the small amount of moisture.
`hydroxycarboxylic acro compounds consisting of glycolic acid and linear giycolic acid oligomers are contained as
`”fry the new Soogle Fatsnta. with machinavclasslfied Georgie Scholar results. and Japanese and South Korean patents.
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`https Lil/encryptedgoogle.com/patcnts/WO20l 2121294A1 ?cl=en
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`Patent.W02012121294A1 - Polyglycolic acid resin particulate composition for boring, an... Page 5 of 17
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`impurities, also these compounds act on the polymerization reaction Therefore, the concentration of these impurities for
`example, quantified as a molar concentration due neutralization titration of the carboxylic acids present in these
`
`compounds, also alcohols, water was added as a profile
`compound depending on the molecular weight of the object, all
`protons the molar concentration of sex compounds can be carried out adjustment of the molecular weight of produced
`PGA by controlling relative glycoiide. Further, for mproving physical properties, it may be added to polyhydric alcohols
`such as glycerin.
`
`on but. in many cases.
`Ping-opening (co) polymerization of glycoiide. even in bulk polymerization, or solution poly
`bulk polymerization is employed. The polymerization apparatus of bulk polymerization, an extruder—type, paddle blade and
`having a vertical. vertical type haying a helical ribbon blade, extruder type or kneader type horizontal. ampoule type. plate
`type, various such tubular mold from the device, it. can be appropriately selected. Further. the solution polymerization. it is
`
`possible to use
`s reactors
`
`
`
`The polymerization temperature can be set appropriately according to the object within the range of from 120 ° C is a
`substantial polymerization start temperature to 300 ° C.. The polymerization temperature is preferably lSO ~ 270 ° C..
`
`more preferably 140 ~ 260 ‘“ Q, part-“unarly preferably from 0.99 ~ 250 “ C.. if the polymerization temperature is too low. it
`tends to become wider molecular weight distribution of the produced PGA. if the polymerization temperature is too high,
`
`the resulting PGA is St.
`sale to thermal decomposition. The polymerization time is 3 minutes to 50 hours. preferably in
`the range of 5 minutes to 30 hours. And polyltterixatlon time is too short polymerization is sufficiently hard to proceed, it is
`
`impossible to achieve a given weightaverage molecular weight. PGA produced and the so
`\iion time
`too long
`tends to develop color
`
`After the resulting PGA to a solid state, optionally, it may be further subjected to solid phase polymerization The solid
`
`
`phase polymerization, by 5':
`. .. its at a temperature below the it
`rig point of PGA, means an operation of heat treatment
`while maintaining the solid state. The solid-phase polymerization. unreacted monomer, low molecular weight components
`such as cisgomers volatilized and removed. Solid state polymerization is preferably from i to 100 hours. more preferably 2
`to 50 hours, particularly preferably at 3—30 hours
`
`Further. the PGA in a solid state. its crystalline melting point (Tm). above, by providing a thermal history by step preferably
`of melt-kneading at a temperature ranging from the crystal melting pornt {Tm} up to the crystalline melting pornt (Tm) + 100
`“‘t‘. crystalline it may control the sex.
`
`[Weight average molecular weight ,wai}
`The weight average molecular weight of PGA contained in the wells drilled for PGA particulate composition of the present
`invention (Mw; of, preferably those in the range of 5 to 1.5 million and more preferably from 6 to 1,300,000, more
`preferably P1100000, particularly preferably selected that is within a range of 10 to 1,000,000. The weight average
`molecular weight of PGA (MW) are those determined by gel permeation chromatography (GPC) apparatus.
`
`[Crystalline melting point {Troll
`
`Crystalline melting point of the PGA in the present :nvention {Tm} is usually 1.97 ~ 245 ° C., can be adjusted by the weight
`average molecular weight (MW). molecular weight distribution, copolymerization component types and content, and the
`like PGA crystalline melting point of {Tm} is preferably 200 ~ 240 " C. more preferably 205 ~ 235 “ C.. particularly
`preferably 210 ~ 230 " C. Crystalline melting point of the homopolymer of PGA (Tm) is usually about 220 ° C When the
`crystal melting posnt {Tm} ls too low, heat resistance and strength or insufficient. When the crystal melting point (Tm) is too
`hgh. or insufficient workabilliy. can not be sufficiently control the formation of granulate, grain size of the PGA granules
`obtained may not become those of the desired range. PGA crystalline melting 110.“:th of (Tm), using a differential scanning
`calorimeter (080}. are extracted by a nitrogen atmosphere. Specifically. a sample PGA, heated to about 280 “ (3., was
`maintained for 2 minutes at this terriperature, the amorphous sample obtained by rapidly cooled (approximately 100 ° C. .-"
`mini by liquid nitrogen. a nitrogen atmosphere among means the temperature of the endothermic peak by crystal melting
`that is detected in the course of reheating at a heating rate of 20 " <1:
`i‘ min from approximately room temperature. When
`
`the endothermic peak is more observed, the largest peak is thee:
`.. peak area and the crystal melting point (Tm),
`
`{Glass transition temperature (T9; or,-
`Tne glass transition temperature of the PGA in the present invention (T9) of a customary 25 ~ 60 ‘ 0. preferably 30 ~ 55
`9‘.
`. more preferably 32 ~ 52 ’ C particularly preferably 35 ~ 50 “ 0,, The glass transition temperature of the PGA (Tg) can
`be adjusted by the weight average molecular weight {MW}, molecular weight distribution, copolymerization component
`types and content, and the like. The glass transition temperature of the PGA leg}. using a differential scanning calorimeter
`{-330}, are extracted by a nitrogen atmosphere. Specifically, a sample PGA. heated to about 280 ° C , was maintained for
`2 minutes at this temperature, the amorphous sample obtained by rapidly cooled (approximately 100 “ C, {min} by liquid
`nitrogen, differential scanning using calorimeter (.086), in a nitrogen atmosphere. at the time of revheatlng to 100 ” C. at a
`heating rate of 20 " C l min from approximately room temperature, a second order transition region corresponding to the
`transition region from the glass state to a rubber state heat the secondary transition start temperature and end
`temperature glass transition temperature midpoint of (T9) in. {hereinafter sometimes referred to as ”intermediate glass
`transition temperature" i to. When the glass transrtlon temperature (T9) is too low, such as by heat generated by the
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`Patent W02012121294A1 - Polyglycolic acid resin particulate composition for boring, an... Page 6 of 17
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`which may
`granules is likely to occur When the glass transition temperature (Tgl is too high decomposrtion of
`
`the actual use
` 5 Mt lent. the functions required may not be exhibited
`
`2 PGA granulate to form the average particle diameter of poiyglycolic acid resin granules borehole drilling PGA particulate
`composition of the present invention is 0.01 to t000 mum, the mean particle diameter (50% D) is 0 01 to a PGA
`granulate is 1000 .mu.m.
`
`
`furthei: if desired, in
`PGA granules in the present invention is a granular material for the above PGA composed it.
`addition to the PGA. to the extent not contrary to the object of the present invention, PLA and other biodegradable aliphatic
`polyester resrns. polygiycols such as polyethylene glycol, polypropylene glycol, modified polyvinyl alcohol. polyurethane. or
`other resins such as polyamides such as poly L- lysine. plasticizers. antioxrdants. terminal blocking agent, thermal
`stabilizer . light stabilizers. UV absorbers, lubricants. mold release agents, colorants, crystallization accelerators, hydrogen
`ion. concentration adjusting agent, antismtéq agent needs the usual additives to be blended, such as fillers, such as
`relnforcrng fibers or it may be formulated by such direct mixing of the melt blended or resin granules according The
`amount of such the additives, relative to PGA100 parts by weight. usually 30 parts by weight or less, preferably 20 parts by
`mass or less. and more preferably not more than it) parts by mass, 5 parts by weight or less, or 1 part by weight or less of
`the formulation when you are satisfied with the arriount in some cases
`
`[Average particle diameter {50% 0)]
`The average particle diameter of the PGA granules an the present invention (50% D) is the PGA granules, the granules
`dispersion dispersed in ion-exchanged water was determined and measured using a laser diffraction type particle size
`distribution measuring apparatus using the particle size distribution of granules. the cumulative mass from the small
`particles dick means a value expressed by the particle diameter at 50%.
`
`The average particle diameter of the PGA granules in the present invention (50% D; is preferably 0 1. ~ 800 {mu} m, more
`preferably 1 ~ 600 .rnumr more preferably 5 v 500 {mu} in. particularly preferably in the range of 10 ~ 400 {mu} in. When
`the average particle diameter (50% D; is too small, handling properties and storage stability of the granules is poor When
`the average particle diameter (50% U: is too large. in addition to such lost Circulation prevention capability during we:i
`drilling becomes insufficient, fear not preferable to cause a decrease in productivity fluid recovery efficiency by screen
`w.
`clogging By average pa.-
`
`* diameter (50% D) is within the range of 0.01 ~ 1000 mu m, with the fluidity of the PGA
`granules is good, a good handling property and storage stability of the granules, applied to the wellbore fluid when. it can
`be discharged drilling operations and subsequent welibore fluid we