JP4589890B2 - Optical transmission - Google Patents

Description

  The present invention relates to an optical transmission body, and more particularly to an optical transmission body made of a polyvinyl chloride resin composition having high transparency.

Polyvinyl chloride resin, chlorinated polyvinyl chloride resin and copolymer resin of vinyl chloride and ethylene, vinyl acetate, etc. are excellent in acid resistance, alkali resistance, water resistance, electrical insulation, flame resistance, mechanical strength, and pipe material It is widely used in applications such as building materials, agricultural supplies, electronic and electrical supplies, and daily necessities.
However, since the polyvinyl chloride resin is not so excellent in transparency, it is usually used in a colored state. Some polyvinyl chloride resins have improved transparency, but the transparency is such that light is transmitted with a thickness of several millimeters at most.
On the other hand, a polyacrylic acid-based resin having excellent transparency is expected to be used as an optical resin material, and for example, development of an optical fiber is being promoted (for example, Patent Document 1).

In general, a resin with few carbon-hydrogen bonds that cause light absorption in the near infrared to infrared region (600 to 1550 nm) should theoretically have excellent transparency. For example, the absorption loss due to carbon-hydrogen bonds of polymethyl methacrylate at a wavelength of 650 nm is estimated to be 96 dB / km, whereas the absorption loss of carbon-hydrogen bonds in polyvinyl chloride is 78 dB / km, and chlorine In the case of chlorinated polyvinyl chloride, it is estimated that the absorption loss is further smaller than 78 dB / km as the chlorine content increases. Therefore, even a polyvinyl chloride resin can be used as an optical resin material by improving transparency and reducing light absorption.
Nevertheless, the polyvinyl chloride resin produced industrially by the radical polymerization method is actually not excellent in transparency and has not been developed for optical applications. this is,
1) Dehydrochlorination is caused by an unstable structure such as a branched structure of resin due to molding heat, and the resulting carbon-carbon double bond absorbs light, particularly short wavelength light.
2) At the time of polymerization, the aggregate of polymer particles generated because the polymer is not dissolved in the monomer scatters light.
3) This is because the microcrystals present in the resin scatter light.

WO93 / 08488 pamphlet

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical transmission body made of a polyvinyl chloride resin composition that is excellent in transparency and acceptable as an optical resin material.

The optical transmission body of the present invention comprises a compound selected from diphenylsulfone and derivatives thereof in a resin composition mainly composed of a polyvinyl chloride resin having a chlorine content of 62% or more and 73% or less,
The compound selected from the diphenylsulfone and its derivatives is 25% by weight or less, and the diphenylsulfone derivative is composed of 4,4′-dichlorodiphenylsulfone and 3,3 ′, 4,4′-tetrachlorodiphenylsulfone. It is at least one selected from the group .

This optical transmission body is preferably made of a resin composition containing as a main component a polyvinyl chloride resin having a generated hydrogen chloride amount of 150 ppm or less under heating at 200 ° C. for 30 minutes.
It preferably has a refractive index distribution .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to obtain the optical transmission body which consists of a polyvinyl chloride-type resin composition excellent in transparency and accept | permitted as an optical resin material.

The optical transmission body of the present invention comprises a resin composition containing a polyvinyl chloride resin as a main component. Here, “main component” usually means that 50% by weight or more of the resin composition contains a polyvinyl chloride resin, but it may not necessarily be 50% by weight or more. It is also included that the largest amount of component is a polyvinyl chloride resin.
This resin composition contains (1) a polyvinyl chloride resin as a main component, and the calorific value of an endothermic peak existing at 110 to 210 ° C. is from 0 mJ / mg to 4.0 mJ / mg, or (2) The main component is a polyvinyl chloride resin having a chlorine content of 62% or more and 73% or less, or (3) the main component is a polyvinyl chloride resin, and the solubility parameter is 7.5 to 12.0. It is preferable that the substance which is (cal / cm ³ ) ^1/2 is contained in less than 50% by weight, or two or more, and all of these are provided.

In the present invention, the polyvinyl chloride resin is a (co) polymer obtained by polymerizing or copolymerizing a vinyl chloride monomer and / or a monomer copolymerizable with vinyl chloride, or a chlorinated product thereafter.
Monomers copolymerizable with vinyl chloride include all known vinyl monomers, for example, α-olefins such as ethylene, propylene and butylene: vinyl esters such as vinyl acetate and vinyl propionate: ethyl vinyl ether, Vinyl ethers such as butyl vinyl ether: (meth) acrylic acid esters such as methyl (meth) acrylate, butyl (meth) acrylate, and hydroxyethyl (meth) acrylate. These may be used alone or in combination of two or more.

What is suitable as the polyvinyl chloride resin of the present invention, that is, a polyvinyl chloride resin having a small irregular structure such as a branched structure or a head-to-head structure is copolymerized with, for example, the above-described vinyl chloride monomer and / or vinyl chloride. Possible monomers,
General formula
ZrX ¹ X ² X ³ X ⁴
(Wherein, X ¹ , X ² , X ³ , X ⁴ are halogen atoms, alkyl groups, alkoxy groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aryloxy groups, etc.)
General formula
AlY ¹ Y ² Y ³
(Wherein Y ¹ , Y ² , and Y ³ are a halogen atom, an alkyl group, an alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, etc.) It can be obtained by (co) polymerization under the condition or (co) polymerization in the presence of alkyllithium. These (co) polymers may be post-chlorinated.

Examples of the halogen atom for X ¹ , X ² , X ³ and X ⁴ include fluorine, chlorine, bromine and iodine atoms.
As the alkyl group, those having 1 to 6 carbon atoms are suitable, and examples thereof include methyl, ethyl, propyl, i-propyl, n-butyl, t-butyl and the like.
As the alkoxy group, those having 1 to 6 carbon atoms are suitable, and examples thereof include methoxy, ethoxy, propoxy, i-propoxy, n-butoxy, t-butoxy and the like.
As the substituted or unsubstituted aryl group, those having 6 to 9 carbon atoms are suitable. Moreover, a halogen atom is mentioned as a substituent. Examples thereof include phenyl, tolyl, xylyl, cumenyl, mesityl, naphthyl, phenyl chloride, tolyl chloride, xylyl chloride and the like.
As the substituted or unsubstituted aryloxy group, those having 6 to 9 carbon atoms are suitable. Moreover, a halogen atom is mentioned as a substituent. Examples include phenoxy, tolyloxy, xyloxy, cumenyloxy, mesityloxy, naphthyloxy, phenoxy chloride, tolyloxy chloride, xylyloxy chloride, and the like.
Of these, zirconium alkoxides and zirconium aryloxides, which are tetra-substituted alkoxy groups and aryloxy groups, are preferred in that the resulting vinyl chloride resin has fewer branched structures, and X ¹ to X ⁴ More preferably, all are the same substituent.

  Specific examples of the zirconium compound include zirconium alkoxides such as zirconium tetra-n-butoxide, zirconium tetra-t-butoxide and zirconium tetraisopropoxide; zirconium aryloxides such as zirconium tetraphenoxide; dicyclopentadienyl; Zirconenes such as zirconium dichloride and dicyclopentadienyl zirconium dibutoxide; cyclopentadienyl zirconium trichloride, cyclopentadienyl zirconium tributoxide, pentamethylcyclopentadienyl zirconium tributoxide, pentamethylcyclopentadi And half-zirconocenes such as enilzirconium triphenoxide.

The concentration of the zirconium compound in the polymerization system is not particularly limited, but from the viewpoint of securing the polymerization degree of the vinyl chloride resin, reducing the amount of remaining zirconium, and improving the polymerization efficiency, the concentration of zirconium is 10 ^−1. It is preferably in the range of -10 ^-8 mol / l.

Examples of Y ¹ , Y ² and Y ³ are the same as those exemplified for X ¹ to X ⁴ .
Specific examples of the aluminum compound include trimethylaluminum, triethylaluminum, tri-i-butylaluminum, tri-n-hexylaluminum, ethylaluminum sesquichloride, diethylaluminum chloride, ethylaluminum dichloride, i-butylaluminum dichloride, diethylaluminum. Examples include ethoxide.

  Examples of the alkylaluminoxane include methylaluminoxane and ethylaluminoxane.

  In the present invention, trimethylaluminum, triethylaluminum, ethylaluminum dichloride, and methylaluminoxane are more preferred because the production efficiency and branched structure of the resulting vinyl chloride resin are less. These can be used alone or in combination of two or more.

The concentration of the aluminum compound and / or alkylaluminoxane in the polymerization system is such that the molar ratio of aluminum / zirconium is 1 to 10 ^{5 in} terms of the molar ratio with zirconium from the viewpoint of improving the polymerization yield and suppressing the increase in the amount of remaining metal. It is preferable that it is the range of these.

  Specific examples of the alkyl lithium include methyl lithium, ethyl lithium, n-propyl lithium, i-propyl lithium, n-butyl lithium, s-butyl lithium, and t-butyl lithium.

The concentration of the alkyl lithium in the polymerization system is not particularly limited, but from the viewpoint of ensuring the degree of polymerization of the vinyl chloride resin, reducing the remaining alkyl lithium, and further improving the polymerization efficiency, the alkyl lithium concentration is 10 ⁻ It is preferably in the range of ¹ to 10 ⁻⁴ mol / l.

Polymerization or copolymerization is carried out in a reaction vessel under an inert gas atmosphere such as nitrogen or argon, with vinyl chloride monomer and / or vinyl chloride monomer, copolymerizable monomer, zirconium compound, aluminum compound, alkylaluminoxane or alkyl. Lithium is added to initiate the polymerization reaction. A polymerization reaction may be carried out by optionally adding a solvent. In addition to the reactor, it may be dissolved or diluted with a solvent or the like.
The temperature at the time of polymerizing a suitable polyvinyl chloride resin in the present invention is not particularly limited, but the reaction rate becomes slow when it becomes low, and it takes time to polymerize to a predetermined yield, Considering that when it becomes higher, a side reaction such as a stop reaction or a chain reaction easily proceeds, −50 ° C. to 60 ° C. is appropriate. The reaction pressure is not particularly limited.

After adding a deactivator such as methanol or water to the reaction mixture obtained by the above polymerization and performing deactivation treatment, deashing treatment with acid / alkali, residual catalyst removal treatment with a porous adsorbent, etc. By performing, a (co) polymer can be obtained. The polyvinyl chloride resin suitably used in the present invention can be produced by employing any known method. For example, a method called an ionic polymerization method can be suitably used. From another viewpoint, a bulk polymerization method, a solution polymerization method, and the like can be given. In addition, as a solvent in the case of performing solution polymerization, although it does not specifically limit, what the solvent itself does not modify | denature during superposition | polymerization is selected. For example, hexane, dichloromethane, toluene and the like can be mentioned.
As a method for obtaining a chlorinated product by chlorinating a (co) polymer, a known chlorination method or a method according to this can be used. For example, water suspension thermal chlorination method, water suspension photochlorination Method, solution chlorination method and the like. In addition, if a radical generator such as hydrogen peroxide is added during chlorination, the resulting chlorinated product will form a structure that serves as a base point for dehydrochlorination in the main chain, so do not add it as much as possible. Is preferred. The addition amount in the case of adding a radical generator is suitably 50 ppm or less.

In the present invention, the polyvinyl chloride-based resin is preferably a post-chlorinated product from the viewpoint of low dehydrochlorination property and improved transparency. A chlorinated product obtained by the conversion method is preferred.
In the present invention, the heat quantity of the endothermic peak existing at 110 to 210 ° C. is 0 mJ / mg or more and 4.0 mJ / mg or less, that is, the crystallinity is extremely low, and the aggregate of polymer particles In addition, the light scattering by the crystal is small and the transparency is excellent.
The calorific value of this endothermic peak is about 3.8 mJ / mg or less, 3.6 mJ / mg or less, 3.5 mJ / mg or less, 3.0 mJ / mg or less, and further 2.0 mJ / mg or less. Is preferred. This is because by reducing the crystallinity, it is possible to reduce transmission loss, particularly scattering loss, in the optical transmission body.

In the polyvinyl chloride resin composition, means for reducing the heat quantity of the endothermic peak present at 110 to 210 ° C. to 4.0 mJ / mg or less is not particularly limited, and a method of chlorinating the (co) polymer described above, Various methods such as a method of copolymerizing a monomer copolymerizable with vinyl chloride, a method of blending a polyvinyl chloride resin with a compound compatible with the polyvinyl chloride resin, a combination of these methods, and the like can be mentioned.
The amount of heat of the endothermic peak existing at 110 to 210 ° C. is a value measured in the following manner.
Using a differential scanning calorimeter, the temperature was raised from 20 ° C. to 200 ° C. at 10 ° C./minute, then the temperature was lowered from 200 ° C. to 20 ° C. at 10 ° C./minute, and then increased from 20 ° C. to 280 ° C. at 10 ° C./minute. It is a value calculated by measuring the calorific value of the endothermic peak existing at 110 to 210 ° C. when heated and dividing by the sample weight as the calorific value per unit weight.

In the present invention, the chlorine content of 62% or more and 73% or less means that the chlorine atom in the resin is 62 to 73% by weight, that is, the chlorine content is high. Thereby, light scattering due to the presence of aggregates and crystal structures of polymer particles is small, the transparency is excellent, and the moldability can be improved.
The chlorine content is more preferably about 63% or more, about 65% or more, about 66% or more, about 72% or less, about 71% or less, or about 70% or less.
Examples of the method for increasing the chlorine content include the chlorination method as described above.
The chlorine content can be measured by a method based on JIS K 7229.
In the present invention, when a substance having a solubility parameter (SP value) of 7.5 to 12.0 (cal / cm ³ ) ^1/2 is used, white turbidity occurs due to phase separation in a polyvinyl chloride resin coexisting system. It means that scattering can be suppressed and optical transmission loss can be maintained well.

The SP value can be calculated by the following equation. (See Hoy et al. (POLYMER HANDBOOK, Third edition, VII / 519 (published by Wiley Interscience)).
SP = dΣG / M
(In the formula, d and M represent the density and molecular weight of the polymer, respectively, and G represents a group Molar Attraction Constant).
The SP value is preferably about 7.8 or more, about 8.0 or more, about 8.2 or more, about 11.8 or less, about 11.6 or less, or about 11.5 or less. This is to ensure transparency while maintaining uniform mixing with the polyvinyl chloride resin.
In addition to the polyvinyl chloride resin, a so-called scattering inhibitor can be mixed in the polyvinyl chloride resin composition of the present invention. Here, the scattering inhibitor means one that reduces light scattering by reducing the crystallinity of a polyvinyl chloride resin, which is one of the physical properties of an optical fiber. Note that the scattering inhibitor may be an agent that arbitrarily extinguishes the particle structure or an agent that can increase or decrease the refractive index. Examples of the scattering inhibitor include those having the above-mentioned SP value in the range of 7.5 to 12.0 (cal / cm ³ ) ^1/2 .

Examples of such a scattering inhibitor include poly (meth) acrylic acid alkyl esters having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, benzyl poly (meth) acrylate, poly Examples include phenyl (meth) acrylate, cyclohexyl poly (meth) acrylate, 1-phenylethyl poly (meth) acrylate, polyvinyl acetate, polyacrylonitrile, and polychlorostyrene. In particular, polymethyl methacrylate (SP value: 9.2 (cal / cm ³ ) ^1/2 ) is preferable.

  Also, epoxidized soybean oil, epoxidized linseed oil, polypropylene adipate, polypropylene sebacate, chlorinated polyethylene, chlorinated paraffin; phosphate esters such as triphenyl phosphate, triethyl phosphate, tri-2-ethylhexyl phosphate; adipine Adipic acid esters such as di-2-ethylhexyl acid, dibutyl adipate, diisodecyl adipate; azelaic acid esters such as di-2-ethylhexyl azelate, diisooctyl azelate; di-2-ethylhexyl sebacate, dibutyl sebacate, etc. Sebacic acid ester: A polymer or oligomer having a basic structure obtained by polycondensation of dibasic acid and glycol can be used. Examples of the dibasic acid include sebacic acid, azelaic acid, adipic acid, and phthalic acid. Examples of the glycol include propylene glycol, ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, hexanediol and the like. Furthermore, phthalic acid esters such as di-2-ethylhexyl phthalate, diisodecyl phthalate and isotridecyl phthalate; pyromellitic acid esters such as pyromellitic acid octyl ester; esters obtained by esterification reaction of trimellitic acid and alcohol, That is, the following formula (I)

（式中、Ｒ¹〜Ｒ³は、同一又は異なって、アルキル基を示す。）
で表わされるトリメリット酸エステル；旭電化製ＵＬ−６等の下記式（II）

(In formula, R < ¹ > -R < ³ > is the same or different and shows an alkyl group.)
Trimellitic acid ester represented by the following formula (II) such as UL-6 manufactured by Asahi Denka

（式中、Ｒ⁴は、任意の官能基、ｘは１〜４の整数を示す。）
で表されるジペンタエリストールエステル等を用いてもよい。なお、散乱抑制剤の候補としては、ジフェニルスルホンおよびジフェニルスルホン誘導体、ジフェニルスルフィド、ジフェニルスルホキシド等の硫黄化合物も例示される。ジフェニルスルホン誘導体としては４，４'−ジクロロジフェニルスルホン、３，３'，４，４'−テトラクロロジフェニルスルホン等が挙げられる。

(In the formula, R ⁴ represents an arbitrary functional group, and x represents an integer of 1 to 4.)
Dipentaerystol ester represented by the following may be used. Examples of the scattering inhibitor candidate include sulfur compounds such as diphenyl sulfone and diphenyl sulfone derivatives, diphenyl sulfide, and diphenyl sulfoxide. Examples of the diphenylsulfone derivative include 4,4′-dichlorodiphenylsulfone and 3,3 ′, 4,4′-tetrachlorodiphenylsulfone.

等が例示される。なお、置換基Ｒ⁴は、ｘが２〜４の場合には、その数に応じて２〜４価の置換基となり得る。具体的には、ｘが２、Ｒ⁴が−（ＣＨ₂）₄−である化合物が挙げられる。
トリメリット酸エステルとしては、例えば、トリメリット酸トリブチル、トリメリット酸トリ−２-エチルヘキシル、トリメリット酸トリｎ−オクチル、トリメリット酸トリイソノニル、トリメリット酸トリイソデシル等のトリメリット酸トリアルキルが挙げられる。また、トリメリット酸と複数種のアルコールとのエステルであってもよい。なかでも、トリメリット酸トリ-２-エチルヘキシル、トリメリット酸トリイソデシルが好ましい。 Here, the alkyl groups of R ^{1 to} R ³ may be different from each other, but it is preferable that three are the same. Further, an alkyl group having 1 to 12 carbon atoms, and more preferably 4 to 10 carbon atoms is preferable.
Examples of R ⁴ include lower alkyl groups having 1 to 6 carbon atoms (methyl, ethyl, propyl, n-butyl, t-butyl, etc.), aryl groups (phenyl, tolyl, xylyl, biphenyl, etc.),

Etc. are exemplified. Incidentally, the substituent R ^4, when x is 2 to 4 can be a divalent to tetravalent substituent in accordance with the number. Specifically, a compound in which x is 2 and R ⁴ is — (CH ₂ ) ₄ — is exemplified.
Examples of trimellitic acid esters include trialkyl trimellitic acid such as tributyl trimellitic acid, tri-2-ethylhexyl trimellitic acid, tri-n-octyl trimellitic acid, triisononyl trimellitic acid, and triisodecyl trimellitic acid. . Moreover, the ester of trimellitic acid and multiple types of alcohol may be sufficient. Of these, tri-2-ethylhexyl trimellitic acid and triisodecyl trimellitic acid are preferable.

  As the scattering inhibitor, sulfur compounds (especially diphenyl sulfone), phosphate esters (particularly triphenyl phosphate), trimellitic acid esters, and dipentaerystol esters are particularly preferable. These are relatively high or low in refractive index (for example, diphenyl sulfone and triphenyl phosphate have a high refractive index of 1.630, trimellitic acid ester has a refractive index of 1.480 to 1.490, dipentaerystol ester (ULA manufactured by Asahi Denka) This is because the refractive index of -6) is as low as 1.456), and can be adjusted to an appropriate value by increasing or decreasing the refractive index of the polyvinyl chloride resin composition.

The addition of such a scattering inhibitor is suitably less than 50% by weight in the polyvinyl chloride resin composition. This is to maintain the characteristics of the polyvinyl chloride resin predominately.
In particular, when a sulfur compound, phosphate ester, trimellitic acid ester and / or dipentaerystol ester is contained in the polyvinyl chloride resin composition, it is preferably contained at 25% by weight or less. Thereby, the glass transition point of a polyvinyl chloride-type resin composition can be maintained at a suitable value, and required intensity | strength can be ensured.

  Moreover, when blending a scattering inhibitor, two or more kinds of compounds having different refractive indexes may be blended. The two or more kinds of compounds preferably contain a compound having a high refractive index and a compound having a low refractive index as compared with the refractive index of the base resin composition. By using such a high refractive index compound and a low refractive index compound in combination, the same refractive index difference is obtained as compared with the case where only a high refractive index compound or only a low refractive index compound is blended. Therefore, the amount of the scattering inhibitor added to the resin composition can be relatively reduced. For this reason, a glass transition point becomes comparatively high and the heat resistance of the optical transmission body obtained by this can be improved.

In this case, the conversion degree of polymerization defined by the following formula is preferably in the range of 400 to 1000. More preferably, it is the range of 500-800. This is for facilitating molding while ensuring the necessary strength.
Degree of polymerization = Degree of polymerization of polyvinyl chloride resin x (Polyvinyl chloride resin blending ratio / (Polyvinyl chloride resin blending ratio / 1.5) + Scattering inhibitor blending ratio) /1.5
The scattering inhibitor in the above formula is particularly preferably a sulfur compound, a phosphate ester, a trimellitic acid ester and / or a dipentaerystol ester among those exemplified above.

As the scattering inhibitor, any one of the above-mentioned substances having an SP value of 7.5 to 12.0 (cal / cm ³ ) ^1/2 may be used singly or in combination. Further, a scattering inhibitor having an SP value outside this range and / or a so-called dopant may be used in combination.

  In the present invention, the polyvinyl chloride resin is preferably such that the amount of hydrogen chloride generated under heating at 200 ° C. for 30 minutes is 150 ppm or less. It is for suppressing the production | generation of a carbon-carbon double bond at the time of shaping | molding, and reducing light absorption.

The method for measuring the amount of generated hydrogen chloride is as follows.
First, 1 g of polyvinyl chloride resin is supplied to a test tube, sealed with a heat-resistant rubber stopper with a tube, and the test tube is immersed in a 200 ° C. oil bath from the bottom 2/3 and heated. The gas generated from the test tube is collected with 100 ml of ion exchange water through the tube for 20 minutes. The pH of ion exchange water is measured 20 minutes after the start of collection, and the amount of hydrogen chloride generated is calculated from the difference from the pH of ion exchange water before the start of collection.

  The polyvinyl chloride resin composition constituting the optical transmission body of the present invention does not impair the acid resistance, alkali resistance, water resistance, electrical insulation, flame resistance, and mechanical strength, which are the characteristics of the polyvinyl chloride resin. In the range, if necessary, a compounding agent such as a heat stabilizer, a heat stabilization aid, a lubricant, a processing aid, a heat resistance improver, an antioxidant, a light stabilizer and the like may be blended. If these compounding agents are used when shape | molding vinyl chloride-type resin, the kind will not be limited, respectively, It can use individually or in combination of 2 or more types, respectively.

  Examples of the heat stabilizer include dimethyltin mercapto, dibutyltin mercapto, dioctyltin mercapto, dibutyltin malate, dibutyltin malate polymer, dioctyltin malate, dioctyltin malate polymer, dibutyltin laurate, dibutyltin laurate polymer, etc. Organic tin stabilizers, lead stearate, dibasic lead phosphite, tribasic lead sulfate and other lead stabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, barium-cadmium stabilizers Agents and the like.

Examples of the stabilizing aid include epoxidized soybean oil, epoxidized linseed bean oil, epoxidized tetrahydrophthalate, epoxidized polybutadiene, and phosphate ester.
Examples of the lubricant include an internal lubricant and an external lubricant. The internal lubricant is a lubricant added for the purpose of reducing the flow viscosity of the molten resin during thermoforming and preventing frictional heat generation. For example, lauryl alcohol, stearyl alcohol, stearic acid, butyl stearate, glycerin monostearate , Epoxidized soybean oil, bisamide and the like. The external lubricant is a lubricant added for the purpose of enhancing the sliding effect between the molten resin and the mold surface during thermoforming, and examples thereof include montanic acid wax, paraffin wax, polyethylene wax, and ester wax.

Examples of the processing aid include acrylic processing aids which are alkyl acrylate-alkyl methacrylate copolymers having a weight average molecular weight of 100,000 to 2,000,000. Specific examples include n-butyl acrylate-methyl methacrylate copolymer. And 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer.
Examples of the heat resistance improver include a heat resistance improver such as an α-methylstyrene type and an N-phenylmaleimide type.

Examples of the antioxidant include phenolic antioxidants.
Examples of the light stabilizer include hindered amine light stabilizers.
The method for mixing the blend and the polyvinyl chloride resin composition is not particularly limited, and examples thereof include a hot blend method, a cold blend method, and a solution mixing method.

The molding method of the optical transmission body of the present invention is not particularly limited, but a molding method that requires as little heat energy as possible during molding is preferred in order to suppress the formation of double bonds that cause light absorption.
For example, a method may be mentioned in which a solution is prepared by dissolving the polyvinyl chloride resin composition of the present invention in an organic solvent such as tetrahydrofuran, and the solution is cast.
When molding by a conventionally known method having excellent productivity such as extrusion molding, injection molding, blow molding, roll molding, calender molding, press molding, etc., in particular, heating at 200 ° C. for 30 minutes. It is preferable to use a polyvinyl chloride resin composition whose generated hydrogen chloride amount is 150 ppm or less, and a resin composition mainly composed of a polyvinyl chloride resin having less irregular structure such as a branched structure or a head-to-head structure It is more preferable to use a product.
In order to suppress the formation of double bonds, a low molecular weight material having an SP value of 7.5 to 12.0 (cal / cm ³ ) ^1/2 is mixed with less than 50% by weight, and the molding temperature is obtained by the plasticizing effect A method of lowering is also effective.

The polyvinyl chloride resin composition of the present invention preferably contains no foreign matter. Although the removal method of a foreign material is not specifically limited, The method etc. by removing the solvent after filtering the solution which melt | dissolved the polyvinyl chloride-type resin composition in organic solvents, such as tetrahydrofuran, etc. are mentioned. These methods are preferably performed in a clean room.
Examples of the material of the filter used for filtration include alumina ceramics and polytetrafluoroethylene, but alumina ceramics are preferable from the viewpoint of filtration accuracy and chemical resistance.
A sufficient effect can be obtained by filtering only the main filter once or more, but it is preferable to perform multistage filtration or circulation filtration. If the pore size of the filter is 0.1 μm or less, a sufficient effect can be obtained. It is preferable to use a filter having a pore diameter of about 0.05 μm because a high effect is obtained with respect to the filtration rate and the foreign matter removal rate.

The method for removing the solvent is not particularly limited, and examples thereof include a spray drying method and a method using an extruder with a devolatilizing port.
The degree of polymerization of the polyvinyl chloride resin of the present invention is not particularly limited, but it is preferably 500 or more and 1000 or less because the balance between mechanical properties and moldability is excellent.
Furthermore, the optical transmission body of the present invention preferably has a refractive index distribution. Here, the refractive index distribution means a region where the refractive index changes along a specific direction of the optical transmission body. For example, in the refractive index distribution type optical fiber, the refractive index distribution is a curve close to a parabola in a radial direction from the center of the fiber, or gradually decreases with a constant width.

The method of adjusting the refractive index is not particularly limited, and is adjusted by a method of changing the chlorine content, a refractive index of a substance having an SP value of 7.5 to 12.0 (cal / cm ³ ) ^1/2 and a mixing ratio thereof. And a method of adjusting by a blending ratio of trimellitic acid ester, a method of adjusting by a blending ratio of sulfur compound (for example, diphenylsulfone) and / or phosphate ester (for example, triphenyl phosphate), and the like.
As a method for forming an optical transmission body having a refractive index distribution, a method known in this field can be used. For example, a multilayer extrusion method, a casting method and the like are exemplified while changing the composition.
In the case of multilayer extrusion, if the total additive concentration of each layer is made substantially equal using a mixture of two compounds whose refractive index is higher and lower than that of the base resin composition, the melt viscosity of each layer can be made substantially equal. It becomes easy to control the smoothness of the interface.

The optical transmission body of the present invention may be covered with a clad layer made of another material having a refractive index lower than that of the optical transmission body.
Hereinafter, embodiments of the optical transmission body of the present invention will be described in detail, but the present invention is not limited to the following examples.
Example 1
A 50-liter jacketed stainless steel polymerization vessel equipped with a stirrer and a reflux condenser was degassed, and steam was blown from the reflux condenser to raise the temperature inside the polymerization vessel to 80 ° C., and deionization at 50 ° C. 25000 g of water, 400 g of 3% solution partially saponified polyvinyl alcohol, and 200 g of 3% hydroxypropylmethylcellulose were fed. Thereafter, the inside of the reaction vessel was degassed to a water vapor pressure of +0.01 kPa, and 15 kg of vinyl chloride monomer was supplied while stirring. Next, 5 g of benzoyl peroxide was supplied into the polymerization vessel, and then the temperature was raised to 77 ° C. to carry out polymerization.

When the temperature in the polymerization vessel reached 77 ° C, the operation of the reflux condenser was started, and the temperature in the polymerization vessel was maintained at 77 ° C.
When the pressure in the polymerization vessel dropped to 1.1 MPa, unreacted vinyl chloride monomer was removed while flowing the water through the jacket and cooling the inside of the polymerization vessel. The obtained resin was washed with deionized water, dehydrated and dried to obtain a powdered vinyl chloride resin having a polymerization degree of 550.
The obtained polyvinyl chloride resin is supplied together with deionized water to a jacketed glass-lined pressure-resistant reactor equipped with a stirrer and stirred to disperse the polyvinyl chloride resin in deionized water with a vacuum pump. Air in the reaction vessel was sucked in, decompressed until it reached -78.4 kPa, and nitrogen gas was supplied until it reached normal pressure. Next, the oxygen in the reaction vessel was removed by suction again with a vacuum pump.

The heated oil was supplied to the jacket and heated to raise the temperature in the reaction vessel to 70 ° C. When the temperature in the reaction vessel reached 70 ° C., chlorine gas began to be supplied, and the chlorination reaction was advanced to 110 ° C. The generated hydrogen chloride concentration in the reaction vessel was measured, the chlorine content of the polyvinyl chloride resin was calculated, and the supply of chlorine gas was stopped when the chlorine content reached 64.3% by weight.
Next, unreacted chlorine gas is removed, and the resulting resin is washed with deionized water, dehydrated and dried to obtain a chlorinated polyvinyl chloride resin having a powdery chlorine content of 64.3% and a polymerization degree of 550. Obtained.
Similarly, chlorinated polyvinyl chloride resins having a degree of polymerization of 550 having chlorine contents of 66.5%, 68.3% and 70.0% were obtained.

  Resin concentration of chlorinated polyvinyl chloride having a chlorine content of 64.3% and a polymerization degree of 550 in a 10% by weight tetrahydrofuran solution (solution A), a chlorine content of 66.5% and a polymerization degree of 550 10 wt% tetrahydrofuran solution (solution B), chlorine content 68.3%, chlorinated polyvinyl chloride resin concentration 10 wt% tetrahydrofuran solution (solution C) with a polymerization degree 550, chlorine content 70.0%, polymerization degree A 550 chlorinated polyvinyl chloride solution having a resin concentration of 10% by weight in tetrahydrofuran (solution D) was prepared and filtered through an alumina ceramic filter having a pore diameter of 0.05 μm.

  Thereafter, the solution A is repeatedly supplied and dried using a tube pump in a cylindrical container having an inner diameter of 20 mm that rotates around the central axis, and is deposited to a thickness of 1 mm on the inner surface of the cylindrical container. Repeat drying to deposit 2 mm, then supply and dry solution C in the same manner to deposit 3 mm, and finally solution D to supply and dry in the same manner to deposit 3.5 mm, diameter 20 mm, length An optical fiber preform having a refractive index profile of 450 mm was obtained.

The obtained preform was supplied to a cylindrical heater set at 140 ° C., and the central cavity was heated and stretched while decompressing to obtain an optical fiber having a refractive index distribution with a diameter of 0.6 mm.
The obtained optical fiber was cut out, and the heat quantity and transmission loss of an endothermic peak existing at 110 to 210 ° C. were measured. The results are shown in Table 1.

なお、１１０〜２１０℃に存在する吸熱ピークの熱量は、セイコー電子工業社製示差走査熱量計で測定した（以下、同じ）。光ファイバーの伝送損失は、Ｏｃｅａｎ Ｏｐｔｉｃｓ社製スペクトロメーター及び白色光源を用いカットバック法により測定した（以下、同じ）。
また、樹脂の塩素含有率は、ＪＩＳ Ｋ ７２２９に準拠して測定した。

In addition, the calorie | heat amount of the endothermic peak which exists in 110-210 degreeC was measured with the Seiko Electronics Co., Ltd. differential scanning calorimeter (Hereafter, the same). The transmission loss of the optical fiber was measured by the cut-back method using a spectrometer and a white light source manufactured by Ocean Optics (hereinafter the same).
Further, the chlorine content of the resin was measured in accordance with JIS K 7229.

(Example 2)
A 50-liter jacketed stainless steel polymerization vessel equipped with a stirrer and a reflux condenser was degassed, and steam was blown from the reflux condenser to raise the temperature inside the polymerization vessel to 80 ° C., and deionization at 50 ° C. 25000 g of water, 300 g of 3% solution partially saponified polyvinyl alcohol, and 150 g of 3% hydroxypropylmethylcellulose were fed. Thereafter, the inside of the reaction vessel was degassed to a water vapor pressure of +0.01 kPa, and 15 kg of vinyl chloride monomer was supplied while stirring. Subsequently, 5 g of t-butyl peroxypivalate was supplied into the polymerization vessel, and then the temperature was raised to 72 ° C. to perform polymerization. When the temperature in the polymerization reactor reached 72 ° C., the operation of the reflux condenser was started, and the temperature in the polymerization reactor was maintained at 72 ° C.

When the pressure in the polymerization vessel drops to 0.9 MPa, water is passed through the jacket to cool the polymerization vessel while removing unreacted vinyl chloride monomer, and the resulting resin is washed with deionized water. Then, dehydration and drying were performed to obtain a powdered vinyl chloride resin having a polymerization degree of 640 (chlorine content: 56.8%).
The obtained polyvinyl chloride resin concentration 10 wt% tetrahydrofuran solution (solution E), polymethyl methacrylate (SP value: 9.2 (cal / cm ³ ) ^1/2 ) resin concentration 10 wt% tetrahydrofuran solution (solution F) was prepared, and filtered through an alumina ceramic filter having a pore diameter of 0.05 μm.

Thereafter, while mixing the solution E and the solution F with an instantaneous mixer, supply and drying are repeated using a tube pump in a cylindrical container with an inner diameter of 20 mm that rotates around the central axis, and a cavity with a diameter of 1 mm at the center. An optical fiber preform having a refractive index profile of 20 mm in diameter and 450 mm in length was obtained.
First, the solution E and the solution F are supplied and dried at a ratio of 6: 4, the supply amount of the solution F is gradually decreased, and the solution E is added by the reduced amount and supplied at a final ratio of 8: 2. Dried.
The obtained preform was supplied to a cylindrical heater set at 130 ° C., and the central cavity was heated and stretched while reducing the pressure to obtain an optical fiber having a refractive index distribution with a diameter of 0.6 mm.
The obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Example 3)
Hot water at 70 ° C. was passed through the jacket of the jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, the dehydrated methylene chloride, zirconium tetra-n-butoxide 10% by weight toluene solution and methylaluminoxane 10% by weight toluene solution are sequentially injected through the rubber stopper with a syringe into the autoclave under reduced pressure. A sufficiently dehydrated vinyl chloride monomer was injected, the temperature was adjusted to 20 ° C., and polymerization was performed for 24 hours.

  After the polymerization is completed, unreacted vinyl chloride monomer is discharged from the autoclave, methanol is supplied to inactivate the reaction, and the reaction is taken out from the polymerization vessel. The methanol is removed and the polyvinyl chloride resin is dried under vacuum. It was. The dried polyvinyl chloride resin was dissolved in tetrahydrofuran, dissolved in powdered zeolite, stirred for 1 hour, and filtered through a 0.5 μm PTFT filter. The filtrate was put into methanol with stirring to precipitate a polyvinyl chloride resin, and then the polyvinyl chloride resin was filtered from the methanol. After washing with a large amount of methanol, it was dried to obtain a powdered polyvinyl chloride resin.

  The obtained polyvinyl chloride resin is supplied together with deionized water to a jacketed glass-lined pressure-resistant reactor equipped with a stirrer and stirred to disperse the polyvinyl chloride resin in deionized water with a vacuum pump. Air in the reaction vessel was sucked in, decompressed until it reached -78.4 kPa, and nitrogen gas was supplied until it reached normal pressure. Next, the oxygen in the reaction vessel was removed by suction again with a vacuum pump.

The heated oil was supplied to the jacket and heated to raise the temperature in the reaction vessel to 70 ° C. When the temperature in the reaction vessel reached 70 ° C., chlorine gas began to be supplied, and the chlorination reaction was advanced to 110 ° C. The generated hydrogen chloride concentration in the reaction vessel was measured, the chlorine content of the polyvinyl chloride resin was calculated, and the supply of chlorine gas was stopped when the chlorine content reached 66.0% by weight.
Next, unreacted chlorine gas was removed, and the resulting resin was washed with deionized water, dehydrated and dried to obtain a chlorinated polyvinyl chloride resin having a powdery polymerization degree of 550. The amount of generated hydrogen chloride of this chlorinated polyvinyl chloride resin under heating at 200 ° C. for 30 minutes was 87 ppm.
A 10% by weight tetrahydrofuran solution of the obtained chlorinated polyvinyl chloride resin was prepared, filtered through an alumina ceramic filter having a pore size of 0.05 μm, and then removed by a spray drying method to remove foreign matters. A powdery chlorinated polyvinyl chloride resin was obtained.

Two single-screw extruders and two-layer gold set at 190 ° C. so that the obtained foreign substance-removed chlorinated polyvinyl chloride resin is a core layer having an inner diameter of 18 mm and polymethyl methacrylate is a cladding layer having a thickness of 1 mm. An optical fiber preform having a diameter of 20 mm was obtained by molding using a mold.
The obtained preform was supplied to a cylindrical heater set at 140 ° C. and heated and stretched to obtain an optical fiber having a diameter of 0.6 mm.
The core portion of the obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

  The amount of hydrogen chloride generated in the resin is as follows: 1 g of vinyl chloride resin is supplied to a test tube, sealed with a heat-resistant rubber stopper with a tube, and the test tube is immersed in a 200 ° C. oil bath for 2/3 from below and heated. The gas generated from the test tube is collected with 100 ml of ion exchange water for 30 minutes through the tube, the pH of the ion exchange water is measured 30 minutes after the start of collection, and the pH of the ion exchange water before the start of collection is measured. Calculated from the difference (hereinafter the same).

Example 4
A 50-liter jacketed stainless steel polymerization vessel equipped with a stirrer and a reflux condenser was degassed, and steam was blown from the reflux condenser to raise the temperature inside the polymerization vessel to 80 ° C., and deionization at 50 ° C. 25000 g of water, 300 g of 3% solution partially saponified polyvinyl alcohol, and 150 g of 3% hydroxypropylmethylcellulose were fed. Thereafter, the inside of the reaction vessel was degassed to a water vapor pressure of +0.01 kPa, and 15 kg of vinyl chloride monomer was supplied while stirring. Subsequently, 5 g of t-butylperoxyneodecanoate was supplied into the polymerization vessel, and then the temperature was raised to 62 ° C. to carry out polymerization. When the temperature in the polymerization reactor reached 62 ° C, the operation of the reflux condenser was started, and the temperature in the polymerization vessel was maintained at 62 ° C.

When the pressure in the polymerization vessel drops to 0.8 MPa, water is passed through the jacket to remove the unreacted vinyl chloride monomer while cooling the polymerization vessel, and then the resulting resin is washed with deionized water. Then, dehydration and drying were performed to obtain a powdery vinyl chloride resin having a polymerization degree of 860.
The obtained polyvinyl chloride resin is supplied together with deionized water to a jacketed glass-lined pressure-resistant reactor equipped with a stirrer and stirred to disperse the polyvinyl chloride resin in deionized water with a vacuum pump. Air in the reaction vessel was sucked in, decompressed until it reached -78.4 kPa, and nitrogen gas was supplied until it reached normal pressure. Next, the oxygen in the reaction vessel was removed by suction again with a vacuum pump.

The heated oil was supplied to the jacket and heated to raise the temperature in the reaction vessel to 70 ° C. When the temperature in the reaction vessel reached 70 ° C., chlorine gas began to be supplied, and the chlorination reaction was advanced to 110 ° C. The generated hydrogen chloride concentration in the reaction vessel was measured, the chlorine content of the polyvinyl chloride resin was calculated, and the supply of chlorine gas was stopped when the chlorine content reached 68.0% by weight.
Next, unreacted chlorine gas is removed, and the resulting resin is washed with deionized water, dehydrated and dried to obtain a chlorinated polyvinyl chloride resin having a powdery chlorine content of 68.0% and a polymerization degree of 860. Obtained.
A 10% by weight solution of chlorinated polyvinyl chloride in tetrahydrofuran (solution G) was prepared and filtered through an alumina ceramic filter having a pore size of 0.05 μm.

Thereafter, a cylinder having an inner diameter of 20 mm that rotates around the central axis while mixing the solution G and tri-2-ethylhexyl trimellitic acid (SP value: 8.9 (cal / cm ³ ) ^1/2 ) with an instantaneous mixer. Supply and drying were repeated using a tube pump in a cylindrical container to obtain an optical fiber preform having a refractive index distribution of 20 mm in diameter and 450 mm in length with a hollow portion having a diameter of 1 mm in the center.

First, the solution G and tri-2-ethylhexyl trimellitic acid were supplied and dried at a ratio of 75: 2.5, and the supply amount of tri-2-ethylhexyl trimellitic acid was gradually reduced. Double the amount of solution G was added and fed and dried at a final ratio of 90: 1.
From the periphery to the center, the trimellitic acid tri-2-ethylhexyl compounding ratio (% by weight) is changed from 25 to 10, and the conversion degree of polymerization is changed from 570 to 740.
The obtained preform was supplied to a cylindrical heater set at 110 ° C., and the central cavity was heated and stretched while reducing the pressure to obtain an optical fiber having a refractive index distribution with a diameter of 0.6 mm.
The obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Example 5)
Hot water at 70 ° C. was passed through the jacket of the jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, inject the dehydrated methylene chloride, zirconium tetra-n-butoxide 10 wt% toluene solution and methylaluminoxane 10 wt% toluene solution into the autoclave under reduced pressure with a syringe through a rubber stopper. The dehydrated vinyl chloride monomer was injected into the solution, and the temperature was adjusted to 20 ° C. and polymerized for 48 hours.

  After the polymerization was completed, the unreacted vinyl chloride monomer was discharged from the autoclave, the reaction was deactivated by supplying methanol, and then removed from the polymerization vessel. The methanol was removed and the polyvinyl chloride resin was dried under vacuum. . The dried polyvinyl chloride resin was dissolved in tetrahydrofuran, dissolved in zeolite, and stirred for 1 hour, and then filtered through a 0.5 μm PTFT filter. The filtrate was put into methanol with stirring to precipitate a polyvinyl chloride resin. The polyvinyl chloride resin was separated from the methanol by filtration, washed with a large amount of methanol, and dried to obtain a powdery polyvinyl chloride resin.

  The obtained polyvinyl chloride resin is supplied together with deionized water to a jacketed glass-lined pressure-resistant reactor equipped with a stirrer and stirred to disperse the polyvinyl chloride resin in deionized water with a vacuum pump. Air in the reaction vessel was sucked in, decompressed until it reached -78.4 kPa, and nitrogen gas was supplied until it reached normal pressure. Next, the oxygen in the reaction vessel was removed by suction again with a vacuum pump.

The heated oil was supplied to the jacket and heated to raise the temperature in the reaction vessel to 70 ° C. When the temperature in the reaction vessel reached 70 ° C., chlorine gas began to be supplied, and the chlorination reaction was advanced to 110 ° C. The generated hydrogen chloride concentration in the reaction vessel was measured, the chlorine content of the polyvinyl chloride resin was calculated, and the supply of chlorine gas was stopped when the chlorine content reached 67.7% by weight.
Next, unreacted chlorine gas was removed, and the resulting resin was washed with deionized water, dehydrated and dried to obtain a powdery chlorinated polyvinyl chloride resin having a degree of polymerization of 730. The amount of generated hydrogen chloride of this chlorinated polyvinyl chloride tree under heating at 200 ° C. for 30 minutes was 76 ppm.

A tetrahydrofuran solution containing 8% by weight of the obtained chlorinated polyvinyl chloride resin and 2% by weight of triisodecyl trimellitic acid (SP value: 8.4 (cal / cm ³ ) ^1/2 ) was prepared. After filtering through a 0.05 μm alumina ceramic filter, a powdery chlorinated polyvinyl chloride resin composition was obtained by removing the solvent by spray drying to remove foreign matter.
Two single-screw extruders set at 190 ° C. so that the foreign substance-removed chlorinated polyvinyl chloride resin composition is a core layer having an inner diameter of 18 mm and polymethyl methacrylate is a cladding layer having a thickness of 1 mm; An optical fiber preform having a diameter of 20 mm, a core layer having a triisodecyl trimellitic acid compounding ratio of 20% by weight, and a conversion degree of polymerization of 530 was obtained using a two-layer mold.

The obtained preform was supplied to a cylindrical heater set at 140 ° C. and heated and stretched to obtain an optical fiber having a diameter of 0.6 mm.
The core portion of the obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Example 6)
A tetrahydrofuran solution (solution G) having a resin concentration of 10% by weight of chlorinated polyvinyl chloride obtained in Example 4 was prepared, and filtered through an alumina ceramic filter having a pore diameter of 0.05 μm.
Then, while dissolving triphenyl phosphate (SP value: 8.6 (cal / cm ³ ) ^1/2 ) in the solution G, a tube pump was used in a cylindrical container with an inner diameter of 20 mm that rotated around the central axis. The supply and drying were repeated to obtain an optical fiber preform having a refractive index profile of 20 mm in diameter and 450 mm in length with a hollow portion having a diameter of 1 mm in the center.

First, the solution G and triphenyl phosphate are supplied and dried at a ratio of 90: 1, the supply amount of the solution G is gradually decreased, and triphenyl phosphate is added by 1/10 of the reduced amount to obtain a final 75. : Supplied and dried at a ratio of 2.5.
From the peripheral part to the central part, the triphenyl phosphate blending ratio changes from 10 to 25% by weight, and the conversion degree of polymerization changes from 740 to 570.
The obtained preform was supplied to a cylindrical heater set at 110 ° C., and the central cavity was heated and stretched while reducing the pressure to obtain an optical fiber having a refractive index distribution with a diameter of 0.6 mm.
The obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Example 7)
A 50-liter jacketed stainless steel polymerization vessel equipped with a stirrer and a reflux condenser was degassed, and then steam was blown from the reflux condenser to raise the temperature inside the polymerization vessel to 80 ° C., and deionization at 50 ° C. 25000 g of water, 300 g of 3% solution partially saponified polyvinyl alcohol, and 150 g of 3% hydroxypropylmethylcellulose were fed. Thereafter, the inside of the reaction vessel was deaerated to a water vapor pressure of +0.01 kPa, and then 15 kg of vinyl chloride monomer was supplied while stirring. Next, 5 g of t-butyl peroxypivalate was supplied into the polymerization vessel, and then the temperature was raised to 69 ° C. to carry out polymerization. When the temperature in the polymerization vessel reached 69 ° C, the operation of the reflux condenser was started, and the temperature in the polymerization vessel was maintained at 69 ° C.

When the pressure in the polymerization vessel drops to 0.9 MPa, water is passed through the jacket to cool the polymerization vessel while removing unreacted vinyl chloride monomer, and the resulting resin is washed with deionized water. Then, dehydration and drying were performed to obtain a powdered vinyl chloride resin having a polymerization degree of 690.
The obtained polyvinyl chloride resin is supplied together with deionized water to a jacketed glass-lined pressure-resistant reactor equipped with a stirrer and stirred to disperse the polyvinyl chloride resin in deionized water with a vacuum pump. Air in the reaction vessel was sucked in, decompressed until it reached -78.4 kPa, and nitrogen gas was supplied until it reached normal pressure. Next, the oxygen in the reaction vessel was removed by suction again with a vacuum pump.

The heated oil was supplied to the jacket and heated to raise the temperature in the reaction vessel to 70 ° C. When the temperature in the reaction vessel reached 70 ° C., chlorine gas began to be supplied, and the chlorination reaction was advanced to 110 ° C. The generated hydrogen chloride concentration in the reaction vessel was measured, the chlorine content of the polyvinyl chloride resin was calculated, and the supply of chlorine gas was stopped when the chlorine content reached 63.8% by weight.
Next, unreacted chlorine gas is removed, and the resulting resin is washed with deionized water, dehydrated and dried to obtain a chlorinated polyvinyl chloride resin having a powdery chlorine content of 63.8% and a polymerization degree of 690. Obtained.
A tetrahydrofuran solution containing 8.3% by weight of the obtained chlorinated polyvinyl chloride and 1.7% by weight of diphenylsulfone was prepared, filtered through an alumina ceramic filter having a pore diameter of 0.05 μm, and then spray dried. A powdery chlorinated polyvinyl chloride resin composition from which foreign matter was removed by removing the solvent was obtained.

The obtained foreign substance-removed chlorinated polyvinyl chloride resin composition was formed into two single units set at 150 ° C. and 190 ° C., respectively, so as to form a core layer having an inner diameter of 18 mm and polymethyl methacrylate as a cladding layer having a thickness of 1 mm. An optical fiber preform having a diameter of 20 mm, a diphenylsulfone compounding ratio of the core layer of 17% by weight, and a conversion degree of polymerization of 530 was obtained by molding using a shaft extruder and a two-layer mold.
The obtained preform was supplied to a cylindrical heater set at 90 ° C., and heated and stretched to obtain an optical fiber having a diameter of 0.6 mm.
The core portion of the obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Example 8)
Hot water at 70 ° C. was passed through the jacket of the jacketed autoclave, the inside of the autoclave was decompressed with a vacuum pump for 30 minutes, sufficiently dehydrated and dried, and then cooled to room temperature. After cooling, dehydrated methylene chloride and 1.6 mol% n-pentane solution of t-butyllithium are sequentially injected through a rubber stopper with a syringe into an autoclave under reduced pressure, and further vinyl chloride sufficiently dehydrated with molecular sieves. The monomer was injected, the temperature was adjusted to 20 ° C., and polymerization was performed for 24 hours.

  After completion of the polymerization, unreacted vinyl chloride monomer was discharged from the autoclave, and methanol was supplied to deactivate the reaction. Then, it removed from the superposition | polymerization device, methanol was removed, and the polyvinyl chloride resin part was dried under vacuum. The dried polyvinyl chloride resin was dissolved in tetrahydrofuran and then filtered through a 0.5 μm PTFT filter. The filtrate was put into methanol with stirring to precipitate a polyvinyl chloride resin, and then the polyvinyl chloride resin was filtered from the methanol. After washing with a large amount of methanol, it was dried to obtain a powdered polyvinyl chloride resin.

  The obtained polyvinyl chloride resin is supplied together with deionized water to a jacketed glass-lined pressure-resistant reactor equipped with a stirrer and stirred to disperse the polyvinyl chloride resin in deionized water with a vacuum pump. Air in the reaction vessel was sucked in, decompressed until it reached -78.4 kPa, and nitrogen gas was supplied until it reached normal pressure. Subsequently, it was again sucked with a vacuum pump to remove oxygen in the reaction vessel.

The heated oil was supplied to the jacket and heated to raise the temperature in the reaction vessel to 70 ° C. When the temperature in the reaction vessel reached 70 ° C., chlorine gas began to be supplied, and the chlorination reaction was advanced to 110 ° C. The generated hydrogen chloride concentration in the reaction vessel was measured, the chlorine content of the polyvinyl chloride resin was calculated, and the supply of chlorine gas was stopped when the chlorine content reached 66.0% by weight.
Next, unreacted chlorine gas was removed, and the resulting resin was washed with deionized water, dehydrated and dried to obtain a powdery chlorinated polyvinyl chloride resin having a polymerization degree of 670. The amount of hydrogen chloride generated by heating this chlorinated polyvinyl chloride resin at 200 ° C. for 30 minutes was 128 ppm.

A tetrahydrofuran solution containing 8.5% by weight of the obtained chlorinated polyvinyl chloride resin and 1.5% by weight of tri-2-ethylhexyl trimellitic acid (SP value: 8.9 (cal / cm ³ ) ^1/2 ) was prepared. It produced and filtered with the filter made from an alumina ceramic with a pore diameter of 0.05 micrometer. Then, a powdery chlorinated polyvinyl chloride resin composition from which foreign matter was removed by removing the solvent by spray drying was obtained.
Two single-screw extruders set at 190 ° C. so that the obtained foreign substance-removed chlorinated polyvinyl chloride resin composition has a core layer with an inner diameter of 18 mm and a polymethyl methacrylate clad layer with a thickness of 1 mm, and 2 An optical fiber preform having a diameter of 20 mm, a blending ratio of tri-2-ethylhexyl trimellitic acid in the core layer of 15% by weight, and a conversion degree of polymerization of 530 was obtained using a layer mold.

The obtained preform was supplied to a cylindrical heater set at 140 ° C. and heated and stretched to obtain an optical fiber having a diameter of 0.6 mm.
The core portion of the obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

Example 9
A tetrahydrofuran solution (solution G) having a resin concentration of 10% by weight of chlorinated polyvinyl chloride obtained in Example 4 was prepared, and filtered through an alumina ceramic filter having a pore diameter of 0.05 μm.
Thereafter, triphenyl phosphate and dipentaerystol ester UL-6 (SP value: 8.6 (cal / cm ³ ) ^1/2 ) manufactured by Asahi Denka Co., Ltd. were added to solution G and (amount of triphenyl phosphate and UL-6). While being dissolved in the solution G so that the sum is 75: 2.5, it is repeatedly supplied and dried using a tube pump into a cylindrical container with an inner diameter of 20 mm that rotates around the central axis. An optical fiber preform having a refractive index profile of 450 mm was obtained.

  In addition, the ratio of triphenyl phosphate and UL-6 at the time of blending is that UL-6 is first supplied and dried at a ratio of 100, the amount of UL-6 is gradually decreased, and triphenyl phosphate is added by the reduced amount. The final triphenyl phosphate was supplied and dried at a ratio of 100. A preform having a composition distribution in which UL-6 gradually decreased from the peripheral part toward the central part and conversely triphenyl phosphate increased was obtained.

The obtained preform was supplied to a cylindrical heater set at 110 ° C., and the central cavity was heated and stretched while reducing the pressure to obtain an optical fiber having a refractive index distribution with a diameter of 0.6 mm.
The obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Comparative Example 1)
A 10% by weight tetrahydrofuran solution (solution E) of polyvinyl chloride having a chlorine content of 56.8% and a polymerization degree of 640 obtained in Example 2 was prepared and filtered through an alumina ceramic filter having a pore size of 0.05 μm. Went.
Thereafter, the solution E is repeatedly supplied and dried using a tube pump in a cylindrical container having an inner diameter of 20 mm that rotates around the central axis, and an optical fiber having a diameter of 20 mm and a length of 450 mm having a hollow portion with a diameter of 1 mm at the center. A preform was obtained.
The obtained preform was supplied to a cylindrical heater set at 130 ° C. and heated and stretched while reducing the central cavity to obtain an optical fiber having a diameter of 0.6 mm.
The obtained optical fiber was cut out and evaluated in the same manner as in Example 1.

(Comparative Example 2)
A plurality of tetrahydrofuran solutions containing 7% by weight of the chlorinated polyvinyl chloride resin obtained in Example 5 and 2.5 to 3% by weight of triisodecyl trimellitic acid were prepared, and an optical fiber was produced in the same manner as in Example 5. As the blending ratio (% by weight) of trimisolic trimellitic acid in the core layer increased from 26 to 30, plastic deformation gradually occurred.

(Comparative Example 3)
A plurality of tetrahydrofuran solutions containing 7% by weight of chlorinated polyvinyl chloride obtained in Example 7 and 2.5 to 3% by weight of diphenylsulfone were prepared, and an optical fiber was produced in the same manner as in Example 7. As the diphenylsulfone blending ratio (% by weight) increased from 26 to 30, plastic deformation was apt to occur gradually.

The present invention can be used in any field where the use of a vinyl chloride resin is expected. In particular, it is useful in the field of high transparency. For example, it is useful as a component of various optical devices such as optical systems, specifically optical fibers, optical fiber preforms, various lenses such as rod lenses, optical waveguides, etc. is there.

Claims (3)

A compound selected from diphenylsulfone and its derivatives is blended with a resin composition mainly composed of a polyvinyl chloride resin having a chlorine content of 62% or more and 73% or less,
Compound selected from the diphenyl sulfone and its derivatives Ri der than 25 wt%, and diphenyl sulfone derivative is 4,4'-dichlorodiphenyl sulfone and 3,3 ', 4,4'-tetrachloro diphenyl sulfone At least Tsudea Ru optical transmission member selected from the group consisting of.   The optical transmission body according to claim 1, comprising a resin composition containing as a main component a polyvinyl chloride resin having an amount of generated hydrogen chloride of 150 ppm or less under heating at 200 ° C. for 30 minutes.   The optical transmission body according to claim 1 or 2, having a refractive index distribution.