JPH0665328A - Fluorinated acrylic rubber composition - Google Patents

Abstract

PURPOSE:To obtain a fluorinated acrylic rubber compsn. which retains a high transparency even without using an expensive fluorine compd. as a crosslinker by copolymerizing a fluorinated acrylate, an allyl (meth)acrylate, and a specific monomer as a compatibilizer for a crosslinker. CONSTITUTION:This resin compsn. comprises a (meth)acrylate copolymer (A) obtd. by copolymerizing a fluorinated acrylate (a) of formula I (wherein X is H or F; (n) is 0, 1, or 2; and (m) is 1-8), an allyl (meth)acrylate (b), and a (meth)acrylate (c) of formula II (wherein R is H or CH3; R' is H or lower alkyl; and (p) is 1-4), a crosslinker component (B) comprising the monomer (c) and a di(meth)acrylate (d) of formula III (wherein R is H or CH3; and (q) is 1-10), and an org. peroxide initiator or a photopolymn. initiator (C). Monomer (a) forms the main part of the copolymer A; monomer (b) provides crosslinking sites; and monomer (c) acts as a compatibilizer for component B, thus enabling the crosslinking without using an expensive fluorine compd. as the crosslinker.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fluorine-containing acrylic rubber composition. More specifically, it relates to a fluorine-containing acrylic rubber composition used as a clad material material for optical fibers.

[0002]

2. Description of the Related Art Conventionally, it has been known that a polymer of fluorine-containing (meth) acrylate is effectively used as a clad material material for an optical fiber made of (meth) acrylic resin.
Little is known about a clad material for an optical fiber having rubber-like elasticity.

That is, regarding this kind of application material, a fluorine-containing acrylate-dicyclopentenyl group-containing (meth) acrylate copolymer is only slightly proposed by the present applicant (JP-A-2-48603). However, in order to further improve the performance (high optical transmission) of the optical fiber, it was recognized that it is necessary to further increase the transparency of the clad material.

In the above-mentioned copolymer, a photopolymerizable monomer or oligomer is added as a co-crosslinking agent for the purpose of improving the physical properties, but when these are not fluorine-containing compounds, the molded product becomes cloudy, There was a problem of decreasing transparency. This is considered to be due to the poor compatibility between the copolymer and the fluorine-free compound. On the other hand, those in which the photopolymerizable monomer or oligomer is a fluorine-containing compound are good in terms of transparency of the molded product, but these fluorine-containing compounds are very expensive and are not practical in that respect. There's a problem.

[0005]

The object of the present invention is to provide a fluorine-containing compound which can maintain high transparency even if a fluorine-free compound co-crosslinking agent is used as an essential polymerizable monomer or oligomer for the purpose of improving physical properties. An object is to provide an acrylic rubber composition.

[0006]

The object of the present invention is as follows.
(I) (a) General formula CH ₂ = CHCOO (CH ₂ ) n (CF ₂ ) mX (where X is a hydrogen atom or a fluorine atom, and n is 0,1
Or 2 and m is an integer of 1 to 8), (b) allyl (meth) acrylate and (c) the general formula CH ₂ = CRCOO (CH ₂ CH ₂ O) pR ′ ( Here, R is a hydrogen atom or a methyl group, R'is a hydrogen atom or a lower alkyl group, and p is an integer of 1 to 4) (meth) acrylate copolymer, (II )
The above (c) (meth) acrylate and (d) general formula _{CH 2 = CRCOO (CH 2 CH} 2 O) qCOCR = CH 2 ( wherein, R represents a hydrogen atom or a methyl group, q is 1 to 10
Which is an integer of 1) and a (III) organic peroxide-based reaction initiator or photopolymerization initiator.

The main part of the component (I) copolymer is the component (a)
Of fluorinated acrylate. Such inclusion
Examples of fluorine acrylate include CH₂= CHCOO (CH₂)₂C₈F₁₇  CH₂= CHCOO (CH₂)₂C₆F₁₃  CH₂= CHCOOCH₂(CF₂)_FourH CH₂= CHCOOCH₂(CF₂)₂H CH₂= CHCOOCH₂CF₃ And so on. These fluorinated acrylates are
About 50 to 90 mol% in the copolymer, preferably about 60 to 86 mol%
Used in proportion to occupy. Below this, the optical fiber
The effect of lowering the index of refraction as the cladding of iva is small, while
Copolymerization at a rate higher than this will result in copolymers added later.
Fluorine-free monomer or oligomer as a cross-linking agent
The compatibility is not satisfied.

The component (b), allyl (meth) acrylate, is
As a monomer for introducing a crosslinking point into the copolymer, about 0.5
.About.5 mol%, preferably about 1 to 5 mol%.

The (meth) acrylate of the component (c) is
The side chain has an ethylene glycol chain or an ethylene glycol chain whose end is a lower alkyl ether,
It acts as a compatibilizer with a co-crosslinking agent added later, and is copolymerized in the copolymer in an amount of about 5 to 49.5 mol%, preferably about 8 to 30 mol%.

The copolymerization reaction is carried out by a solution polymerization method, an emulsion polymerization method or the like, but the solution polymerization method is optimal in order to avoid the formation of gel components as much as possible. At that time, a chain transfer agent typified by an organic mercapto compound is preferably used by adding at a ratio of about 0.2 mol% or less with respect to the monomer mixture, which effectively prevents gelation of the copolymer. . It is desirable that the copolymerization reaction be stopped within a conversion rate of about 50% in order to maintain the uniformity of the composition. After completion of the polymerization reaction, the copolymer is purified by a method such as reprecipitation to remove unreacted monomers and other impurities,
A copolymer having a number average molecular weight (polystyrene-equivalent molecular weight by gel permeation chromatography) of about 10,000 or more, preferably about 50,000 or more is obtained.

In the copolymer, at least one of the (meth) acrylate (c) and the di (meth) acrylate (d) as a co-crosslinking agent is used in an amount of about 2 per 100 parts by weight of the copolymer.
.About.20 parts by weight, preferably about 4 to 20 parts by weight.

The composition comprising each of the above components is crosslinked by heating, irradiation with active energy rays, or the like. At that time, an organic peroxide-based reaction initiator or photopolymerization initiator which is generally used is a copolymer. It is used by adding in an amount of about 0.05 to 3 parts by weight, preferably about 0.05 to 1 part by weight, per 100 parts by weight of the coalescence.

[0013]

INDUSTRIAL APPLICABILITY According to the present invention, copolymerization is carried out by copolymerizing a monomer that forms an ethylene glycol chain in a side chain, which acts as a compatibilizing agent for a co-crosslinking agent in a fluorine-containing acrylic copolymer. Even if an expensive fluorine-containing compound is not used as the agent, a crosslinked product that does not cause a decrease in light transmittance due to microphase separation or the like can be obtained. Therefore, it is possible to inexpensively obtain the clad material of the optical fiber having high transparency.

[0014]

EXAMPLES The present invention will now be described with reference to examples.

Example 1 CH ₂ = CHCOOCH ₂ (CF ₂ ) ₄ H [OFPA] 949.5 (g) CH ₂ = C (CH ₃ ) COOCH ₂ CH = CH ₂ [ALMA] 15.0 CH ₂ = C (CH ₃ ) COO (CH ₂ CH ₂ O) ₂ CH ₃ [2-EGMMA] 112.8 Azobisisobutyronitrile 0.322 2-Mercaptoethanol 0.936 Methylethylketone 432 The above mixture was placed in a separable flask with a volume of 5 L and heated to 50 ° C. for 2 hours. It was heated for an hour and copolymerized to a conversion of 20%.
After the reaction was stopped, this solution polymer was reprecipitated with n-hexane and purified to obtain OFPA-ALMA-2-EGMMA (molar ratio 83: 2: 15) terpolymer.
210 g of (number average molecular weight 62000) was obtained.

100 parts by weight of terpolymer CH ₂ ═CHCOO (CH ₂ CH ₂ O) ₄ COCH═CH ₂ [4-EGDA] 10 2-hydroxy-2-methyl-1-phenylpropan-1-one [ HMPP] 0.5 (Merck Darocur 1173 product) The above composition was cast on a glass plate, and 500 W xenon-
Using a mercury lamp (UXM-501MD lamp manufactured by Ushio Inc.), light irradiation was performed from a distance of 20 cm for 5 seconds in a nitrogen gas atmosphere to obtain a film-shaped molded product of 80 × 80 × 0.5 mm having the following properties. Light transmittance (by UV-VIS spectrophotometer) 93.5% Tensile strength 54kgf / cm ² Growth 220%

Examples 2 to 3 and Comparative Examples 1 to 2 According to Example 1, copolymerization reaction and heat crosslinking or photocrosslinking were carried out. (Margins) Table Example Comparative Example 2 3 1 2 [Copolymerization composition: molar ratio] OFPA 72 98 TFPA 87 96 ALA 3 ALMA 1 2 4 2-EGA 25 2-EGMMA 12 [co-crosslinking agent: parts by weight] 3 -EGDA 5 5 4-EGDMA 5 2-EGDMA 10 4-EGDA 10 [Cross-linking initiator: parts by weight] PH3M 0.5 HMPP 0.1 0.5 0.2 [Measurement result] Light transmittance (%) 93.8 93.3 86.5 88.8 Tensile strength (kgf / cm ² ) 52 58 55 48 Elongation (%) 269 240 202 225 Note) TFPA: CH ₂ ＝ COOCH ₂ (CF ₂ ) ₂ H ALA ： CH ₂ ＝ CHCOOCH ₂ CH ＝ CH ₂ 2-EGA: CH ₂ = CHCOO (CH ₂ CH ₂ O) ₂ H 3-EGA: CH ₂ = CHCOO (CH ₂ CH ₂ O) ₃ H 4-EGDMA: CH ₂ = C (CH ₃ ) COO (CH ₂ CH ₂ O) ₄ COC (CH ₃ ) ＝ CH ₂ 2-EGDMA: CH ₂ ＝ C (CH ₃ ) COO (CH ₂ CH ₂ O) ₂ COC (CH ₃ ) ＝ CH ₂ PH3M: Organic peroxide (Nippon Oil & Fat Products Perhexa 3M)

Claims (3)

[Claims] 1. (I) (a) The general formula CH ₂ ═CHCOO (CH ₂ ) n (CF ₂ ) mX (where X is a hydrogen atom or a fluorine atom, and n is 0,1).
Or 2 and m is an integer of 1 to 8), (b) allyl (meth) acrylate and (c) the general formula CH ₂ = CRCOO (CH ₂ CH ₂ O) pR ′ ( Here, R is a hydrogen atom or a methyl group, R'is a hydrogen atom or a lower alkyl group, p is an integer of 1 to 4) (meth) acrylate copolymer represented by, (II ) (c) above of (meth) acrylate and (d) general formula _{CH 2 = CRCOO (CH 2 CH} 2 O) qCOCR = CH 2 ( wherein, R represents a hydrogen atom or a methyl group, q is 1 to 10
The fluorine-containing acrylic rubber composition comprises at least one di (meth) acrylate represented by the formula (3) and (III) an organic peroxide-based reaction initiator or a photopolymerization initiator. 2. (a) The general formula CH ₂ ═CHCOO (CH ₂ ) n (CF ₂ ) mX (where X is a hydrogen atom or a fluorine atom, and n is 0,1).
Or 2 and m is an integer of 1 to 8) fluorinated acrylate represented by 50 to 90 mol%, (b) allyl (meth) acrylate 0.5 to 5 mol% and (c) the general formula CH ₂ = CRCOO _{(CH 2 CH 2 O) pR'} ( wherein, R represents a hydrogen atom or a methyl group, R'is a hydrogen atom or a lower alkyl group, p is a is an integer of 1-4) is represented by ( (Meth) acrylate is a copolymer of 5 to 49.5 mol%, the number average molecular weight (polystyrene conversion molecular weight by gel permeation chromatography) is 100
Fluorine-containing acrylic rubber of 00 or more. 3. (a) The general formula CH ₂ ═CHCOO (CH ₂ ) n (CF ₂ ) mX (where X is a hydrogen atom or a fluorine atom, and n is 0,1).
Or 2 and m is an integer of 1 to 8), (b) allyl (meth) acrylate and (c) the general formula CH ₂ = CRCOO (CH ₂ CH ₂ O) pR ′ ( Here, R is a hydrogen atom or a methyl group, R'is a hydrogen atom or a lower alkyl group, p is an integer of 1 to 4) represented by (meth) acrylate And a method for producing a fluorine-containing acrylic rubber.