JP6927283B2 - Fluorine-containing polymer, method for producing its cured product, and light emitting device - Google Patents

Description

The present invention relates to a fluorine-containing polymer, a method for producing a cured product thereof, and a light emitting device.

In recent years, white LEDs (Light Emitting Diodes) have been put into practical use by replacing incandescent lamps and fluorescent lamps as light sources for high-efficiency lighting. Ultraviolet (UV) LEDs have also been increased in output to replace mercury lamps and are beginning to be used in various industrial processes. In an LED lamp using a white LED or a UV LED, the LED element is sealed (molded) with a translucent resin such as a silicone resin in order to protect the LED element from external physical and chemical actions. However, in UV LEDs, the translucent resin is deteriorated by the ultraviolet rays and heat emitted by the LEDs. Further, also in the case of white LEDs, for example, in LED lamps such as automobile headlamps and outdoor lighting that require high output, the translucent resin that seals the LED element deteriorates. For this reason, the LED element is protected by using a glass cap or lid without using resin, and there is a problem that the structure of the LED lamp becomes complicated and the cost becomes high.

As a translucent resin having high heat resistance and light resistance for sealing high-power LEDs such as white LEDs and UV LEDs, a curable fluorine-containing polymer having _{a carboxylic acid alkyl ester group, for example, three COOCH groups has been proposed.} (See, for example, Patent Document 1). This curable fluorine-containing polymer is cured by irradiation with active energy rays to obtain a cured product having excellent stability and ultraviolet light transmission.

International Publication No. 2015/098773

However, according to the study of the present inventor, since the fluorine-containing polymer described in Patent Document 1 requires ultraviolet (UV) irradiation for curing, a shadow portion in the LED element structure that is not irradiated with UV. If there is, there is a problem that insufficient curing occurs in the relevant part.

An object of the present invention is to provide a fluorine-containing polymer capable of thermosetting, having good melt moldability, and providing a cured product having high heat resistance and UV resistance and high transparency, and a method for producing the cured product.

The present invention provides a fluorine-containing polymer having the following configurations [1] to [11], a method for producing a cured product of the fluorine-containing polymer, a light emitting device, and a light emitting device.
[1] A fluorine-containing polymer containing a unit represented by the following formula (1) and a unit represented by the following formula (2).

（式（１）中、Ｒ^ｆ１は、フルオロアルキレン基、または炭素−炭素原子間にエーテル性酸素原子を有する炭素数２以上のフルオロアルキレン基であり、Ｒ^１、Ｒ^２は、それぞれ独立に、水素原子またはアルキル基である。）

(In the formula (1), R ^f1 is a fluoroalkylene group or a fluoroalkylene group having an ether oxygen atom between carbon atoms and having two or more carbon atoms, and R ¹ and R ² are independent of each other. It is a hydrogen atom or an alkyl group.)

（式（２）中、Ｘ^１、Ｘ^２、Ｘ^３はそれぞれ独立にフッ素原子または水素原子であり、２つのＱ^２はそれぞれ独立に単結合またはエーテル性酸素原子であり、Ｒ^ｆ２は炭素数１〜６のフルオロアルキレン基、または炭素−炭素原子間にエーテル性酸素原子を有する炭素数２〜２５のフルオロアルキレン基である。）
［２］式（１）で表される単位の少なくとも一部が、−［ＣＦ_２−ＣＦ（Ｏ（ＣＦ_２）_３ＣＯＮＨＮＨ_２）］−である、［１］に記載の含フッ素重合体。
［３］さらに、フルオロエチレン由来の単位を含む、［１］または［２］に記載の含フッ素重合体。

(In the formula ^{(2), X 1, X} 2, X 3 are each independently a fluorine atom or a hydrogen atom, two ^{Q 2} are each a single bond or an ether oxygen atom ^{independently, R f2} is the number of carbon atoms It is a fluoroalkylene group of 1 to 6 or a fluoroalkylene group having 2 to 25 carbon atoms having an ethereal oxygen atom between carbon-carbon atoms.)
[2] The fluorine-containing polymer according to [1], wherein at least a part of the unit represented by the formula (1) is − [CF _2- CF (O (CF ₂ ) ₃ CONNHN _{2)] −.}
[3] The fluorine-containing polymer according to [1] or [2], which further contains a unit derived from fluoroethylene.

[4] The fluorine-containing polymer according to any one of [1] to [3], further comprising a unit represented by the following formula (3) (excluding units derived from fluoroethylene).
-[CX ⁴ X ^5- CY ¹ Y ² ]-... (3)
(In the formula (3), ^{X 4} and ^{X 5} are each independently a hydrogen atom, a fluorine atom or a chlorine atom,
Y ¹ is a hydrogen atom, a fluorine atom or a chlorine atom,
Y ² is a hydrogen atom, a fluoroalkyl group, a fluoroalkyl group having 2 or more carbon atoms having an ether oxygen atom between carbon and carbon atoms, a fluoroalkoxy group, or a carbon having an ether oxygen atom between carbon and carbon atoms. It is a fluoroalkoxy group of several 2 or more. )

[5] The ratio of the units represented by the formula (1) is 0.1 to 20 mol% with respect to the total of the units contained in the fluorine-containing polymer, and the ratio of the units represented by the formula (2) is The fluorine-containing polymer according to any one of [1] to [4], which is 0.05 to 3 mol%.
[6] The ratio of the units represented by the formula (1) is 0.1 to 5 mol% with respect to the total of the units contained in the fluorine-containing polymer, and the ratio of the units represented by the formula (2) is The fluorine-containing polymer according to any one of [1] to [4], which is 0.05 to 3 mol%.
[7] The fluorine-containing polymer according to any one of [1] to [6], which has a mass average molecular weight of 3,000 to 100,000.
[8] The fluorine-containing polymer according to any one of [1] to [6], which has a mass average molecular weight of 5,000 to 100,000.

[9] A method for producing a cured product of a fluorinated polymer, which comprises heating the fluorinated polymer according to any one of [1] to [8] at 150 to 300 ° C.
[10] A light emitting device including a light emitting device and a cured product of the fluorine-containing polymer according to any one of [1] to [8].
[11] The light emitting device according to [10], wherein the light emitting element is a white LED or an ultraviolet LED.

According to the present invention, it is possible to provide a method for producing a fluorine-containing polymer and a cured product of a fluorine-containing polymer, which can be thermally cured, has good melt moldability, and provides a cured product having high heat resistance and UV resistance and high transparency. ..

Hereinafter, embodiments of the present invention will be described. The present invention is not construed as being limited to the following description.

[Meaning of terms in the present specification]
The compound represented by the formula (a) may be referred to as a compound (a). Compounds represented by other formulas are also described in the same manner. The unit represented by the formula (b) may be referred to as a unit (b). The units expressed by other formulas are also described in the same manner.

The “translucent sealing” means a sealing having both a function of transmitting light and a sealing function.

The "unit" in a polymer means a portion derived from the monomer formed by polymerizing the monomer. A unit derived from a monomer may be simply referred to as a monomer unit.

"Fluoroethylene" means a compound _{in which 0 to 3 fluorine atoms of tetrafluoroethylene (CF 2} = CF ₂ ) are replaced with hydrogen atoms or halogen atoms other than fluorine (for example, chlorine, bromine, iodine). do.

The group having a carbon atomic chain such as an alkyl group, a fluoroalkyl group, a fluoroalkylene group, a fluoroalkoxy group, and a fluoroalkoxy group may be linear or branched.

"Fluoroalkyl group" refers to a group in which one or more hydrogen atoms of an alkyl group are substituted with fluorine atoms. The ratio of fluorine atoms in the fluoroalkyl group is expressed as (the number of fluorine atoms in the fluoroalkyl group) / (the number of hydrogen atoms in the alkyl group having the same number of carbon atoms as the fluoroalkyl group) × 100 (%). It is preferably 50% or more, and 100%, that is, a perfluoroalkyl group is particularly preferable. The same applies to the fluoroalkylene group and the fluoroalkoxy group, and the perfluoroalkylene group and the perfluoroalkoxy group are preferable.
"Curing" means curing by cross-linking unless otherwise stated.

[Fluorine-containing polymer]
The fluorine-containing polymer of the present embodiment includes a unit represented by the following formula (1) and a unit represented by the following formula (2).

(In formula (1), R ¹ and R ² are independently hydrogen atoms or alkyl groups, respectively.
R ^f1 is a fluoroalkylene group or a fluoroalkylene group having 2 or more carbon atoms having an ethereal oxygen atom between carbon-carbon atoms. )

(In the formula ^{(2), X 1, X} 2, X 3 are each independently a fluorine atom or a hydrogen atom, two ^{Q 2} are each a single bond or an ether oxygen atom ^{independently, R f2} is the number of carbon atoms It is a fluoroalkylene group of 1 to 6 or a fluoroalkylene group having 2 to 25 carbon atoms having an ethereal oxygen atom between carbon-carbon atoms.)

The present inventors have newly found that in a fluorine-containing polymer having a unit (1) and a unit (2), -CONNHN ₂ reacts with each other and crosslinks between molecules by heating. Since the fluorine-containing polymer of the present embodiment is _{crosslinked only with −CONNHN 2} , the fluorine-containing polymer can be cured with a small amount of cross-linking groups. Therefore, the cured product is excellent in transparency and heat resistance, and is excellent in light resistance, particularly UV resistance. Further, since the fluorine-containing polymer of the present embodiment contains the unit (1) and the unit (2), it can be cured with a small amount of cross-linking groups, so that the melt fluidity is impaired during LED molding. Foaming can be suppressed without any need, and the melt moldability is also excellent.

The present inventors have previously investigated a fluorine-containing polymer having _{-CONNHN 2} and -COOCH _3. In the fluorine-containing polymer, it is considered that the cross-linking reaction represented by the following formula (11) occurs by heating.
−CONNHN ₂ + −COOCH ₃ → −CONNHNCO− (11)

Although the cross-linking reaction mechanism of the fluorine-containing polymer of the present embodiment is not clear, it is considered as follows. _{For example, a compound having -CONNHN 2} , like the fluorine-containing polymer of the present embodiment, for example, phthalic acid dihydrazide is oxidatively coupled with an oxidizing agent in a polar solvent as shown by the following formula (12). It is known that poly (diacylhydrazine) can be obtained.

On the other hand, the fluorine-containing polymer having the fluoroacylhydrazide structure of the present embodiment in the side chain can be heated in air to obtain a cured product. Further, a cured product can be obtained by heating the fluorine-containing polymer of the present invention even in an N ₂ atmosphere. For example, by heating at 150 ° C. or higher or irradiating with active energy rays, no oxidizing agent is used. A cured product is obtained. As a cross-linking reaction mechanism of this fluorine-containing polymer, as shown by the following formula (13), it is considered that hydrazine is thermally decomposed and coupled to form diacyl hydrazine without an oxidation reaction. Further, as shown by the following formula (14), tetrazine may be formed by the dehydration cyclization reaction. In the case of obtaining a cured product from the fluorine-containing polymer of the present embodiment is preferable in that less colored cured product from the heated in air to heat in an N ₂ atmosphere.

2-CONHNH ₂ → -CONHNHCO- (13)

Hereinafter, each unit contained in the fluorine-containing polymer of the present embodiment will be described.

<Unit (1)>
The unit (1) is a unit represented by the following formula (1).

In the unit (1), R ¹ and R ² are independently hydrogen atoms or alkyl groups, and R ^f1 has a fluoroalkylene group or an ether oxygen atom between carbon-carbon atoms and has 2 or more carbon atoms. Fluoroalkylene group.

In the unit (1), when R ^f1 is a fluoroalkylene group, the number of carbon atoms thereof is preferably 1 to 6, and particularly preferably 1 to 4. When the ^{number of carbon atoms of R f1} is 3 or more, a linear structure is preferable from the viewpoint of excellent thermal stability. The fluoroalkylene group is preferably a perfluoroalkylene group from the viewpoint of excellent thermal stability. That is, as R ^f1 , a perfluoroalkylene group having 1 to 6 carbon atoms is preferable, and a perfluoroalkylene group having 1 to 4 carbon atoms is particularly preferable.

In the unit (1), when R ^f1 is a fluoroalkylene group having 2 or more carbon atoms having an ethereal oxygen atom between carbon atoms, ^{the carbon number of R f1} is preferably 2 to 10, preferably 2 to 6. Especially preferable. When the ^{number of carbon atoms of R f1} is 3 or more, a linear structure is preferable from the viewpoint of excellent thermal stability. The fluoroalkylene group is preferably a perfluoroalkylene group from the viewpoint of excellent thermal stability. That is, as R ^f1 , a perfluoroalkylene group having 2 to 10 carbon atoms having an ether oxygen atom between carbon atoms is preferable, and perfluoro having 2 to 6 carbon atoms having an ether oxygen atom between carbon atoms is preferable. An alkylene group is particularly preferred.

R ¹ and R ² are preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and particularly preferably a hydrogen atom, from the viewpoint of excellent heat curability.

Specific examples of the unit (1) include the following units.
-[CF _2- CF (O (CF ₂ ) ₂ CONNHN ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₂ CON (CH ₃ ) NH ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₂ CONNHNHCH ₃ )]-,
-[CF _2- CF (O (CF ₂ ) ₃ CONNHN ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₃ CON (CH ₃ ) NH ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₃ CONNHNHCH ₃ )]-,
-[CF _2- CF (O (CF ₂ ) ₄ CONNHN ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₄ CON (CH ₃ ) NH ₂ )]-
-[CF _2- CF (O (CF ₂ ) ₄ CONNHNHCH ₃ )]-,
-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ CONNHN ₂ )]-,
-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ CON (CH ₃ ) NH ₂ )]-,
-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ CONNHNHCH ₃ )]-,
-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₃ CONNHN ₂ )]-,
-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₃ CON (CH ₃ ) NH ₂ )]-,
-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₃ CONNHNHCH ₃ )]-
-[CF _2- CF (O (CF ₂ ) ₃ O (CF ₂ ) ₂ CONNHN ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₃ O (CF ₂ ) ₂ CON (CH ₃ ) NH ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₃ O (CF ₂ ) ₂ CONNHNHCH ₃ )]-,
-[CF _2- CF (O (CF ₂ ) ₂ O (CF ₂ ) ₂ CONNHN ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₂ O (CF ₂ ) ₂ CON (CH ₃ ) NH ₂ )]-,
-[CF _2- CF (O (CF ₂ ) ₂ O (CF ₂ ) ₂ CONNHNHCH ₃ )]-.
From the viewpoint of easy availability, the unit (1) is _{particularly preferably − [CF 2-} CF (O (CF ₂ ) ₃ CONNHN ₂ )] −.

The fluorine-containing polymer may contain one type of unit (1) alone, or may contain two or more types of unit (1).

<Unit (2)>
The unit (2) is a unit represented by the following formula (2).

In the unit ^{(2), X 1, X} 2, X 3 are each independently a fluorine atom or a hydrogen atom, two ^{Q 2} is a single bond or an ether oxygen atom ^{independently, R f2} is 1 carbon atoms It is a fluoroalkylene group having ~ 6 or a fluoroalkylene group having 2 to 25 carbon atoms having an ethereal oxygen atom between carbon-carbon atoms. Two of X ¹ in the unit (2) may be the same or different. The same applies to the ^{two X 2} and the two X ^3. The two Q ² 'in the unit (2) may be the same or different.

In the unit (2), X ¹ , X ² , and X ³ are all fluorine atoms, or all are hydrogen atoms. If when X ^{1, X} 2, ^{X 3} is a fluorine atom, the two ^{Q 2} 'are both etheric oxygen atom is ^preferred, X ^1, X 2, ^{X 3} both are hydrogen atoms Is preferably a single bond in both of the ^{two Q2s.}

In the unit (2), when R ^f2 is a fluoroalkylene group having 1 to 6 carbon atoms, the carbon number is preferably 2 or more. When the ^{number of carbon atoms of R f2} is 3 or more, a linear structure is preferable from the viewpoint of excellent thermal stability. The fluoroalkylene group is preferably a perfluoroalkylene group from the viewpoint of excellent thermal stability. That is, as R ^f2 , a perfluoroalkylene group having 1 to 6 carbon atoms is preferable, and a perfluoroalkylene group having 2 or more carbon atoms is more preferable.

When R ^f2 is a fluoroalkylene group having 2 to 25 carbon atoms having an etheric oxygen atom between carbon atoms, the carbon number is preferably 2 to 10 and particularly preferably 2 to 6. When the ^{number of carbon atoms of R f2} is 3 or more, a linear structure is preferable from the viewpoint of excellent thermal stability. The fluoroalkylene group is preferably a perfluoroalkylene group from the viewpoint of excellent thermal stability. That is, as R ^f2 , a perfluoroalkylene group having 2 to 10 carbon atoms having an ether oxygen atom between carbon atoms is preferable, and perfluoro having 2 to 6 carbon atoms having an ether oxygen atom between carbon atoms is preferable. The alkylene group is more preferable. Perfluoroalkylene groups having 2 to 6 carbon atoms having an etheric oxygen atom between carbon atoms are − (CF ₂ O) −, − (CF ₂ CF ₂ O) −, − (CF ₂ CF (CF ₃ )). It preferably contains one or more of the perfluoropolyether units represented by O) − and − (CF ₂ CF ₂ CF _{2 O) −.}

Specific examples of the unit ^{(2), X 1, X} 2, X 3 are both fluorine atoms, any two ^{Q 2} 'is etheric oxygen ^{atom, R f2} is - _{(CF 2) 2} - ,-(CF ₂ ) ₃ -,-(CF ₂ ) ₄ -,-(CF ₂ ) ₆ -,-(CF ₂ ) ₄ OCF (CF ₃ ) CF ₂ -,-(CF ₂ ) ₂ OCF (CF ₃₎ ) CF ₂ −, − (CF ₂ CF ₂ O) ₂ −, − CF ₂ O (CF ₂ CF ₂ O) ₂ − or − _{CF 2} CF (CF ₃ ) O (CF ₂ ) ₂ OCF (CF ₃ ) CF ₂ - is a ^unit, both the X ^1, X 2, ^{X 3} is a hydrogen atom, two ^{Q 2} are both single ^{bonds, R f2} is _{- (CF 2) 2 -,} - (CF 2) Examples include units that are _4- or-(CF ₂ ) _6-.

As the unit (2), the units represented by the following formulas (21) and (22) are particularly preferable from the viewpoint of easy availability.

The unit (2) can be formed by polymerizing a fluorine-containing monomer having two polymerizable unsaturated bonds represented by the following formula (2a). Hereinafter, the fluorine-containing monomer represented by the formula (2a) is also referred to as a monomer (2a).

X ¹ X ² C = CX ^3- Q ^2- R ^f2- Q ² -CX ^{3 = CX 1} X ² (2a)
In the formula (2a), X ¹ , X ² , X ³ , Q ² , and R ^f2 are as defined in the formula (2), and the examples and the preferable ranges are the same.

Specific examples of the monomer (2a) include the following monomers.
CF ₂ = CFO (CF ₂ ) ₂ OCF = CF ₂ ,
CF ₂ = CFO (CF ₂ ) ₃ OCF = CF ₂ ,
CF ₂ = CFO (CF ₂ ) ₄ OCF = CF ₂ ,
CF ₂ = CFO (CF ₂ ) ₆ OCF = CF ₂ ,
CF ₂ = CFO (CF ₂ ) ₄ OCF (CF ₃ ) CF ₂ OCF = CF ₂ ,
CF ₂ = CFO (CF ₂ ) ₂ OCF (CF ₃ ) CF ₂ OCF = CF ₂ ,
CF ₂ = CFO (CF ₂ CF ₂ O) ₂ OCF = CF ₂ ,
CF ₂ = CFOCF ₂ O (CF ₂ CF ₂ O) ₂ OCF = CF ₂ ,
CF ₂ = CFOCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ OCF (CF ₃ ) CF ₂ OCF = CF ₂ ,
CH ₂ = CH- (CF ₂ ) ₂ -CH = CH ₂ ,
CH ₂ = CH- (CF ₂ ) ₄ -CH = CH ₂ ,
CH ₂ = CH- (CF ₂ ) ₆ -CH = CH ₂ .

<Additional unit>
The fluorine-containing polymer of the present embodiment may further have a fluoroethylene unit and a unit (3) described later.

(Fluoroethylene unit)
Specific examples of the fluoroethylene unit include tetrafluoroethylene (CF ₂ = CF ₂ ) (TFE), trifluoroethylene (CF ₂ = CHF) (TrFE), chlorotrifluoroethylene (CFCl = CF ₂ ), and vinylidene fluoride. Units derived from (CF ₂ = CH ₂ ) and the like can be mentioned. As the fluoroethylene unit, a TFE unit, a TrFE unit, and a chlorotrifluoroethylene unit are preferable from the viewpoint of excellent light resistance. As the fluoroethylene unit, a TFE unit is preferable from the viewpoint of excellent heat resistance. As a fluoroethylene unit, a highly polar -CONR ¹ NR ² H group is likely to be present at the interface, so that the cured product of the fluorine-containing polymer is excellent in adhesiveness and wettability to a substrate, and thus TFE. The unit is particularly preferred. As the fluoroethylene unit, the TrFE unit or the chlorotrifluoroethylene unit is particularly preferable because the crystallinity of the fluorine-containing polymer is not as high as that of the TFE unit, light scattering is less likely to occur, and the transparency is high. As the fluoroethylene unit, the TrFE unit is particularly preferable because it is excellent in solubility in various organic solvents. The wettability means that the surface tension of the fluorine-containing polymer is low, so that the polymer easily gets wet and spreads on the substrate.

The fluorine-containing polymer may contain one kind of fluoroethylene unit alone, or may contain two or more kinds of fluoroethylene units.

(Unit (3))
The unit (3) is a unit represented by the following formula (3) (however, excluding the fluoroethylene unit).
-[CX ⁴ X ^5- CY ¹ Y ² ]-... (3)

In formula (3), X ⁴ and X ⁵ are independently hydrogen atoms, fluorine atoms or chlorine atoms, Y ¹ is a hydrogen atom, fluorine atom or chlorine atom, and Y ² is a hydrogen atom. A fluoroalkyl group, a fluoroalkyl group having 2 or more carbon atoms having an ethereal oxygen atom between carbon-carbon atoms, a fluoroalkoxy group, and a fluoroalkoxy group having 2 or more carbon atoms having an ethereal oxygen atom between carbon-carbon atoms. be.

In Y ^2, the carbon number of the fluoroalkyl group is preferably from 1 to 15, 1 to 6 is particularly preferred. The fluoroalkyl group is preferably a perfluoroalkyl group, more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably _{-CF 3 from the viewpoint of excellent thermal stability.} In Y ^2, carbon - carbon number of the fluoroalkyl group having at least 2 carbon atoms and having a carbon atomic etheric oxygen atoms is preferably from 2 to 15, 2 to 6 is particularly preferred. From the viewpoint of excellent thermal stability, a perfluoroalkyl group having 2 or more carbon atoms having an ethereal oxygen atom between carbon atoms is preferable, and a perfluoroalkyl group having 2 to 6 carbon atoms having an ethereal oxygen atom between carbon atoms is preferable. Alkyl groups are particularly preferred.

In Y ^2, the number of carbon atoms of fluoroalkoxy group is preferably 1 to 15, 1 to 6 is particularly preferred. The fluoroalkoxy group is preferably a perfluoroalkoxy group having 1 to 6 carbon atoms from the viewpoint of excellent thermal stability, and is preferably -OCF ₃ , -OCF ₂ CF ₃ , -O (CF ₂ ) ₂ CF ₃ , -O (CF _2). ) ₃ CF ₃ is particularly preferable. In Y ^2, carbon - carbon number of fluoroalkoxy group having 2 or more carbon atoms having carbon atoms between the etheric oxygen atom is preferably 2 to 15, 2 to 6 is particularly preferred. As the fluoroalkoxy group, a perfluoroalkoxy group having 2 or more carbon atoms having an ethereal oxygen atom between carbon atoms is preferable, and carbon having an ethereal oxygen atom between carbon atoms is preferable from the viewpoint of excellent thermal stability. The number 2 to 6 of the perfluoroalkoxy group is more preferable, and −OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ CF ₃ is particularly preferable.

Specific examples of the unit (3) include the following units.
-[CH _2- CH ₂ ]-,-[CF _2- CF (CF ₃ )]-,-[CH _2- CF (CF ₃ )]-,-[CF _2- CF (OCF ₃ )]-,- [CF _2- CF (OCF ₂ CF ₃ )]-,-[CF _2- CF (O (CF ₂ ) ₂ CF ₃ )]-,-[CF _2- CF (O (CF ₂ ) ₃ CF ₃ )] -,-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ CF ₃ )]-,-[CF _2- CF (OCF ₂ CF ₂ OCF ₂ CF ₂ OCF ₂ CF ₃ )]- ..

The unit is because the glass transition temperature of the fluorine-containing polymer is low, the fluidity is excellent, and the moldability is excellent, and when the fluorine-containing polymer is cured, the mobility is high and the cross-linking reaction between molecules easily proceeds. (3) is- _{[CH 2- CH 2} ]-,-[CF _2- CF (CF ₃ )]-,-[CF _2- CF (OCF ₃ )]-,-[CF _2- CF (O (O) CF ₂ ) ₂ CF ₃ )]-,-[CF _2- CF (OCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ CF ₃ )]- _{or-[CF 2-} CF (OCF ₂ CF ₂ OCF ₂ CF) ₂ OCF ₂ CF ₃ )]-is preferable.

The fluorine-containing polymer may contain one type of unit (3) alone, or may contain two or more types of unit (3).

The unit (3) can be formed by polymerizing the compound (3a) as a monomer.
CX ⁴ X ⁵ = CY ¹ Y ² ... (3a)
In the formula (3a), X ⁴ , X ⁵ , Y ¹ and Y ² are as defined in the formula (3), and the examples and the preferable range are the same.

<Preferable Fluorine-Containing Polymer Aspect>
In addition to the unit (1), the unit (2) and the optionally contained fluoroethylene unit and the unit (3), the fluorine-containing polymer of the present embodiment may be, for example, −COOR. ^7. A unit having a group represented by -C (O) NR ⁸ OR ^{9 (R 7} is an alkyl group, and R ⁸ and R ⁹ are independently hydrogen atoms or alkyl groups) and the like may be contained. .. The fluorine-containing polymer of the present embodiment preferably comprises only the unit (1), the unit (2), and the fluoroethylene unit and the unit (3) optionally contained. From the viewpoint of improving the curability, the number of units (1) contained in the fluorine-containing polymer is preferably 3 or more per molecule of the fluorine-containing polymer.

The ratio of the unit (1) to all the units of the fluorine-containing polymer of the present embodiment is preferably 0.1 mol% or more. The ratio of the unit (1) is preferably 20 mol% or less, more preferably 10 mol% or less. The ratio of the unit (1) to all the units of the fluorine-containing polymer is adjusted so that the number of units per molecule of the fluorine-containing polymer is the above-mentioned preferable number (3 or more) according to the molecular weight of the fluorine-containing polymer. can do. For example, the ratio of the unit (1) is increased when the molecular weight of the fluorine-containing polymer is small, and decreased when the molecular weight is large. Specifically, the ratio of the unit (1) can be 1 to 10 mol% in all the units of the fluorine-containing polymer when the molecular weight of the fluorine-containing polymer is about 3,000 to less than 10,000. Further, when the molecular weight of the fluorine-containing polymer is relatively large and is about 10,000 to 10,000, the ratio of the unit (1) is preferably 0.1 to 5 mol%, more preferably 0.5 to 2 mol%, and 1 ~ 1.5 mol% is particularly preferable.

When the ratio of the unit (1) is equal to or higher than the lower limit of the above range, _{heat curing is likely to occur even if the fluorine-containing polymer does not contain -COOCH 3,} and a cured product insoluble in a solvent tends to be obtained. When the ratio of the unit (1) is not more than the upper limit of the above range, coloring and foaming when the fluorine-containing polymer is thermally cured are suppressed, and a transparent cured product can be obtained.

The ratio of the unit (2) to all the units of the fluorine-containing polymer of the present embodiment is preferably 0.05 to 3 mol%, more preferably 0.1 to 1 mol%. Since the fluorine-containing polymer contains the unit (2), the content ratio of the unit (1) can be reduced. Therefore, since coloring and foaming during thermosetting can be suppressed, the fluorine-containing polymer of the present embodiment is particularly suitable as an LED encapsulant.

When the fluorine-containing polymer of the present embodiment has fluoroethylene units, the ratio of the fluoroethylene units to all the units is preferably 50 to 90 mol%, more preferably 60 to 80 mol%. In particular, when the fluoroethylene unit is a TFE unit, the ratio is preferably 50 to 70 mol%. When it is at least the lower limit value, in addition to the light resistance, various properties based on the fluoroethylene unit (for example, when the fluoroethylene unit is the TFE unit, the heat resistance, the adhesiveness to the substrate, the wettability, etc. can be easily improved. If it is not more than the upper limit, light scattering due to crystallinity is suppressed, and when the fluoropolymer is used for sealing the UV-LED, the UV light is highly transmissive and the output of the UV-LED can be secured.

The contents of the unit (1), the unit (3) and the fluoroethylene unit in the fluorine-containing polymer ^{can be calculated by 19} F-NMR and ^{1 1} H-NMR measurements. Since it is difficult to measure the content of the unit (2), the structure CF ₂ = CFO-CF ₂ -that is involved in the polymerization is common between the unit (1) and the unit (2), and thus the polymerization reactivity thereof. Is considered to be about the same, and the content of the unit (2) is included from the charging ratio of the monomer (monomer (1a) described later) and the monomer (2a) forming the unit (1). Estimate using the content of unit (1) in the fluoropolymer.

(Molecular weight)
The mass average molecular weight of the fluorine-containing polymer of the present embodiment is preferably 3,000 to 100,000, more preferably 5,000 to 100,000. The mass average molecular weight is more preferably 10,000 to 50,000, and particularly preferably 10,000 to 30,000.

When the fluorine-containing polymer is molded by casting or the like, the mass average molecular weight of the fluorine-containing polymer is preferably 3,000 to 50,000, more preferably 5,000 to 50,000, and 10,000 to 30. 000 is particularly preferred. If the mass average molecular weight of the fluorinated polymer is at least the lower limit of this range, the cured product tends to have excellent mechanical strength and heat resistance, and if it is at least the upper limit of this range, the flow of the fluorinated polymer during molding. Sex tends to be ensured. In particular, fluidity is important when sealing an SMD type LED (LED module with a cup-shaped reflector). If the mass average molecular weight is too large, the melting temperature at the time of molding the SMD type LED becomes high, and the curing reaction rate becomes high, so that the melting fluidity decreases over time and defoaming becomes difficult. When the mass average molecular weight of the fluorine-containing polymer is in this range, the fluorine-containing polymer is suitable for encapsulating SMD type LEDs.

When the fluorine-containing polymer is used as a molded product such as a sheet, the mass average molecular weight of the fluorine-containing polymer is preferably 10,000 to 100,000, particularly preferably 20,000 to 50,000. For example, when sealing a COB type LED (an LED that does not have a reflector and collectively seals a plurality of elements with a sealing resin), a sheet-shaped sealing resin may be used for heat sealing. be. In this case, the LED element is sealed by superimposing a sheet-shaped fluorine-containing polymer on a substrate on which the LED element is mounted, heating and flowing the LED element at 100 to 150 ° C., covering the LED element with the fluorine-containing polymer, and cross-linking the LED element. can. At this time, in order to seal without leaving gaps or bubbles, it is preferable to cover the sheet of the fluorine-containing polymer while applying pressure. When the mass average molecular weight of the fluorine-containing polymer is in this range, the fluorine-containing polymer is suitable for encapsulating a COB type LED as described above.

The mass average molecular weight can be determined by gel permeation chromatography (GPC) as a PMMA (polymethylmethacrylate) converted molecular weight.

[Method for producing fluorine-containing polymer]
The fluorine-containing polymer is also referred to as a fluorine-containing polymer containing a unit and a unit (2) represented by the following formula (1a) and a hydrazine compound represented by the following formula (5) (hereinafter, also referred to as “hydrazine compound”. ) Is obtained by the method of reacting with.

ＨＲ^１Ｎ−ＮＲ^２Ｈ （５）

HR ¹ N-NR ² H (5)

In formula (1a), R ³ is an alkyl group, R ^f1 is as defined in formula (1), and the same is true for both examples and preferred ranges. In the formula (5), R ¹ and R ² are as defined in the formula (1), and the examples and the preferable range are the same.

The completion of the reaction of converting the fluorine-containing polymer having the unit (1a) to the unit (1) by the reaction with the hydrazine compound can be confirmed by the disappearance of infrared (IR) absorption of ^{three -COOR groups.}

(Fluorine-containing polymer containing the unit (1a))
The fluorine-containing polymer containing the unit (1a) of the present embodiment can be obtained by polymerizing the monomer forming the unit by a known method (for example, the method described in International Publication No. 2015/098773). ..

(Hydrazine compound)
Examples of the hydrazine compound include hydrazine, hydrazine monohydrate, methylhydrazine, and 1,2-dimethylhydrazine. As the hydrazine compound, hydrazine monohydrate is preferable from the viewpoint of safety and heat curability of the obtained fluorine-containing polymer. The form of the hydrazine compound subjected to the reaction may be an aqueous solution or a salt. As the hydrazine compound, a commercially available product can be used.

(Reaction condition)
The amount of the hydrazine compound used is preferably 1 to 20 mol, more preferably 1.2 to 10 mol, with respect to 1 mol of the group represented by ^{−COOR 3} of the fluorine-containing polymer containing the unit (1a). .5-5 mol is particularly preferred.

The reaction of the fluorinated polymer having the unit (1a) with the hydrazine compound can be carried out in the presence of a solvent. As the solvent, those that dissolve the raw material components (fluorine-containing polymer containing the unit (1a) and the unit (2), the hydrazine compound) are preferable. A fluorinated solvent that dissolves the fluorinated polymer containing at least the unit (1a) and the unit (2) is more preferable. Further, alcohol may be added to the fluorine-containing solvent to disperse the hydrazine compound.

The fluorine-containing solvent contains fluorine and carbon, and may contain chlorine, oxygen and hydrogen. Examples of the fluorinated solvent include fluorinated alkanes, fluorinated aromatic compounds, fluoroalkyl ethers, fluorinated alkylamines, fluoroalcohols and the like.

The fluorinated alkane preferably has 4 to 8 carbon atoms. Commercially available products of fluorinated alkanes include, for example, CF ₃ CH ₂ CF ₂ H (HFC-245fa), CF ₃ CH ₂ CF ₂ CH ₃ (HFC-365 mfc), perfluorohexane, 1H-perfluorohexane, perfluorooctane, C ₆ F ₁₃ H (Asahi Glass Co., Ltd., Asahi Clean (registered trademark) AC-2000), C ₆ F ₁₃ C ₂ H ₅ (Asahi Glass Co., Ltd., Asahi Clean (registered trademark) AC-6000), C ₂ F ₅ CHFCHFCF ₃ ( Bertrel (registered trademark) XF) manufactured by Chemers, etc. can be mentioned.

Examples of the fluorinated aromatic compound include hexafluorobenzene, trifluoromethylbenzene, perfluorotoluene, and bis (trifluoromethyl) benzene.

The fluoroalkyl ether preferably has 4 to 12 carbon atoms. Commercially available fluoroalkyl ethers include, for example, CF ₃ CH ₂ OCF ₂ CF ₂ H (Asahi Glass Co., Ltd., Asahi _{Clean® AE-3000), C 4} F ₉ OCH ₃ (3M Co., Ltd., Novec (registered trademark)). ) 7100), C ₄ F ₉ OC ₂ H ₅ (3M, Novec® 7200), C ₂ F ₅ CF (OCH ₃ ) C ₃ F ₇ (3M, Novec® 7300) And so on.

Examples of the fluorinated alkylamine include perfluorotripropylamine and perfluorotributylamine.

Examples of the fluoroalcohol include 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, hexafluoroisopropanol and the like.

Other examples of the fluorine-containing solvent include dichloropentafluoropropane (HCFC-225) and perfluoro (2-butyl tetrahydrofuran). A commercially available product of dichloropentafluoropropane is AK-225cc (manufactured by Asahi Glass Co., Ltd.).

The reaction is preferably carried out, for example, by dissolving the fluorine-containing polymer containing the unit (1a) and the unit (2) in the above-mentioned fluorine-containing solvent, and adding the hydrazine compound at 0 to 30 ° C. This is further heated to 30 to 100 ° C. and reacted for 1 minute to 10 hours to obtain the desired fluorine-containing polymer.

[Curable composition, coating composition]
The cured product of the fluorinated polymer of the present embodiment can be produced by using only the fluorinated polymer. Further, it can be produced from a curable composition containing the fluorine-containing polymer (however, no solvent is contained) or a coating composition containing the curable composition and a solvent.

Examples of the components other than the fluorine-containing polymer in the curable composition include inorganic particles, a silane coupling agent, a fluoropolyether compound, and the like, and these components do not significantly affect the transparency of the cured product. Can be added. Here, examples of the silane coupling agent and the fluoropolyether compound include those described in International Publication No. 2015/098773.

As the inorganic particles, metal oxides such as silica, titania, zirconia, and alumina and various phosphor particles are preferable. The diameter of the inorganic particles is preferably 1 nm to 10 μm, and particularly preferably 1 nm to 1 μm from the viewpoint of suppressing light scattering and ensuring the transparency of the composition. The content of the inorganic particles is preferably 20 to 200 parts by mass, particularly preferably 50 to 100 parts by mass with respect to 100 parts by mass of the fluorine-containing polymer, from the viewpoint of increasing the refractive index of the cured product. When the content of the inorganic particles is at least the lower limit of the above range, the refractive index of the cured product is higher, and when it is at least the upper limit of the above range, the moldability is excellent.

Examples of the solvent in the coating composition include the fluorine-containing solvent. The coating composition may contain an alcohol as long as the fluorine-containing polymer does not precipitate.

The solid content in the coating composition is preferably 1 to 99% by mass. The content of the fluorine-containing polymer in the coating composition is preferably 1 to 99% by mass.

[Method for producing a cured product formed from a fluorine-containing polymer]
The cured product formed from the fluorinated polymer having a hydrazide group in the present embodiment is produced by a method of heating the fluorinated polymer or irradiating the fluorinated polymer with active energy rays. Heating and irradiation with active energy rays may be used in combination. In particular, it is preferable to heat and cure the fluorine-containing polymer. When the fluorine-containing polymer is heated and cured, the heating temperature is preferably 150 to 300 ° C, more preferably 200 to 250 ° C. The heating time depends on the temperature, but is preferably 1 minute to 10 hours, more preferably 1 to 5 hours, and even more preferably 2 to 4 hours.

[Manufacturing method of molded product]
The molded product can be produced by using a curable composition containing a fluorine-containing polymer, or a coating composition containing a curable composition and a solvent. As a method for producing a molded product, a method in which a curable composition is made to flow by heating and poured into a mold to form a predetermined shape, or a curable composition is cast on the surface of a mold to form a sheet-shaped or film-shaped molded product. A method of forming a curable composition into a predetermined shape by extrusion molding, transfer molding or the like, a method of cutting a molded sheet or film into a predetermined shape, a method of secondary processing such as bending, and the like.
It is preferable to use a coating composition when producing a thin-film molded product or a thin-film molded product integrated with a base material.

Examples of the coating method for the coating composition include spin coating method, wipe coating method, spray coating method, squeegee coating method, dip coating method, die coating method, inkjet method, flow coating method, roll coating method, casting method, and Langmuir brojet. Examples include the law and the gravure coat method.

[Cured product of fluorine-containing polymer]
The cured product of the fluorine-containing polymer has no foaming, has high transparency of visible light of 400 nm or more, and has no photodegradation, and is therefore useful as a sealing material or a lens for a high-power LED. In addition, since it has a molecular structure that is essentially non-absorbent at wavelengths of 300 to 400 nm, it is also useful as a translucent encapsulant and a lens for ultraviolet LEDs having emission wavelengths of 365, 380, and 405 nm.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following description. Example 1 is an example, and examples 2 and 3 are comparative examples. The evaluation of each example was carried out according to the method described below.

[Evaluation method]
<Mass average molecular weight>
The mass average molecular weight of the fluoropolymers P1, Q1 and R1 is determined _{by PMMA (polymethyl) by gel permeation chromatography (GPC) using CF 2} ClCF ₂ CHClF (manufactured by Asahi Glass Co., Ltd., trade name: AK-225 kb) as a solvent. Methacrylate) Calculated as a converted molecular weight.

_{<Contents of 3} groups of -COOCH in fluorine-containing polymer>
The content of ₃ -COOCH groups in the fluorine-containing polymer ^{was determined from 19} F-NMR.

<Elastic modulus>
Using the films produced in each example, measurements were taken in the viscoelasticity analysis mode of TMA / EXSTAR SS7100 manufactured by Hitachi High-Tech. Measurement temperature range: -40 ° C to 200 ° C, heating rate: 5 ° C / min, frequency: 0.05Hz.

<UV-LED lighting test>
A constant current power supply (manufactured by Sanhayato Co., Ltd.) was used to energize 300 mA at room temperature without installing a heat sink, and the LED output was measured using a small integrating sphere-fiber multi-channel spectroscope USB2000 (manufactured by Ocean Optics). ..

[unit]
The units referred to in the following production examples are as follows.

[Production Example 1: Production of Fluorine-Containing Polymer P2 Having (a2) Units and (b1) Units]
After vacuum degassing a stainless steel autoclave with a stirrer with an internal volume of 1 L, 11.2 g of perbutyl PV (50 mass% AK-225 kb solution: manufactured by NOF CORPORATION) as a polymerization initiator, CF ₂ = CFOCF ₂ CF ₂ CF ₂ COOCH ₃ 18.7 g, CF ₂ = CFOCF ₂ CF ₂ CF ₃ OCF = CF ₂ 4.2 g, CF ₂ = CFOCF ₂ CF ₂ CF ₃ (hereinafter, also referred to as “PPVE”) 412. 7 g and 517.2 g of AC-2000 were charged. After press-fitting 48.7 g of TFE with stirring, the internal temperature was raised to 60 ° C. to initiate polymerization. Polymerization was carried out for 3 hours while adding TFE into the autoclave while maintaining the pressure in the autoclave at 0.47 MPa. The total amount of TFE charged was 104.9 g.

After cooling the inside of the autoclave, the contents were transferred to a 5 L glass beaker, and 2200 g of AE-3000 was added with stirring to precipitate a fluorine-containing polymer. After removing the supernatant liquid, it was dried to obtain 125.0 g of the fluorine-containing polymer P1. The fluorine-containing polymer P1 was soluble in AK-225cc and AC-2000, and was insoluble in methanol, acetone, and tetrahydrofuran (hereinafter, also referred to as "THF"). The unit composition of the fluorine-containing polymer P1 is unit (a1): unit (c1): unit (d1) = 1.3: 68.8: 29.9 (molar ratio), and the mass average molecular weight is 32,700. there were. The ratio of the unit (b1) is estimated to be a molar ratio of 0.3 from the charging ratio with the unit (a1).

After dissolving 4 g of the fluorine-containing polymer P1 in 22.8 g of AC-2000, 0.17 g of a solution of hydrazine monohydrate (purity 79%, manufactured by Tokyo Kasei Co., Ltd.) diluted 5-fold with methanol was added. It was added and stirred vigorously. Then, after stirring at 40 ° C. for 2 hours, 0.2 g of methanol was added, and the mixture was further heated at 40 ° C. for 5 hours. A part of the reaction solution was cast on a glass plate and the solvent was volatilized by heating at 60 ° C. to produce a film having a thickness of 50 μm. When infrared absorption (IR) was measured ^{, the absorption of 1,794 cm -1} based on C = O of ₃ -COOCH groups in the unit (a1) disappeared, and 1,718 cm based on C = O of _{2 -CONNHN groups.} ^Since the absorption of -1 was newly generated, it was confirmed that the unit (a1) was converted to the unit (a2). When methanol was added to the reaction solution, a precipitate was formed. The precipitate was vacuum dried at 60 ° C. to obtain 3.8 g of the fluorine-containing polymer P2. Since the _three -COOCH groups and the _two -CONNHN groups have the same molecular weight, the mass average molecular weight of the fluorine-containing polymer P2 is the same as that of the fluorine-containing polymer P1 and is the same as that of the fluorine-containing polymer P1.

[Example 1: A cured product of the fluorine-containing polymer P2]
0.7 g of the fluorine-containing polymer P2 was placed on a 5 cm square glass plate and degassed by heating in a vacuum oven at 150 ° C. After returning to normal pressure, a spacer frame with a thickness of 0.5 mm is installed around P2, a fluororesin release film and a glass plate are sequentially placed on it, and a weight of 150 g is further placed on it. It was allowed to stand for a minute. After that, it was taken out from the oven and naturally cooled to obtain an elliptical film having a thickness of 0.5 mm. After the releasing film from the elliptical film was each glass plate peeling was placed thereon, a N ₂ atmosphere, then Atsushi Nobori to 200 ° C., and held for 30 minutes. The temperature was further raised to 250 ° C. and heated for 2 hours. After cooling, the oval film was peeled off from the glass plate on which the oval film was placed to obtain a colorless, transparent, oval-cured film. The light transmittance was measured and found to be 90% at a wavelength of 400 nm and 87% at a wavelength of 365 nm.

When the viscoelasticity of the cured film was measured, a decrease in elastic modulus corresponding to the glass transition temperature (Tg) was observed around 5 ° C, and the rubber-like flat portion was substantially constant up to at least 200 ° C at temperatures above Tg. It was confirmed that the cross-linking reaction occurred by heating at 250 ° C.

A small piece of uncured fluorine-containing polymer P2 film is placed on a cup-shaped aluminum package with a wire-bonded 1W type UV-LED (emission wavelength 365 nm) manufactured by Nitride Semiconductor, and heated and melted at 170 ° C in a vacuum oven. Then, while degassing, it was allowed to flow by its own weight to mold the concave portion of the package. After taken out of the vacuum oven, 200 ° C. in a _{N 2} atmosphere, then heated for 30 minutes, it was sealed in UV-LED by heating for 2 hours curing at further 250 ° C.. When the UV-LED package was soldered to an aluminum wiring board and continuously lit at 300 mA, the output at the start of 365 nm UV was about the same as that of the unsealed package, but the output increased by 15% in about 50 hours. Then, the output level was maintained for 1000 hours.

[Production Example 2: Production of Fluorine-Containing Polymer Q2]
In a stainless steel autoclave with an internal volume of 200 mL, 0.1 g of V601 (manufactured by Wako Pure Chemical Industries, Ltd.) was charged as a polymerization initiator, degassed under reduced pressure, and then CF ₂ = CFOCF ₂ CF ₂ CF ₂ COOCH ₃ 20 g, 40 g of PPVE, and 103 g of AC-2000 were charged. After press-fitting 12 g of TFE while stirring the contents of the autoclave, the internal temperature was raised to 80 ° C. to initiate polymerization. Polymerization was carried out for 6 hours while adding TFE while maintaining the pressure in the autoclave at 0.72 MPa. The total amount of TFE charged was 28.3 g.

After cooling the inside of the autoclave, the contents were transferred to a 500 mL glass beaker, and 200 g of methanol was added with stirring to precipitate a fluorine-containing polymer. After removing the supernatant liquid, it was dried to obtain 20.6 g of the fluorine-containing polymer Q1. The fluorine-containing polymer Q1 was soluble in AK-225cc and AC-2000, and insoluble in methanol, acetone and THF. The composition of the fluorine-containing polymer Q1 is unit (a1): unit (c1): unit (d1) = 8.0: 75.7: 16.3 (molar ratio), and the mass average molecular weight is 21,700. there were. The fluorinated polymer Q1 and hydrazine monohydrate are reacted in the same manner as in Production Example 1 with a total reaction time of 3 hours, and the unit (a2) is 1/2 to the unit (a2) of the unit (a1) of the fluorinated polymer Q1. ) Was generated to obtain a fluorine-containing polymer Q2. The mass average molecular weight of the fluorine-containing polymer Q2 is the same as that of the fluorine-containing polymer Q1.

[Example 2: A cured product of the fluorine-containing polymer Q2]
0.7 g of the fluorine-containing polymer Q2 was placed on a 5 cm square glass plate and degassed by heating in a vacuum oven at 130 ° C. After returning to normal pressure, a spacer frame with a thickness of 0.5 mm is placed around the fluoropolymer Q2, and a fluororesin release film and a glass plate are sequentially placed on the spacer frame, and a weight of 150 g is further placed on the spacer frame. Was placed and allowed to stand for 10 minutes. After that, it was taken out from the oven and naturally cooled to obtain an elliptical film having a thickness of 0.5 mm. After each glass sheet peeling the mold releasing film was placed thereon, which placed on a fluoropolymer, in an N ₂ atmosphere was vigorously bubbling temperature was raised heated to 200 ° C.. Again, in the same manner as above, the fluorine-containing polymer Q2 was heated and degassed at 130 ° C. and then allowed to stand to prepare an uncured elliptical film, and the obtained uncured elliptical film was heated at 150 ° C. for 1 hour. Then, the temperature was further raised to 250 ° C. and heated for 2 hours. After cooling, the elliptical film was peeled off from the glass plate on which the oval film was placed to obtain a transparent cured film having wrinkles and haze on the surface.

Further, an attempt was made to seal using the fluorine-containing polymer Q2 using the same UV-LED as in Example 1, but when molding by heating and melting at 150 ° C., deaeration could not be performed under reduced pressure due to foaming, and bubbles remained. Since it was cured as it was, the output of 365 nm UV was reduced to about half.

[Production Example 3: Production of Fluorine-Containing Polymer R2]
After vacuum degassing a stainless steel autoclave with an internal volume of 1 L, as a polymerization initiator, 4.5 g _{of perbutyl PV, 25.0 g of CF 2} = CFOCF ₂ CF ₂ CF _{2 COOCH 3} , and 407.9 g of PPVE. And 514.2 g of AC-2000 was charged. After press-fitting 48.4 g of TFE with stirring, the internal temperature was raised to 60 ° C. to initiate polymerization. Polymerization was carried out for 4 hours while adding TFE while maintaining the pressure in the autoclave at 0.49 MPa. The total amount of TFE charged was 97.2 g.

After cooling the autoclave, the contents were transferred to a 5 L glass beaker, and 2200 g of AE-3000 was added with stirring to precipitate a fluorine-containing polymer. After removing the supernatant liquid, it was dried to obtain 107.1 g of the fluorine-containing polymer R1. The fluorine-containing polymer R1 was soluble in AK-225cc and AC-2000, and insoluble in methanol, acetone and THF. The unit composition of the fluorine-containing polymer R1 is unit (a1): unit (c1): unit (d1) = 1.7: 67.6: 30.7 (molar ratio), and the mass average molecular weight is 39,400. there were.

After dissolving 4 g of the fluorine-containing polymer R1 in 22.8 g of AC-2000, 0.27 g of a solution obtained by diluting hydrazine monohydrate (purity 79%, manufactured by Tokyo Kasei Co., Ltd.) 5 times with methanol was added. It was added and stirred vigorously. After stirring at 40 ° C. for 2 hours, 0.3 g of methanol was added, and the mixture was further heated at 40 ° C. for 6 hours. A part of the reaction solution was cast on a glass plate and heated at 60 ° C. to volatilize the solvent to produce a film having a thickness of 50 μm, and its infrared absorption (IR) was measured. As a result, the unit (a1) in the absorption of 1,794Cm ^-1 based on C = O of -COOCH ₃ groups and the disappearance of, the new absorption 1,718Cm ^-1 based on C = O of ₂ groups -CONHNH Since it was generated, it was confirmed that the unit (a1) was converted into the unit (a2). When methanol was added to the remaining reaction solution, the polymer precipitated. The precipitated polymer was vacuum dried at 60 ° C. to obtain 3.8 g of the fluorine-containing polymer R2.

[Example 3: A cured product of the fluorine-containing polymer R2]
0.7 g of the fluorine-containing polymer R2 was placed on a 5 cm square glass plate and degassed by heating in a vacuum oven at 150 ° C. After returning the inside of the vacuum oven to normal pressure, a spacer frame having a thickness of 0.5 mm is placed around the fluoropolymer R2, and a fluororesin release film and a glass plate are sequentially placed on the spacer frame, and further from above. A 150 g weight was placed and allowed to stand for 10 minutes. Then, the fluorine-containing polymerization R2 was taken out from the oven and naturally cooled to obtain an elliptical film having a thickness of 0.5 mm as a cured product of the fluorine-containing polymerization R2. After the releasing film from the oval-shaped film to each glass sheet peeling loaded thereon, in an N ₂ atmosphere, it was heated heated to 200 ° C., held for 30 minutes, and heated for 3 hours while the temperature was raised to 250 ° C. .. After cooling, the oval film was peeled off from the glass plate on which the oval film was placed to obtain a colorless, transparent, oval-cured film. When the light transmittance was measured, it was 88% at a wavelength of 400 nm and 80% at 365 nm, and the UV transmittance was slightly lower than that of the cured product of Example 1.

Further, when the viscoelasticity of the obtained cured film was measured, a decrease in elastic modulus corresponding to the glass transition temperature (Tg) was observed around 5 ° C., and a rubber-like flat portion appeared at a temperature of Tg or higher. Since the elastic modulus was slightly lower than that of the cured product of Example 1, it can be seen that the crosslink density was slightly lower.

Similarly to Example 1 using a fluorine-containing polymer R2, 200 ° C. in a _{N 2} atmosphere, then heated for 30 minutes, sealed with UV-LED by heating for 2 hours curing at further 250 ° C.. When energized at 300 mA, the output of 365 nm UV was 10% lower than that of the unsealed one, and after 300 hours of continuous energization, foaming occurred and the output was halved.

Regarding the fluorine-containing polymers of Production Examples 1 to 3 and the cured products of Examples 1 to 3, _{the content of -CONNHN 2} groups, the light transmittance of the cured film, the curing temperature, the presence or absence of foaming at the time of LED sealing, and UV-LED. The results of the lighting test are shown in Table 1.

From the results of Example 1, the fluorine-containing polymer of the present embodiment contains a unit (2) as a branched structure that contributes to the formation of a cross-linking group in addition to the unit (1) that is a cross-linking group, and therefore has melt fluidity. It can be seen that the LED can be sealed without foaming without damaging the above, and the melt moldability is excellent. Further, as a result of a 1000-hour continuous lighting test, it is found that the cured product obtained from the fluorine-containing polymer of the present embodiment is excellent in heat resistance and light resistance. On the other hand, in Example 2 in which the content ratio of the unit (1) is high and the unit (2) is not contained, the curing is performed at a lower temperature than in Example 1, but the curing proceeds when the LED is molded by heating and flowing. It was difficult to suppress foaming. Further, the fluorine-containing polymer of Example 3 having the same content of the unit (1) as that of Example 1 but not containing the unit (2) could be molded without foaming, but foaming occurred during continuous lighting. From this, it can be seen that the heat resistance is inferior due to insufficient cross-linking.

According to the present invention, it is possible to provide a fluorine-containing polymer which is thermosetting and has both melt moldability and heat resistance and UV resistance.
The fluorine-containing polymer of the present embodiment is useful as an optical material, a sealing material for an element, an inorganic EL phosphor dispersant, a material for an optical waveguide, a heat-resistant and chemical-resistant sealing material, an adhesive, and a coating material.
The coating composition of the present embodiment is useful as a mold release agent, an antifouling coating material, a chemical resistant protective coating material, and the like. Since the fluorine-containing polymer of the present invention can be UV-cured, it can be coated on a base material having low heat resistance such as a plastic material.
The cured product of the fluorine-containing polymer of the present embodiment is useful as a light-transmitting encapsulant for UV-LED. It is also used as an underfill material for flip-chip type elements.
The molded product made of a cured product of the fluorine-containing polymer of the present embodiment is useful as a core material or clad material for an optical fiber, a core material or clad material for an optical waveguide, or a material for a lens.
The base material provided with the cured product of the fluorine-containing polymer of the present embodiment is useful as a light emitting element, a semiconductor element, a solar cell element, a short wavelength light emitting element, and the like, and in particular, the light emitting element and the curing of the fluorine-containing polymer. It is useful as a light emitting device having an object.

Claims (11)

A fluorine-containing polymer containing a unit represented by the following formula (1) and a unit represented by the following formula (2).

(In the formula (1), R ^f1 is a fluoroalkylene group or a fluoroalkylene group having an ether oxygen atom between carbon atoms and having two or more carbon atoms, and R ¹ and R ² are independent of each other. It is a hydrogen atom or an alkyl group.)

(In the formula ^{(2), X 1, X} 2, X 3 are each independently a fluorine atom or a hydrogen atom, two ^{Q 2} are each a single bond or an ether oxygen atom ^{independently, R f2} is the number of carbon atoms It is a fluoroalkylene group of 1 to 6 or a fluoroalkylene group having 2 to 25 carbon atoms having an ethereal oxygen atom between carbon-carbon atoms.) The fluorine-containing polymer according to claim 1, wherein at least a part of the unit represented by the formula (1) is − [CF _2- CF (O (CF ₂ ) ₃ CONNHN _{2)] −.} The fluorine-containing polymer according to claim 1 or 2, further comprising a unit derived from fluoroethylene. The fluorine-containing polymer according to any one of claims 1 to 3, further comprising a unit represented by the following formula (3) (excluding a unit derived from fluoroethylene).
-[CX ⁴ X ^5- CY ¹ Y ² ]-... (3)
(In the formula (3), ^{X 4} and ^{X 5} are each independently a hydrogen atom, a fluorine atom or a chlorine atom,
Y ¹ is a hydrogen atom, a fluorine atom or a chlorine atom,
Y ² is a hydrogen atom, a fluoroalkyl group, a fluoroalkyl group having 2 or more carbon atoms having an ether oxygen atom between carbon and carbon atoms, a fluoroalkoxy group, or a carbon having an ether oxygen atom between carbon and carbon atoms. It is a fluoroalkoxy group of several 2 or more. ) The ratio of the units represented by the formula (1) is 0.1 to 20 mol% with respect to the total of the units contained in the fluorine-containing polymer, and the ratio of the units represented by the formula (2) is 0. The fluorine-containing polymer according to any one of claims 1 to 4, which is .05 to 3 mol%. The ratio of the units represented by the formula (1) is 0.1 to 5 mol% with respect to the total of the units contained in the fluorine-containing polymer, and the ratio of the units represented by the formula (2) is 0. The fluorine-containing polymer according to any one of claims 1 to 4, which is .05 to 3 mol%. The fluorine-containing polymer according to any one of claims 1 to 6, which has a mass average molecular weight of 3,000 to 100,000. The fluorine-containing polymer according to any one of claims 1 to 6, which has a mass average molecular weight of 5,000 to 100,000. A method for producing a cured product of a fluorinated polymer, which comprises heating the fluorinated polymer according to any one of claims 1 to 8 at 150 to 300 ° C. A light emitting device comprising a light emitting device and a cured product of the fluorine-containing polymer according to any one of claims 1 to 8. The light emitting device according to claim 10, wherein the light emitting element is a white LED or an ultraviolet LED.