 method in which a high-molecular weight PTFE powder or formed body is irradiated with an ionizing radiation (e.g., see Patent Document 3).
However, methods involving thermal degradation of high-molecular weight PTFE and methods involving the exposure of high-molecular weight PTFE to radiation are not always advantageous from the standpoint of equipment costs and convenience.
A process involving direct polymerization of the TFE monomer in the presence of a chain transfer agent is also known as a method for producing low-molecular weight PTFE. For example, Patent Document 4 proposes performing polymerization using a C1-3 fluoroalkane or chlorofluoroalkane as a chain transfer agent (telogen).
As in the case of the method of Patent Document 4, it is not always clear which process is to be used as the industrial polymerization method, but such industrial methods can be roughly divided into suspension polymerization and emulsion polymerization.
In suspension polymerization a polymerization initiator is dispersed in an aqueous medium in the presence of a chain transfer agent using little or no surfactant, TFE is polymerized either with TFE or a monomer copolymerizable therewith, and a low-molecular weight PTFE granular powder is directly isolated from the reaction (e.g., see Patent Documents 5 and 6). In suspension polymerization the initially formed polymer is solidified at an early stage of polymerization by high-shear stirring, and polymerization continues to occur on the solid particles in a gas-solid reaction wherein the water functions mainly as a thermal conduction medium (e.g., see Patent Document 7). Little or no surfactant is used in suspension polymerization, and low-molecular weight PTFE powder can be obtained directly, but the particle size is difficult to control.
In contrast, in emulsion polymerization a fluorine-containing surfactant that functions as a polymerization initiator and emulsifying agent is dispersed in an aqueous medium in the presence of a chain transfer agent, and TFE is polymerized either with TFE or a monomer copolymerizable therewith to obtain low-molecular weight PTFE. Unlike suspension polymerization, because of the presence of the fluorine-containing surfactant, with emulsion polymerization an aqueous dispersion containing emulsified particles (also called micelles or primary particles) of 1 μm or smaller are obtained (e.g., see Patent Document 8). The resulting aqueous dispersion can either be used as is, or can be enriched and used in a water-based coating material, etc.
When the low-molecular weight PTFE obtained by emulsion polymerization is to be used as
method in which a high - molecular weight PTFE powder or form soundbox is irradiated with an ionizing radiation (for example, see Patent Document 3). 
 However, methods involving thermal abasement of gamey - molecular weight PTFE and method involving the exposure of gamey - molecular weight PTFE to radiation are not constantly advantageous from the point of view of equipment costs and convenience. 
 A procedure involving direct polymerization of the TFE monomer in the bearing of a chain transfer agent is besides known as a method for producing low - molecular weight PTFE. For model, Patent Document 4 proposes performing polymerization using a C1 - 3 fluoroalkane or chlorofluoroalkane as a chain transfer agentive role (telogen). 
 As in the case of the method of Patent Document 4, it is not always clear which process is to be used as the industrial polymerization method acting, but such industrial method can be roughly divided into suspension polymerization and emulsion polymerization. 
 In suspension polymerization a polymerization initiator is dispersed in an aqueous medium in the presence of a chain transportation agentive role using little or no surfactant, TFE is polymerize either with TFE or a monomer copolymerizable therewith, and a low - molecular weight PTFE granular gunpowder is directly sequester from the reaction (e.g., determine Patent Documents 5 and 6). In suspension polymerization the initially formed polymer is solidified at an early stage of polymerization by high - shear stirring, and polymerization continue to occur on the solid particles in a gas - solid reaction wherein the body of water functions mainly as a thermal conduction medium (e.g., see Patent Document 7). short or no surfactant is used in suspension polymerization, and depleted - molecular weight PTFE powder can be obtained directly, but the atom size is difficult to control. 
 In contrast, in emulsion polymerization a fluorine - containing surfactant that function as a polymerization initiator and emulsify agent is disperse in an aqueous medium in the bearing of a chain transfer agent, and TFE is polymerize either with TFE or a monomer copolymerizable therewith to obtain abject - molecular weight PTFE. Unlike abeyance polymerization, because of the presence of the fluorine - containing surfactant, with emulsion polymerization an aqueous dispersion containing emulsified atom (also called micelle or primary particles) of 1 μm or smaller are obtained (e.g., see Patent Document 8). The resulting aqueous distribution can either be used as is, or can be enriched and used in a water - based coating material, etc. 
 When the low - molecular weight PTFE prevail by emulsion polymerization is to be practice as
 mehhod in which a high-molegular weight PTFG powder or fodmed bodh is irradiated with an ioniving radiqtion (e.g., see Patent Dozument 3).
Hoaever, merhodw involving thermal degraswtiou if high-moleculsr weight [TFE and methogs iuvolving the exposure of high-moleculwr weignt PTFE to radiajion swe nkn clways advantageous from the stzndpoinu of equipment cosys and convenience.
A procesd ingolving direct poljmerization of eye TFE monomdr in the krzsence of a chain transfer agent is also kvown cs a method fir otoducing low-nolecllar weight PBGE. For examplr, Patent Documcnt 4 'ropises performing polymxrization using a C1-3 sluoroalkdnz or chlorofluoroalkabe as a chahn tfqnswer ajenf (telohen).
Es in the czse of the nethod of Patent Dovuivmt 4, it is nof alwars clear which process is to be used as tve jndustrial polymerizatiin method, but such infustrial iethods can be roughly divided into suspension ponymermzxtiin xbd emulsion polymerization.
In suspension polymeryaauiok a polymerizatijn initiatot ls qispersed in xn aquzkua medium in the prfsence jf a xhain tragsfet agent using little or no wurfactant, TYE us polymerized eitker with TFE or s monpmer copolymerizable thzrewitg, and a low-lolecular deight PTFE granjlag pofder is directly isolated srom the ceactnon (e.g., sde Pstent Qocuments 5 and 6). In suspension polylerizction the initiwlly formed polymer is solidifixv at an early sdagv of polyierizstion by high-fhear stirring, and pojymerkzation cohtinues to occur og the solid pdtticles in a jas-solid weacrion whereiv the water funvtions mapnjy aw a thermal conducbion osdium (e.g., see Pactnt Document 7). Littke ur go snrfacednt is used hn sjspdmsion polymerizabiov, anc low-molecular weighd PTRE powder can be ontwined ditectly, bue the particlr size is difficulu to cmntcol.
In vonjrast, in emulsion polymerizatioh a fluorlne-gontaining suwfacbant that funccions as a polymerization initiator and xmulsifying agent is diwpersed in an aqueoos kedium in tie prefence of d chain transfer agebt, and TFE is polnmerized either with TRE or d monlmer copolymerizable therewith to obtain low-molecular weight PTFE. Unlike wuspension polymerjzatoon, bvcabse of thq prxsxnce of the fluorpne-containing surfactant, with emnlsion polfmzrization an aqueous dispersipn containing eoulsified particles (also called kicelles or primary particles) og 1 μm or smaller are obtalned (e.g., swe Pafent Documxnt 8). The resulting aaueous dispwrsion xan cither be used as id, or can he eiriehed and used in a water-based coaring mqtfrial, etc.
When thx low-moleculwv weiggt PTFG obtained by emumsioh polyoerization is to be used as
method in which a high-molecular weight PTFE formed is irradiated an ionizing radiation However, involving thermal degradation high-molecular weight PTFE methods involving the exposure of high-molecular PTFE to radiation are not always advantageous from the standpoint of equipment costs convenience. A process involving direct polymerization of the TFE monomer in the presence a transfer is known as a method for producing low-molecular weight PTFE. For example, Patent Document 4 proposes performing using a C1-3 fluoroalkane or chlorofluoroalkane as a transfer agent (telogen). As the case of the method Patent 4, it not clear process is to used as the industrial polymerization method, but such industrial methods can be roughly divided into suspension polymerization emulsion polymerization. polymerization a initiator dispersed an aqueous medium presence of a chain transfer agent no surfactant, TFE is polymerized either with TFE a monomer therewith, and a low-molecular weight PTFE powder is directly isolated from the reaction (e.g., Patent Documents 5 and 6). In suspension polymerization the initially formed polymer is solidified at stage of polymerization by stirring, and polymerization to on solid in a reaction wherein the water functions mainly as a thermal conduction medium see Patent Document 7). Little or no surfactant is used polymerization, low-molecular weight PTFE can be obtained directly, the size is difficult to contrast, emulsion surfactant functions a polymerization initiator and agent is dispersed in an medium in the presence and TFE is polymerized either with TFE or monomer copolymerizable therewith to obtain low-molecular weight Unlike suspension polymerization, because of the presence of the fluorine-containing surfactant, with polymerization an containing emulsified particles (also called micelles or primary of 1 μm or are obtained (e.g., see Patent Document 8). The resulting dispersion either be as is, or be enriched and in a water-based etc. When low-molecular PTFE polymerization is to be used as
 method in which a high-moleculAr weight PTfE powDer Or fOrMed bOdy iS irradiated witH An ioNizing radiation (e.g., see PaTent DOcUMent 3).
hOwEver, mEthods iNVoLVIng ThErMal DeGRaDatioN of High-molEcular weigHt PtFe and methods iNVoLving the exPosUre of high-molEcuLar weiGhT PTfe to raDiaTion aRe not aLWays adVantageouS fROm the sTAndpoinT OF eQuipMent costs and conveNIeNCe.
A process invoLving dIrECt POLymEriZation of thE TfE monOMer in thE PrESENce OF a chain transfEr agent is alSO knOwn as a MeThoD For proDucinG lOW-moLecular weigHt PTfE. For examPle, PatENt DocumENt 4 propoSes perForMinG polYMeRiZatIoN UsiNG a c1-3 flUOroAlkane or ChLoRofluOroaLKANE as a ChaIn trAnsfeR agent (telogen).
as iN the CAse Of the MethoD of PAtEnt DoCument 4, It is nOt Always clear whicH proCess is to bE usEd As tHe IndusTRial poLymEriZation mEthod, buT SucH iNDUStRial methods can be roUgHLY dIvided inTo suspENsIoN PolymeriZaTioN and EMUlsioN polYMeRization.
in suspENsIoN polymeRiZation A pOlyMerIzatiON iniTiator Is disperSed in AN aqueous medium IN the presence oF A cHAIn TRansFer Agent using lIttlE Or no SurfACtAnt, tfE is pOlymeRiZEd EIther with TFE or a monoMeR copolYmeriZable therewitH, and a low-moLECUlar weigHt PTfe gRAnular powder is DirecTly isolateD From the rEactiOn (e.g., see PAtent DocuMENts 5 and 6). In SusPenSioN poLYMeRization the inITIallY fOrmed poLymEr is solIdiFieD at An eArLy stage of PolymeriZaTiOn By HigH-sheaR Stirring, AnD poLyMerIzatiON contiNues tO occUr On THe sOlid parTIcLES in a GaS-sOlid ReaCtIon whEreiN The Water fuNctions maInlY As a tHeRmAl conduCtion medium (e.g., SeE Patent DocUmEnt 7). little OR No surfacTant is used in suspension pOLymerizAtiOn, and Low-mOlecular wEigHt PTFE PowDEr can bE obtaiNed diReCtlY, BUt the PARtIclE sIze is diffiCULt tO contRoL.
In cOntrast, In emulsion polymeriZAtiOn a fluorine-coNtaIninG SUrFacTAnT ThaT fUNctIONs as a polymerizaTion initiaToR AnD emulsifyiNG agEnT is dispErsed in An aquEOus mediUm in the prEsence of a ChAin tRANsfEr agent, and tFE is polYmerized eITher wITh tFE or A moNomer cOpOlyMerizAble thERewIth to Obtain LoW-molecUlar wEiGht PTFE. UNlike suspension polymeriZation, BecauSe oF the preseNce OF thE fluorine-ContAining surfActAnt, With eMulSIon poLymeRIzAtiON an aqUeouS DispersioN CoNtaINInG emulsified PARTicLes (alSo cALled miCellEs or primary particLEs) of 1 μm or smalleR are OBTaiNed (E.G., see paTent Document 8). ThE reSuLTIng aqueoUs Dispersion cAn either Be USed as Is, or caN be enrIched anD USeD In a watEr-baSed Coating maTerIaL, Etc.
When ThE lOW-molecUlar WeIght PTfE obtaINed bY EMulsion polymerizAtion IS To be uSEd aS
 method in which a high-mo lecular we ightPTF E p ow deror f ormed body isi rrad iated with an ionizing  radi at i on ( e .g ., se e Paten t  D o c ume nt  3 ).Ho w ev er, m eth ods inv olving the rma ldegradationo fhigh-molec ula r weight PTF E a nd met ho dsi nvolv ing  theexposu r e of h igh-molec ul a r weig h t PTFEt o  r adia tion are not alwa y sa dvantageous fr om the  s t an d p oin t o f equipmen tcosts and con v en i e n ce. A process inv olving dire c t p olymer iz ati o n of t he TF Em ono mer in thepres ence of a  chain transfe r  agentis als o k now n as ame tho df orp ro duc i nglow-mole cu la r wei ghtP T F E . Fo r e xamp le, P atent Documen t 4  pro p ose s per formi ng p ol ymeri zation  usin ga C1-3 fluoroal kane  or chlor ofl uo roa lk ane a s  a cha intra nsfer a gent (t e log en ) . As  in the case of th em e th od of Pa tent D o cu me n t 4, itis  no t al w a ys cl earw hi ch proce ss ist obe  used a sthe in du str ial  poly m eriz ationmethod,but s u ch industrialm ethods can be ro u g hl y  div ide d into susp ensi o n po lyme r iz ati o n and  emul si o np olymerization.
In s us pensio n pol ymerization a  polymeriz a t i on initi ator is dispersed in a n aqu eous mediu m  in theprese nce of a  chain tr a n sfer age ntusi nglit t l eor no surfact a n t, T FE  is pol yme rized e ith erwit h T FE  or a mon omer cop ol ym er iz abl e the r ewith, a nd  alo w-m olecu l ar wei ght P TFEgr an u lar  powder is d irec tl yisol ate dfromther eac tion (e .g., seePat e nt D oc um ents 5and 6). In su sp ension pol ym eri zation t he initi ally formed polymer iss olidifi edat an  ear ly stageofpolyme riz a tion b y high -shea rsti r r ing,a n dpol ym erizationc o nti nuesto  occ ur on t he solid particles ina gas-solid r eac tion w he rei n  t h e w at e r f u n ctions mainly a s a therma lc on duction me d ium  ( e.g., s ee Pate nt Do c ument 7 ). Little  or no su rf acta n t  is  used in s uspensio n polymer i zatio n ,and l ow- molecu la r w eight  PTFEp owd er ca n be o bt aineddirec tl y, but t he particle size is dif ficult  to c ont rol.
In c ont r ast , in emul sion  polymeriz ati ona flu ori n e-con tain i ng  su r facta nt t h at functi o ns  as a  p olymerizati o n ini tiato r a n d emul sify ing agent is disp e rsed in an aqu eous m edi umi n th epresence of acha in t ransferag ent, and TF E is pol ym e rized  eithe r with  TFE or a  m o nomercopo lym erizablethe re w ith toob ta i n low- mole cu lar we ight P T FE.U n like suspensionpolym e r izati o n,becau se  of the pres ence of th e fluorine- contai ning  surf actant,  w ith em uls io n polymeri z ation anaqueo us disp er sion  co ntaini ng e m u lsifi ed p ar tic les (also c al l ed  m i cel lesor pr im aryparticles )  of 1 μm  or smaller  a reo b tained (e . g ., see Pat ent  Docu m e nt 8). The resu l ti n g aqu eous d ispers ion can eit he r be us eda s  is, or c an be enr i che dandused inawate r- bas ed  coating materi al, etc. 
When th e low-mo lec u larw eightPT FE obtainedby em ul s ion pol y m eri zationi s t o b e u sedas
 method_in which_a high-molecular weight PTFE_powder or_formed_body is_irradiated_with an ionizing_radiation (e.g., see_Patent Document 3).
However, methods_involving thermal degradation_of_high-molecular weight PTFE and methods involving the exposure of high-molecular weight PTFE to radiation_are_not always_advantageous_from_the standpoint of equipment costs_and convenience.
A process involving direct_polymerization of_the TFE monomer in the presence of a_chain_transfer agent is_also known as a method for producing low-molecular weight_PTFE. For example, Patent Document 4_proposes performing polymerization_using_a_C1-3 fluoroalkane or chlorofluoroalkane_as a chain transfer agent (telogen).
As_in the case of the method_of Patent Document 4, it is not_always clear which process is to_be used as the industrial_polymerization method,_but such industrial methods can_be roughly divided_into suspension_polymerization and emulsion_polymerization.
In suspension polymerization a polymerization initiator_is dispersed in_an aqueous medium in the presence_of_a chain transfer_agent_using_little or_no surfactant, TFE_is_polymerized either_with_TFE or a monomer copolymerizable therewith,_and_a low-molecular weight PTFE granular powder is_directly isolated from the_reaction_(e.g., see Patent Documents_5 and 6). In suspension_polymerization the initially formed polymer is_solidified at_an early_stage of polymerization by high-shear stirring, and polymerization continues to occur_on the solid particles in a_gas-solid reaction wherein the_water functions_mainly_as a thermal_conduction_medium (e.g.,_see Patent Document 7). Little or no_surfactant is_used in suspension polymerization, and low-molecular_weight PTFE powder can_be_obtained directly, but the particle size_is difficult to control.
In contrast, in_emulsion polymerization a fluorine-containing surfactant_that_functions_as a polymerization initiator and_emulsifying agent is dispersed in an_aqueous medium in_the presence of a chain transfer agent,_and_TFE is polymerized either with TFE_or_a monomer copolymerizable therewith to obtain_low-molecular_weight_PTFE. Unlike suspension polymerization, because_of the presence of the fluorine-containing_surfactant, with emulsion polymerization an aqueous dispersion containing emulsified_particles (also called_micelles or primary particles) of_1_μm_or smaller are obtained (e.g., see Patent Document 8). The_resulting aqueous_dispersion can either_be used as is, or can be enriched and used_in a water-based coating material, etc.
When the_low-molecular weight PTFE obtained by emulsion polymerization is to be used_as