JPH0812839A - Method for producing fluorinated thermoplastic elastomer - Google Patents

Abstract

PURPOSE:To obtain the subject elastomer, excellent in various mechanical characteristics and useful for moldings such as tubes by carrying out the kneading reaction of two kinds of polymers having specific functional groups with a compound having a functional group reactive with the respective functional groups under melting conditions. CONSTITUTION:This method for producing a fluorinated thermoplastic elastomer is to knead (A) a polymer having functional groups (X), <=10 deg.C glass transition temperature and >=40wt.% fluorine content with (B) a polymer having functional groups (Y), >=150 deg.C melt temperature and >=40wt.% fluorine content in the presence of (C) a compound having a functional group (Z<1>) reactive with the functional groups (X) and a functional group (Z<2>) reactive with the functional groups (Y) under melting conditions and react the functional groups (X) with (Z<2>) and further react the functional groups (Y) with (Z<2>). Furthermore, the weight ratio of the components (A)/(b) is preferably (95/5) to (30/70). The functional groups (X), (Y), (Z<1>) and (Z<2>) are preferably selected from epoxy, amino, hydroxyl groups, carboxyl, thiol groups, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a fluorinated thermoplastic elastomer.

[0002]

2. Description of the Related Art Thermoplastic elastomers have properties similar to vulcanized rubbers, but unlike vulcanized rubbers, they do not require a vulcanization step and can be molded and processed like resins, and various materials have been developed and used in a wide range of fields. (“Synthetic Resin” 39 (8), 3,
(See 1993).

Regarding a fluorinated thermoplastic elastomer having a fluororubber as a soft segment and a fluororesin as a hard segment, a rubber component monomer is polymerized in the presence of a perfluoroalkyl iodo compound, and then a resin component monomer is polymerized to obtain a block polymer. After the iodine transfer polymerization method (Japanese Patent Publication No. 61-49327) to obtain a peroxy compound having an unsaturated bond and a rubber component monomer,
Polymer radical method to obtain a graft polymer by polymerizing a resin component monomer at the decomposition temperature of the peroxy group in the polymer (Japanese Patent Publication No. 62-32424), and kneading a blend of fluororubber and fluororesin to crosslink the fluororubber. The vulcanization method (JP-A-4-108845) is also known.

[0004]

However, when a block polymer or a graft polymer is synthesized by an iodine transfer polymerization method or a polymer radical method, not a little fluororesin portion and fluororubber portion which are not chemically bonded remain,
Therefore, the obtained block polymer or graft polymer has a large compression set at a temperature of 100 ° C. or higher, and its applicability to applications in which the excellent heat resistance of the fluorine-based material is utilized is not sufficient. Further, even in the dynamic vulcanization method, there is a problem that the high temperature characteristics and molding processability are still insufficient.

An object of the present invention is to provide a method for producing a fluorinated thermoplastic elastomer having excellent mechanical properties.

[0006]

The present invention provides a functional group (X).
With a glass transition temperature of 10 ° C or less and a fluorine content of 4
The polymer (A) of 0% by weight or more and the polymer (B) having a functional group (Y) and a melting temperature of 150 ° C. or more and a fluorine content of 40% by weight or more are reacted with the functional group (X). Functional group (Z
¹ ) and a compound (C) having a functional group (Z ² ) which reacts with the functional group (Y), and melt-kneaded to obtain a functional group (X)
And a functional group (Z ¹ ) are reacted with each other, and a functional group (Y) and a functional group (Z ² ) are reacted with each other.

Examples of the polymer (A) include polymers having tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, hexafluoropropylene, perfluoro (alkyl vinyl ether) as a polymerization component, Hydrocarbon monomers such as ethylene, propylene, isobutylene and alkyl vinyl ether may be copolymerized as appropriate.

Preferred specific examples of the polymer (A) include vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer, and tetrafluoroethylene / propylene copolymer. Coalescence, tetrafluoroethylene / vinylidene fluoride / propylene copolymer, tetrafluoroethylene / vinylidene fluoride / perfluoro (alkyl vinyl ether) copolymer and tetrafluoroethylene / perfluoro (alkyl vinyl ether)
Examples thereof include system copolymers.

The molecular weight of the polymer (A) is not particularly limited, but the Mooney viscosity ML _{1 + 4} (100 which is a measure of the molecular weight).
A temperature range of 5 to 150, particularly 10 to 120, is preferably adopted. If the Mooney viscosity is too low, the rubber elasticity is not sufficient, and if it is too high, the moldability decreases.

The functional group (X) contained in the polymer (A) is an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a thiol group, an isocyanate group, an acid anhydride group, an alkoxysilyl group or a silyl halide group. , Halogen atoms and unsaturated double bond groups are preferred. To introduce the functional group (X) into the polymer (A), a method of copolymerizing a monomer having the functional group (X) with a polymerization component such as the above fluoroolefin is usually used.

The glass transition temperature of the polymer (A) (hereinafter, T
_g ) is 10 ° C. or less. When T _g is higher than this, the rubber elasticity of the fluorinated thermoplastic elastomer becomes insufficient and the resin becomes resin-like at room temperature. It is particularly preferable that T _g is 0 ° C. or lower.

The fluorine content of the polymer (A) is 40% by weight.
That is all. If it is lower than this range, the heat resistance, solvent resistance and oil resistance of the fluorinated thermoplastic elastomer will be insufficient.
The fluorine content of the polymer (A) is preferably 50% by weight or more.

Examples of the polymer (B) include polymers having tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, hexafluoropropylene, perfluoro (alkyl vinyl ether) as a polymerization component, Hydrocarbon monomers such as ethylene, propylene, isobutylene and alkyl vinyl ether may be copolymerized as appropriate.

Specific preferred examples of the polymer (B) include tetrafluoroethylene-based polymers, tetrafluoroethylene / hexafluoropropylene-based copolymers, tetrafluoroethylene / perfluoro (alkyl vinyl ether) -based copolymers and tetrafluoroethylene. Examples thereof include ethylene / ethylene-based copolymers, chlorotrifluoroethylene-based polymers and vinylidene fluoride-based polymers.

The molecular weight of the polymer (B) is not particularly limited, but the volume flow rate, which is a measure of the molecular weight, is 10 to 5000 mm.
^{The range of 3} / sec, particularly 50 to 3000 mm ³ / sec is suitable. The volume flow rate was measured using a Koka type flow tester at a temperature of 300 ° C. and a load of 30 kg / cm ² and a diameter of 2.
It is represented by the volume of the polymer (B) flowing out from a nozzle having a length of 1 mm and a length of 8 mm in a unit time. If the volume flow rate is too low, the moldability is insufficient, and if it is too high, the strength is reduced.

The functional group (Y) contained in the polymer (B) is
It may be the same as or different from the functional group (X). Examples of the functional group (Y) include an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a thiol group, an isocyanate group, an acid anhydride group, an alkoxysilyl group, a silyl halide group, a halogen atom and an unsaturated double bond group. Is preferred. The introduction of the functional group (Y) into the polymer (B) is carried out by a method of introducing a monomer having the functional group (Y) by copolymerizing it with a polymerization component such as the above fluoroolefins.

The melting temperature of the polymer (B) (hereinafter referred to as T _m ) is 150 ° C. or higher. When T _m is lower than this, the heat resistance of the fluorinated thermoplastic elastomer is lowered. T _m
Is particularly preferably 200 ° C. or higher.

The fluorine content of the polymer (B) is 40% by weight.
That is all. If it is lower than this range, the heat resistance, solvent resistance and oil resistance of the fluorinated thermoplastic elastomer will be insufficient.
The fluorine content of the polymer (B) is particularly preferably 50% by weight or more.

The compound (C) includes a functional group (Z ¹ ) which reacts with the functional group (X) and a functional group (Z) which reacts with the functional group (Y).
² ). The functional group (Z ¹ ) and the functional group (Z ² ) include epoxy group, amino group, hydroxyl group, carboxyl group, thiol group, isocyanate group, acid anhydride group, alkoxysilyl group, halogenated silyl group, halogen atom. And unsaturated double bond groups are preferred. The functional group (Z ¹ ) and the functional group (Z ² ) are preferably the same type of functional group, but may be different types of functional groups.

As the compound (C), a low molecular weight compound having two or more functional groups is preferable, but an oligomer or a high molecular weight compound may be used. If the number of functional groups is too large, crosslinking may occur during the reaction and the thermoplasticity may be lost. A compound having 2 to 5 functional groups is preferable.

Preferred specific examples of the compound (C) are pyromellitic acid, trimellitic acid, benzophenonetetracarboxylic acid, 2,2-bis (4-aminophenyl) propane and 2,2-bis (4-hydroxyphenyl). Propane, 2,2-bis (4-aminophenyl) -1,1,
1,3,3,3-hexafluoropropane, bisphenol A diglycidyl ether and the like can be mentioned.

The weight ratio of polymer (A) / polymer (B) is
Usually, 95/5 to 30/70 is applied. If the ratio of the polymer (A) is too high, the strength of the elastomer becomes insufficient, and if it is too low, the rubber elasticity becomes insufficient. The weight ratio of polymer (A) / polymer (B) is 90/1.
The range of 0 to 50/50 is more preferable.

The amount of the compound (C) added is 0.1 to 20 relative to 100 parts by weight of the total of the polymer (A) and the polymer (B).
A range of parts by weight is preferred. When the ratio of the compound (C) is too high, the rubber elasticity of the fluorinated thermoplastic elastomer is lowered, and the heat resistance, solvent resistance and oil resistance are insufficient. If it is too small, the reaction between the functional group (Z ¹ ) in the compound (C) and the functional group (X) in the polymer (A), and the reaction between the functional group (Z ² ) in the compound (C) and the polymer The reaction with the functional group (Y) in (B) becomes insufficient.

Content of the functional group (X) in the polymer (A),
And the content of the functional group (Y) in the polymer (B) is 10 ^-7 to 10 ^-1 equivalent / g-polymer, particularly 10 ^-6 to
It is preferably in the range of 10 ^-2 equivalent / g-polymer.
If the amount is too small, the reaction does not proceed sufficiently, and the strength of the obtained elastomer is not sufficient, and if the amount is too large, the elastomer is crosslinked due to the reaction to lose thermoplasticity, and the elongation at break becomes small.

In the production of the fluorinated thermoplastic elastomer of the present invention, a polymer reaction in which the polymer (A), the polymer (B) and the compound (C) are kneaded and reacted under a melting condition is adopted. In this polymer reaction, the functional group (Z ¹ ) reacts with the functional group (X), and the functional group (Z ² ) reacts with the functional group (Y). The elastomer produced by the reaction includes the polymer (A) and the polymer (B) via the compound (C).
And are chemically bonded to each other, and have the rubber elasticity of the polymer (A) and the mechanical properties of the resin of the polymer (B).

This polymer reaction is usually carried out at 160 ° C to 350 ° C using a high shear type kneader such as a twin screw extruder. In order to accelerate the reaction, it is preferable to carry out kneading at high temperature and high shear for a long time. Further, an accelerator such as an amine is added as necessary to accelerate the effect. Also, a method of carrying out the reaction in the presence of a solvent can be adopted, but it is necessary to remove the solvent after the reaction, so a method of melt-kneading without a solvent is preferable.

When the functional group (X) and the functional group (Y) are at the ends of the polymer (A) and the polymer (B), respectively, and the compound (C) is bifunctional, the resulting elastomer is a block type. . Further, in the case of a polymer having a functional group on the side chain and a polymer having a functional group at the terminal, it is a graft type.
When polymers having a functional group in the side chain are reacted with each other, they are crosslinked, but when the content of the functional group is not high, the crosslinking density can be lowered, and flow at high temperature to maintain molding processability. It is a mixed block / graft type. Block type and polymer (A) in which functional groups are present at both ends of the polymer (A) and at one or both ends of the polymer (B)
The graft type having a side chain of 1) and one end or both ends of the polymer (B) is excellent in strength and heat resistance and is preferably used.

As the combination of the functional group (X) and the functional group (Y) and the functional group (Z ¹ ) and the functional group (Z ² ), for example, the functional group (X) and the functional group (Y) are epoxy groups, In the case of an amino group, the functional group (Z ¹ ) and the functional group (Z ² ) are carboxyl groups, and when the functional group (X) and the functional group (Y) are an isocyanate group or an acid anhydride group, A hydroxyl group is preferably used as the functional group (Z ¹ ) and the functional group (Z ² ).

The fluorinated thermoplastic elastomer obtained in the present invention can be used in various fields in which heat resistance, chemical resistance, oil resistance, weather resistance, hygiene, insulation and the like are required.
Specific examples include tubes, hoses, packings, diaphragms, rolls, O-rings, gaskets, films, coating materials, sealing materials, electric wires, and adhesives.

[0030]

【Example】

[Reference Example 1] 1094 g of trichlorotrifluoroethane (hereinafter referred to as R113) and 0.65 g of I (CF ₂ ) ₄ I were added to a 1-liter stainless steel autoclave.
After charging 10.8 g of (nonafluorobutyl) ethylene and 8.8 g of t-butylperoxyisobutyrate (hereinafter referred to as PBIB), the mixture was cooled with liquid nitrogen and deaerated. Next, 130 g of tetrafluoroethylene and 3.17 g of ethylene were charged and the temperature was raised to 65 ° C. to start polymerization.

Tetrafluoroethylene / ethylene = 60/40 (molar ratio) so that the pressure becomes constant by continuing stirring.
The mixed monomer gas of was charged. After 7.4 hours, the residual monomer was purged to terminate the polymerization, and 1.4 kg of a slurry having a copolymer concentration of 6% by weight was obtained. The copolymer has a polymerization unit composition of tetrafluoroethylene / ethylene / (nonafluorobutyl) ethylene having iodine bonded at both ends of 5
It was 8/39/3 (molar ratio).

800 g of the above slurry, 9.0 g of allyl glycidyl ether, and 5 g of PBIB were charged into a 1 liter stainless steel autoclave, cooled with liquid nitrogen and deaerated, charged with nitrogen gas to 1 atm, and heated to 60 ° C. And reacted for 5 hours. The obtained copolymer was repeatedly washed with R113 and then vacuum dried to a volume flow rate of 2000.
mm ³ / sec, T _m of 220 ° C., glycidyl group bonded to both ends and glycidyl group content of 6 × 10 ⁻⁵ equivalent / g-polymer tetrafluoroethylene / ethylene / nonafluorobutylethylene copolymerization 35 g of combined (II) was obtained.

Reference Example 2 500 cm ³ of ion-exchanged water and 4 g of C ₈ F ₁₇ CO ₂ NH ₄ as an emulsifier were charged in a 1 liter stainless steel autoclave and deaerated, and then perfluoro (propyl vinyl ether) (hereinafter PPVE) was used.
Was added), 9.3 g of I (CF ₂ ) ₄ I, 7 g of tetrafluoroethylene and 0.1 g of K ₂ S ₂ O ₈ were charged, and the temperature was raised to 50 ° C. to initiate polymerization.

Tetrafluoroethylene / PPVE = 60/40 (molar ratio) so that the pressure becomes constant by continuing stirring.
The mixture was added sequentially. After 40 hours, the monomers were purged to terminate the polymerization. The obtained latex is salted out with a saline solution, washed with water and dried to have a CF ₂ I group at the end,
_{1 + 4} (100 ℃) is 25, tetrafluoroethylene / P
176 g of a copolymer having a PVE polymerization unit composition of 60/40 (molar ratio) was obtained.

80 g of the copolymer, 16 g of allyl glycidyl ether, 5 g of PBIB, 1 kg of R113
Was charged into a 1-liter stainless steel autoclave, cooled with liquid nitrogen and deaerated, charged with nitrogen gas to 1 atm, and then reacted at 60 ° C. for 5 hours. The obtained copolymer was repeatedly aggregated with methanol and washed repeatedly, and then dried in a vacuum, T _g was 0 ° C., CF ₂ I groups at both ends disappeared, glycidyl groups were bonded, and glycidyl group content was 2 ×. A copolymer (IV) of 10 ⁻⁴ equivalent / g-polymer was obtained.

[Example 1] The polymer unit composition of tetrafluoroethylene / propylene / glycidyl vinyl ether was 55.5 / 43.5 / 1.0 (molar ratio), and the Mooney viscosity ML _{1 + 4} (100 ° C) was 50, 70 g of copolymer (I) having T _g of −2 ° C. and glycidyl group content of 1.3 × 10 ⁻² equivalent / g-polymer, copolymer (II) 30 of Reference Example 1
g, benzophenone tetracarboxylic acid (hereinafter, compound
(VI)) 2.8g 250 in Labo Plastomill
The composition (a) was obtained by melt-kneading under conditions of ° C × 100 rpm × 30 minutes.

As a result of extracting 10 g of the composition (a) with a Soxhlet extractor using tetrahydrofuran as a solvent for 24 hours, 2.3 g of an extract mainly composed of the copolymer (I) was obtained. From this, it was found that the composition (a) was a graft elastomer in which the glycidyl groups of the copolymer (I) and the copolymer (II) were reacted with the carboxyl group of the compound (VI) and bonded.

Composition (a) is 300 ° C., pressure is 150 kg
A sheet was prepared by pressing at 3 cm / cm ² for 3 minutes, and its mechanical properties were evaluated. As a result, the breaking strength was 295 kg / cm ² , the breaking elongation was 400%, and the sheet hardness (JIS-K6253) was A88. By reacting the compound (I) and the copolymer (II) with the compound (VI), an elastomer having the rubber elasticity of the copolymer (I) and the mechanical strength of the copolymer (II) was obtained. .

Comparative Example 1 Instead of the copolymer (I), the polymer unit composition of tetrafluoroethylene / propylene was 5
6/44 (molar ratio), ML _{1 + 4} (100 ° C) is 110,
A composition (b) was obtained in the same manner as in Example 1 except that 70 g of the copolymer (III) having T _g of −3 ° C. was used. Soxhlet extraction of 10 g of the composition (b) in the same manner as in Example 1 resulted in 6.1 g of an extract consisting of the copolymer (III), and the copolymer (III) and the polymer (II) were reactively bonded. I found that I didn't.

[Example 2] The composition (c) was obtained by melt-kneading in the same manner as in Example 1 except that 50 g of the copolymer (I) and 50 g of the copolymer (II) were used. Created. The sheet had a breaking strength of 330 kg / cm ² , a breaking elongation of 370%, and a hardness (JIS-K6253) of A92.

Example 3 60 g of copolymer (IV), 40 g of copolymer (II) and 1.5 g of compound (VI) were melt-kneaded in the same manner as in Example 1 to obtain a composition (d). Later, a press sheet was created. The sheet has a breaking strength of 125 kg / cm.
² , the breaking elongation was 320%, and the hardness (JIS-K6253) was A78.

[Example 4] 60 g of the copolymer (I), the polymerization unit composition of tetrafluoroethylene / ethylene / glycidyl vinyl ether was 59 / 39.5 / 1.5 (molar ratio), and the volume flow rate was 120 mm ³ / sec. , T _m is 230 ° C,
40 g of copolymer (V) having a glycidyl group content of 1.25 × 10 ⁻⁴ equivalent / g-polymer, 1.1 g of compound (VI)
After melt kneading in the same manner as in Example 1 to obtain the composition (e), a press sheet was prepared. The sheet has a breaking strength of 32
5 kg / cm ² , breaking elongation 345%, hardness (JIS-K
6253) was A91.

[0043]

EFFECT OF THE INVENTION A fluorinated thermoplastic elastomer having excellent mechanical properties at high temperature is obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruhisa Miyake 1150, Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa Asahi Glass Co., Ltd. Central Research Laboratory

Claims (7)

[Claims] 1. A glass transition temperature of 10 having a functional group (X).
Polymer (A) having a fluorine content of 40% by weight or more at ℃ or below
And a functional group (Z ¹ ) which reacts with the functional group (X) a polymer (B) having a functional group (Y) and a melting temperature of 150 ° C. or higher and a fluorine content of 40% by weight or higher, and a functional group ( Y) is melt-kneaded in the presence of a compound (C) having a functional group (Z ² ) to react the functional group (X) with the functional group (Z ¹ ), and the functional group (Y) and the functional group A method for producing a fluorinated thermoplastic elastomer, which comprises reacting (Z ² ). 2. A polymer (A) / polymer (B) weight ratio of 9
The method for producing a fluorinated thermoplastic elastomer according to claim 1, which is 5/5 to 30/70. 3. The polymer (A) is vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer, tetrafluoroethylene / vinylidene fluoride /
From propylene-based copolymers, tetrafluoroethylene / propylene-based copolymers, tetrafluoroethylene / vinylidene fluoride / perfluoro (alkyl vinyl ether) -based copolymers and tetrafluoroethylene / perfluoro (alkyl vinyl ether) -based copolymers The method for producing a fluorinated thermoplastic elastomer according to claim 1 or 2, which is at least one selected from the group consisting of: 4. The polymer (B) is a tetrafluoroethylene-based polymer, a tetrafluoroethylene / hexafluoropropylene-based copolymer, a tetrafluoroethylene / perfluoro (alkyl vinyl ether) -based copolymer, a tetrafluoroethylene / ethylene. 2. At least one selected from the group consisting of copolymers, chlorotrifluoroethylene polymers and vinylidene fluoride polymers.
4. The method for producing a fluorinated thermoplastic elastomer according to any one of 3 to 3. 5. The functional group (X) and the functional group (Y) are epoxy group, amino group, hydroxyl group, carboxyl group, thiol group, isocyanate group, acid anhydride group, alkoxysilyl group, silyl halide group, halogen. A selected from the group consisting of an atom and an unsaturated double bond group.
4. The method for producing a fluorinated thermoplastic elastomer according to any one of 4 above. 6. The functional group (Z ¹ ) and the functional group (Z ² ) are epoxy group, amino group, hydroxyl group, carboxyl group, thiol group, isocyanate group, acid anhydride group, alkoxysilyl group, silyl halide group. A halogen atom and an unsaturated double bond group.
5. The method for producing a fluorinated thermoplastic elastomer according to any one of 5 to 5. 7. The content of the functional group (X) in the polymer (A),
And the content of the functional group (Y) in the polymer (B) is in the range of 10 ^-7 to 10 ^-1 equivalent / g-polymer, respectively, of the fluorinated thermoplastic elastomer according to claim 1. Production method.