JPH09324319A - Transparent fiber and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transparent fiber having excellent high-temperature strength and light-transmitting properties and useful for a core material of optical fiber, etc., by melt-spinning a copolymer containing an acrylic monomer, etc., and polymerizable monomer having alkoxysilyl group and curing the fiber with moisture. SOLUTION: This transparent fiber having a glass transition temperature of >=110 deg.C, a yield point of >=50kgf/cm<2> at 110 deg.C and a breakage strength of >=90kgf/cm<2> is produced by crosslinking a copolymer containing an acrylic and/or styrene-based monomer and a polymerizable monomer having an alkoxysilyl group as essential monomer units and having recurring units of formula I [R<1> is H or methyl; R<2> is COOR<4> (R<4> is a 1-6C chain alkyl, etc.), phenyl or CN] and formula II (R<3> is direct bond, etc.; R<6> is H or a 1-5C alkyl; R<7> is H, an alkyl, etc.; (a) is 0 or 1) with a siloxane bond, melt-spinning the produced copolymer having crosslinked structure and curing the spun fiber with moister in an atmosphere of 20-100 deg.C and a relative humidity of 40-100%RH.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a transparent fiber which contains a (meth) acrylic and / or styrenic monomer and an alkoxyl group-containing polymerizable monomer as essential monomer units and is excellent in heat resistance and light transmission properties, and Regarding a method that can efficiently produce transparent fiber by a simple method, the transparent fiber obtained by this method takes advantage of its excellent light transmittance and heat resistance, and can be used for optical transmission represented by, for example, a core material of an optical fiber. It can be effectively used as an optical fiber material for the body and the like.

[0002]

2. Description of the Related Art Fibers containing (meth) acrylic polymers and styrene polymers as main components have excellent light-transmitting properties, and also have good moldability, impact resistance, and economical efficiency. Therefore, it is widely used as an optical material and the like. Among them, polymethylmethacrylate is transparent,
It is also very excellent in mechanical properties and light resistance, and has been put to practical use as an optical fiber for illumination and communication.

However, these materials generally have poor heat resistance, and the strength of the materials is extremely lowered near the glass transition temperature of the resin material to cause deformation, which makes them unsuitable for applications exposed to high temperature conditions. Therefore, the following methods have been proposed to improve heat resistance, but the following problems are pointed out.

A method in which an appropriate amount of a polyfunctional monomer is used in combination with a (meth) acrylic monomer to cause a crosslinking reaction during polymerization (JP-A-57-45502). In this method, since three-dimensional cross-linking is formed during polymerization, it is not possible to employ a method of softening by heat such as melt spinning to form a molded article, and in order to obtain a rod-shaped or fiber-shaped molded article, The polymerization reaction must be carried out in a hollow tube having a size corresponding to the shape, resulting in extremely low productivity.

A method of causing a crosslinked structure by irradiating an electron beam or radiation to increase the production amount of free radicals. This method requires special technology and expensive equipment, which not only makes the product very expensive, but also deteriorates the polymer due to the irradiation of electron beams and radiation, which adversely affects the physical properties and light transmittance. Appears.

[0006]

The present invention has been made in view of the above circumstances, and an object thereof is to provide a transparent fiber having both excellent light transmission characteristics and heat resistance. Aims to establish a technique capable of efficiently producing the transparent fiber by a relatively simple method.

[0007]

Means for Solving the Problems The production method of the present invention which has been able to solve the above-mentioned problems is to provide a copolymer containing a (meth) acrylic and / or styrenic monomer and an alkoxysilyl group-containing polymerizable monomer as essential monomer units. The characteristic is that it is subjected to wet spinning after melt spinning. The preferred wet curing conditions employed when carrying out this method are in the temperature range of 20 to 100 ° C. and relative humidity of 40 to 100%, and according to this method, the glass transition temperature is 110.
Yield point is 50kgf / cm ^{2 at} ℃ above 110 ℃
As described above, it is possible to obtain a transparent fiber having a very high performance in terms of optical strength and mechanical properties, such as a breaking strength of 90 kgf / cm ² or more.

Further, the transparent fiber of the present invention has novel structural characteristics in the chemical structure of the resin component, which is the main component, because of the characteristic of the manufacturing method, as compared with the transparent fiber obtained by the conventional method. The resin component has a structure in which a copolymer having repeating units represented by the following formulas X and Y is crosslinked by a siloxane bond in the molecular chain, and has a glass transition temperature of 110 ° C. or higher and a yield point at 110 ° C. Of 50 kgf / cm ² or more, breaking strength of 90 k
When it is at least gf / cm ² , it can be positioned as a new transparent fiber in that it can be clearly differentiated from the conventional transparent fiber.

[0009]

Embedded image

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, in the manufacturing method of the present invention,
A thermoplastic and spinnable copolymer is produced by using a (meth) acrylic and / or styrene-based monomer and an alkoxysilyl group-containing polymerizable monomer as essential monomer units, and the polymer is melt-spun to be fibrous. After being molded into, the cross-linking and curing is carried out by a wet method by utilizing the reaction activity of the alkoxysilyl group contained in the copolymer with water to obtain a transparent fiber having an improved heat resistance.

That is, in the means for improving the heat resistance of the transparent fiber which has been carried out so far, a crosslinking reaction is caused at the time of producing the polymer constituting the fiber as mentioned above, and the crosslinking reaction causes the polymer to become thermoplastic. Cannot be formed into a fibrous shape by the melt-spinning method because the melting point is lost or the melting temperature is significantly increased. Therefore, the cross-linking reaction must be carried out in the hollow tube having a size corresponding to the target wire diameter as described above, resulting in extremely low productivity.

On the other hand, in the method of the present invention, as described above, first, a thermoplastic polymer containing a polymerization-reactive monomer having an alkoxysilyl group as a reactive functional group in the molecule as an essential monomer unit is prepared. The melt-spinning method is used to form a fibrous product, which is then subjected to a wet treatment to allow the alkoxysilyl group in the polymer molecule to undergo a dealcohol cross-linking reaction in the presence of water. As a result, it becomes possible to extremely efficiently produce a transparent fiber having a heat resistance enhanced by a crosslinked structure by a simple treatment. The history of such a procedure is shown below by a typical reaction formula.

[0013]

Embedded image

The (meth) acrylic monomers used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylate. Acrylic acid n-
Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth) ) Cyclohexyl acrylate, (meth) acrylic acid esters such as 2-hydroxyethyl (meth) acrylate, and (meth) acrylonitrile are exemplified, and these may be used alone or, if necessary, two or more kinds. Can be used together. Typical examples of the styrene-based monomer include aromatic vinyl compounds such as styrene and α-methylstyrene.
More than one species can be used. Next, examples of the polymerizable monomer having an alkoxysilyl group include polymerizable silane compounds represented by the following formulas A, B and C.

[0015]

Embedded image

(However, in the above formulas A, B and C, R ¹ is a hydrogen atom or a methyl group, R ⁸ is an alkylene group having 1 to 6 carbon atoms, R ⁹ is a hydrogen atom or a substituted group having 1 to 5 carbon atoms. Optionally an alkyl group, R ¹⁰ is a hydrogen atom or an optionally substituted group selected from an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group and an acyl group, and s,
t and u are each independently an integer of 0 or 1, and a plurality of R ^{9 s in} one molecule may be the same or different.

Preferred specific examples of the polymerizable silane compound represented by the above formula A include γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane and γ- (meth) acryl. Examples thereof include (meth) acryloxy-based alkoxysilanes such as roxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, and γ- (meth) acryloxypropylphenyldimethoxysilane. Polysiloxane macromonomer having a (meth) acryloyl group as shown in

[0018]

Embedded image Etc. are illustrated.

Preferred specific examples of the polymerizable silane compound represented by the above formula B include vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane and the like, and preferred specific examples of the polymerizable silane compound represented by the above formula C. Examples include 1-hexenyltrimethoxysilane, 1-octenyltrimethoxysilane, vinyloxypropyltrimethoxysilane, 3-vinylphenyltrimethoxysilane, 3- (vinylbenzylaminopropyl) trimethoxysilane and the like. .

These polymerizable silane compounds represented by the formulas A to D may be used alone or, if necessary, may be used in combination of two or more kinds as appropriate. The above formulas A to D
Among the polymerizable silane compounds represented by, s, t, u, v
Is preferably 0 because a copolymer having high wet-curing reactivity is easily obtained, and when R ⁹ is an alkyl group having 1 to 3 carbon atoms, especially a methyl group, R ⁹ is formed during the wet-curing reaction. It is preferable in that the alcohol to be removed can be removed from the system more quickly. In addition, the polysiloxane macromonomer represented by the above formula D has a large number of cross-linking points per molecule, and therefore intermolecular cross-linking easily occurs, and as a result, the heat resistance of the fiber can be improved relatively easily. Recommended as a compound.

In the above, the (meth) acrylic monomer and / or styrene monomer imparts essential mechanical properties and light transmission properties as a main component of the finally obtained transparent fiber, and at the same time, melt-spinability before wet treatment. The alkoxysilyl group-containing polymerizable monomer (polymerizable silane compound), on the other hand, introduces an alkoxysilyl group into the copolymer to impart wet-curing characteristics to the copolymer, and finally gives a transparent product. It exerts the function of enhancing the strength characteristics of fibers, especially the heat resistance strength characteristics. And, in order to effectively exhibit the characteristics of these (meth) acrylic monomer and / or styrene monomer and the alkoxysilyl group-containing polymerizable monomer, the (meth) acrylic monomer and / or styrene monomer: polymerizable silane compound The copolymerization ratio is 50-99: 50-1 by weight, more preferably 60-95: 40-5, still more preferably 7.
It is desirable to set in the range of 0 to 90:30 to 10.

At this time, if the copolymerization ratio of the (meth) acrylic monomer and / or styrene monomer is less than 50% by weight, moldability, impact resistance, economical efficiency, etc. may be impaired, and conversely 99% by weight. If the amount is excessively higher than 0.1%, the copolymerization ratio of the polymerizable silane compound becomes relatively small, and it becomes difficult to sufficiently increase the crosslink density when wet-curing after melt spinning, and the transparent fiber finally obtained. There is a tendency for the heat resistance of the product to become insufficient.

The essential polymerizable monomers used in the present invention are as described above, but if necessary, other copolymerizable monomers such as N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide and the like can be used. It is also possible to copolymerize an appropriate amount of N-substituted maleimides, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, and vinyl compounds such as maleic anhydride and vinyl acetate. The usage ratio of these other copolymerizable monomers is
It should be appropriately set according to the degree of modification properties expected of the monomer, but it is polymerized with the (meth) acrylic monomer and / or styrene monomer so as not to impair the properties of the essential monomer. It is desirable to control the amount of the organic silane compounds to about 30% by weight or less, more preferably 20% by weight or less.

The polymerization method using the above-mentioned monomer components is not particularly limited, and lauroyl peroxide,
Organic peroxides such as benzoyl peroxide, α,
A radical initiator such as an azo compound such as α'-azobisisobutyronitrile is used, and usually from room temperature to 150 ° C.
It may be carried out under the temperature condition of. Depending on the case,
It is also possible to use a small amount of reducing agent together as a redox catalyst, or to adopt a photopolymerization method using a photopolymerization initiator or a photosensitizer such as benzophenone, acetophenone, benzoin methyl ether, and benzoin isobutyl ether. is there.

The copolymer obtained by copolymerizing the above-mentioned copolymerizable monomers is a chain polymer having substantially no cross-linking structure and has a softening point of 5 depending on its molecular weight.
It is a thermoplastic resin having a temperature of about 0 to 120 ° C., and can be continuously formed into fibers by melt spinning in a usual manner. Moreover, an alkoxysilyl group derived from the polymerizable silane compound has been introduced into the polymer, and therefore, when this is wet treated after melt spinning,
For example, as shown in the above reaction formula, an intermolecular cross-linking reaction occurs to harden the glass transition point, and a glass transition point is rapidly increased, or a highly heat-resistant transparent fiber having substantially no glass transition point is obtained.

The treatment conditions for the wet curing are not particularly limited, but from the viewpoint of uniformly promoting the curing reaction, an atmosphere of about 20 to 100 ° C. and a relative humidity of about 40 to 100% is preferable, and 1 to 100 is preferable. It is a method of treating for about 3 to 30 hours. After the wet curing, it is preferable to volatilize and remove the alcohol component produced by the curing reaction at 20 to 120 ° C. under normal pressure or reduced pressure. In any case, during this wet curing reaction, excessive heat is not applied to the melt-spun copolymer, so that the deterioration or alteration of the copolymer as pointed out in the prior art does not occur, and therefore the curing is not performed. It is possible to obtain an optical fiber having high heat resistance while maintaining excellent transparency without fear of impairing transparency due to the treatment.

The transparent fiber of the present invention thus obtained is the same as the transparent fiber obtained by the conventional method.
Due to the characteristics of the above-mentioned manufacturing method, the resin component, which is the main component, also has a novel structural characteristic, and the resin component has repeating units represented by the following formulas X and Y in the molecular chain. The copolymer has a structure in which it is crosslinked by a siloxane bond, so that it can be clearly differentiated from the conventional transparent fiber, and its physical property is that the glass transition temperature is 110 ° C or higher and the yield point at 110 ° C. Is 50 kgf / cm ² or more, breaking strength is 90 kgf / cm
^It has excellent properties such as ² or more in terms of physical properties compared to conventional transparent fibers.

[0028]

[Chemical 6]

In carrying out the present invention, it is also possible to introduce bromobenzene, phenyl sulfide or the like as a refractive index adjusting component of the obtained fiber into the thermoplastic polymer obtained by the above copolymerization. A method in which a small amount is blended before or after the copolymerization and then melt spinning is recommended.

The transparent fiber thus obtained has a high light transmission property, is imparted with a high level of heat resistance by a wet crosslinking reaction, and is also very excellent in strength property. By properly selecting the type and combination of (meth) acrylic and / or styrene type monomer and the alkoxysilyl group-containing polymerizable monomer, the copolymerization ratio, etc., for example, the glass transition temperature is 110 ° C. or higher and the yield point at 110 ° C. 50 kgf /
cm ² or more, the breaking strength is optically transparent highly transparent fiber having a characteristic such 90 kgf / cm ² or more.

This transparent fiber can be put to practical use as it is depending on the application, but when it is used as an optical fiber, for example, a polymer having a smaller optical refractive index than the transparent fiber on the outer peripheral side of the transparent fiber. A clad layer made of (or a copolymer) may be formed, and the outer periphery of the clad layer may be covered with an appropriate exterior material for practical use. The material of the clad layer used here is a polymer or copolymer of (meth) acrylic acid fluorinated ester such as (meth) acrylic acid trifluoroethyl, (meth) acrylic acid tetrafluoropropyl, or the like. Copolymers of (meth) acrylic acid ester are exemplified as preferable ones. For forming these clad layers, a conventionally known method can be adopted,
For example, a method of coating the fiber of the present invention obtained by wet curing with the above-mentioned monomer which is a raw material for the clad layer, and then polymerizing the fiber by irradiating heat or light energy, or a fiber of the present invention for forming a clad layer The method of dipping and traveling in the solution or melt may be adopted.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention is not limited thereto. Modifications may be made and all of them are included in the technical scope of the present invention. still,
The physical property test methods adopted in the following examples are as follows.

(Glass transition point measuring method) It is measured using a differential scanning calorimeter ("DSC220C" manufactured by Seiko Instruments Inc.). (Fiber Tensile Test Method) A tensile tester equipped with a thermostatic chamber (“Autograph AGS100D” manufactured by Shimadzu Corporation) is used to perform a tensile test in an atmosphere of 110 ° C. to measure the yield point and breaking strength of the fiber. . The measurement conditions were such that both ends of the fiber were fixed so that the chuck distance was 40 mm, and the crosshead speed was 50 mm / min.

(Measurement of Transparency) It was confirmed visually from the side of the fiber that it was transparent, and one end of the fiber of 1 m was directed to a white light source, and white light was transmitted from the other end. Check visually. The white light was confirmed to be transmitted, and the non-transmissive light was indicated to be x.

Example 1 In a glass test tube, 90 parts by weight of methyl methacrylate (MMA), 10 parts by weight of γ-methacryloxypropyltrimethoxysilane (MPTMS), 0.15 parts by weight of n-butyl mercaptan and 0 of lauriloyl peroxide were placed. .5
Part by weight was charged and the tube was sealed. Polymerization was carried out by immersing it in an oil bath adjusted to 70 ° C. for 17 hours, and after completion of the polymerization, the outer test tube was broken and removed to obtain a rod-shaped resin having a diameter of 7.5 mm. This rod-shaped resin was melt-spun while being indirectly heated in a cylindrical heating cylinder set at 280 ° C. to have a diameter of 1
mm of thermoplastic resin fiber a was obtained.

This fiber was heated at a temperature of 60 ° C. and a humidity of 90.
It is inserted into a thermo-hygrostat set to% RH, left for 20 hours for wet crosslinking, and then dried for 2 hours in a vacuum dryer set at 70 ° C × 40 mmHg for 2 hours to improve transparency. Fiber A was obtained. In the above, the physical properties of the thermoplastic resin fiber a before wet crosslinking are shown in Table 1 below, and the physical properties and transparency of the finally obtained transparent fiber A are shown in Table 2 below.

Example 2 The ratio of the copolymerizable monomer used was 8% by weight of methyl methacrylate.
Resin fiber b before wet curing was obtained in exactly the same manner as in Example 1 except that 0 parts by weight and 20 parts by weight of γ-methacryloxypropyltrimethoxysilane were used, and wet crosslinking was performed in the same manner as in Example 1. And it dried and the transparent fiber B was obtained. The physical properties of the thermoplastic resin fiber b before wet crosslinking are shown in Table 1 below, and the physical properties and transparency of the finally obtained transparent fiber B are shown in Table 2 below.

Example 3 The ratio of the copolymerizable monomer used was methyl methacrylate 7
Resin fiber c before wet curing was obtained in the same manner as in Example 1 except that 0 part by weight and 30 parts by weight of γ-methacryloxypropyltrimethoxysilane were used, and wet crosslinking was performed in the same manner as in Example 1. And it dried and the transparent fiber C was obtained. The physical properties of the thermoplastic resin fiber c before wet crosslinking are shown in Table 1 below, and the physical properties and transparency of the finally obtained transparent fiber C are shown in Table 2 below.

Example 4 90 parts by weight of styrene (St) and γ-methacryloxypropyltrimethoxysilane (MPTM) in a glass test tube.
S) 10 parts by weight, n-butyl mercaptan 0.05 parts by weight, and lauroyl peroxide 0.5 parts by weight were charged and the tube was sealed. Polymerization was carried out by immersing it in an oil bath adjusted to 70 ° C. for 72 hours, and after the polymerization was completed, the outer test tube was broken and removed to obtain a rod-shaped resin having a diameter of 7.5 mm. This rod-shaped resin was melt-spun while being indirectly heated in a cylindrical heating cylinder set at 280 ° C. to obtain a thermoplastic resin fiber d having a diameter of 1 mm.

This fiber is heated at a temperature of 60 ° C. and a humidity of 90.
It is inserted into a thermo-hygrostat set to% RH, left for 20 hours for wet crosslinking, and then dried for 2 hours in a vacuum dryer set at 70 ° C × 40 mmHg for 2 hours to improve transparency. Fiber D was obtained. In the above, the physical properties of the thermoplastic resin fiber d before wet crosslinking are shown in Table 1 below, and the physical properties and transparency of the finally obtained transparent fiber D are shown in Table 2 below.

Example 5 The ratio of the copolymerizable monomer used was 80 parts by weight of styrene,
Resin fiber e before wet curing was obtained in the same manner as in Example 4 except that 20 parts by weight of γ-methacryloxypropyltrimethoxysilane was used, and wet crosslinking and drying were performed in the same manner as in Example 1. And transparent fiber E
I got The physical properties of the thermoplastic resin fiber e before wet crosslinking are shown in Table 1 below, and the physical properties and transparency of the finally obtained transparent fiber E are shown in Table 2 below.

Example 6 The ratio of the copolymerizable monomer used was 70 parts by weight of styrene,
Resin fiber f before wet curing was obtained in the same manner as in Example 4 except that 30 parts by weight of γ-methacryloxypropyltrimethoxysilane was used, and wet crosslinking and drying were performed in the same manner as in Example 1. And transparent fiber F
I got The physical properties of the thermoplastic resin fiber f before wet crosslinking are shown in Table 1 below, and the physical properties and transparency of the finally obtained transparent fiber F are shown in Table 2 below.

Comparative Example 1 100 parts by weight of methyl methacrylate, n in a glass test tube
-Butyl mercaptan (0.15 parts by weight) and lauroyl peroxide (0.5 parts by weight) were charged and the tube was sealed. Polymerization was carried out by immersing it in an oil bath adjusted to 70 ° C. for 17 hours, and after completion of the polymerization, the outer test tube was broken and removed to obtain a rod-shaped resin having a diameter of 7.5 mm. This rod-shaped resin was melt-spun while being indirectly heated in a cylindrical heating cylinder set at 280 ° C. to obtain a thermoplastic resin fiber g having a diameter of 1 mm. The physical properties of the thermoplastic resin fiber g are shown in Table 1 below. The alkoxysilyl group was not introduced into the molecule of the resin fiber, and the resin fiber had no wet crosslinking reactivity, so that the wet treatment was not performed.

Comparative Example 2 A glass test tube was charged with 100 parts by weight of styrene, 0.05 part by weight of n-butyl mercaptan and 0.5 part by weight of lauriloyl peroxide, and the tube was sealed. Polymerization was carried out by immersing it in an oil bath adjusted to 70 ° C. for 72 hours, and after the polymerization was completed, the outer test tube was broken and removed to obtain a rod-shaped resin having a diameter of 7.5 mm. 280 this rod-shaped resin
Melt-spinning was performed while indirectly heating in a cylindrical heating cylinder set to ° C to obtain a thermoplastic resin fiber h having a diameter of 1 mm.
The physical properties of the thermoplastic resin fiber h are shown in Table 1 below.
Since no alkoxysilyl group was introduced into the molecule of the resin fiber and it had no wet crosslinking reactivity, no wet treatment was carried out.

Comparative Example 3 A glass test tube was charged with 100 parts by weight of γ-methacryloxypropyltrimethoxysilane (MPTMS), 0.15 parts by weight of n-butyl mercaptan and 0.5 parts by weight of lauriloyl peroxide and sealed. . Polymerization was carried out by immersing it in an oil bath adjusted to 70 ° C. for 17 hours, and after completion of the polymerization, the outer test tube was broken and removed to obtain a rod-shaped resin having a diameter of 7.5 mm. This rod-shaped resin is
Melt-spinning was performed while indirectly heating in a cylindrical heating cylinder set to ° C to obtain a thermoplastic resin fiber i having a diameter of 1 mm.

This fiber i is treated at a temperature of 60 ° C. and a humidity of 9
Insert it in the thermo-hygrostat set to 0% RH and leave it for 20 hours to perform wet crosslinking, then 70 ℃ × 40mmHg
After drying for 2 hours in a vacuum dryer set to, the wet-cured fiber was extremely fragile and was broken by a slight bending force, and could not be put into practical use as a transparent fiber.

Comparative Example 4 90 parts by weight of a rod-shaped resin before spinning (a homopolymer of methyl methacrylate) prepared in Comparative Example 1 and a rod-shaped resin before spinning (γ-methacryloxypropyl) prepared in Comparative Example 3 above. 10 parts by weight of a homopolymer of trimethoxysilane) was dissolved in 500 parts by weight of tetrahydrofuran to obtain a mixed solution of both polymers. Next, this mixed solution was transferred to a Teflon-coated wide container, placed in a vacuum dryer equipped with a trap, and tetrahydrofuran was evaporated while slowly depressurizing at a temperature of 60 ° C. to obtain a solid mixture of both polymers. .

The solid mixture was crushed using a stainless mortar, and the crushed product was supplied to a twin-screw kneading extruder (Kurimoto Iron Works “S1KRC Reactor”) set at 200 ° C. for melting and degassing. , Diameter 3 from the outlet
A mm melt was drawn while being drawn to obtain a comparative fiber j having a diameter of 1 mm.

This comparative fiber j was inserted into a thermo-hygrostat set to a temperature of 60 ° C. and a humidity of 90% RH, left standing for 20 hours for wet crosslinking, and then 70 ° C. × 40 mm.
Transparent fiber J was obtained by drying for 2 hours in a vacuum dryer set to Hg. In the above, the physical properties of the comparative fiber j before wet crosslinking are shown in Table 1 below, and
The physical properties and transparency of the finally obtained transparent fiber J are shown in Table 2 below.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

The present invention is configured as described above.
A thermoplastic copolymer prepared by introducing an alkoxysilyl group-containing polymerizable monomer unit into a (meth) acrylic and / or styrene polymer or copolymer by copolymerization as a wet curing component is used and melted. By adopting the method of spinning and then wet-curing, transparent fibers having both excellent optical properties and heat resistance can be produced with high productivity by a simple method.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G02B 6/00 391 G02B 6/00 391

Claims (4)

[Claims] 1. A transparent fiber, characterized in that a copolymer containing a (meth) acrylic and / or styrene monomer and an alkoxysilyl group-containing polymerizable monomer as an essential monomer unit is melt-spun and then wet-cured. Manufacturing method. 2. The method according to claim 1, wherein the wet curing is performed in an atmosphere having a temperature of 20 to 100 ° C. and a relative humidity of 40 to 100% RH. 3. The glass transition temperature of the transparent fiber is 11.
Yield point at 0 ℃ or higher and 110 ℃ is 50kgf / cm
The method according to claim 1 or 2, wherein the breaking strength is ² or more and the breaking strength is 90 kgf / cm ² or more. 4. A structure having a structure in which a copolymer having repeating units represented by the following formulas X and Y is crosslinked by a siloxane bond in the molecular chain, and has a glass transition temperature of 1
Yield point at 10 ℃ or higher and 110 ℃ is 50kgf / c
m ² or more, the transparent fiber, wherein the breaking strength of 90 kgf / cm ² or more. Embedded image