JPH07103197B2 - Method for producing graft copolymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a graft copolymer, and more particularly to a method for producing a graft copolymer excellent in impact resistance and cold resistance.

[Conventional technology]

Polyvinylidene fluoride (hereinafter sometimes abbreviated as “PVdF”) has excellent weather resistance, corrosion resistance, electrical characteristics, workability, and the like, and is therefore used in various applications.

However, since PVdF has a large crystallinity, the residual stress during processing is large, and stress cracks easily occur over time,
In addition, it lacks flexibility and is inferior in impact resistance and cold resistance to other fluororesins. Therefore, in order to improve impact resistance and cold resistance, vinylidene fluoride and other monomers, such as hexafluoropropylene, tetrafluoroethylene,
A method of copolymerizing with methyl methacrylate, butyl acrylate, or the like, or a method of blending PVdF with an acrylic resin or the like has been proposed.

[Problems to be solved by the invention] However, a copolymer obtained by a method of copolymerizing vinylidene fluoride and another monomer is excellent in flexibility, but has a lower melting point and a usable temperature range. And the workability deteriorate. In addition, the composition obtained by the method of blending PVdF with an acrylic resin or the like has transparency,
Although it is excellent in workability and flexibility, it has a drawback that weather resistance and chemical resistance are deteriorated.

Therefore, an object of the present invention is to provide a method for producing a graft copolymer that has the original characteristics of PVdF and is excellent in impact resistance and cold resistance.

[Means for Solving the Problems]

MEANS TO SOLVE THE PROBLEM this invention solves the said subject, (A) General formula (I), (II), (III), (IV) and (V): [Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is a formula: —O—R′—, —NH—R′— [R ′ is an alkylene having 1 to 20 carbon atoms] Base or formula: Wherein R ³ , R ⁴ and R ⁵ may be the same or different and are a monovalent hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a formula: (A plurality of R ^{6 s} may be the same or different and each has 1 to 3 carbon atoms
20 monovalent hydrocarbon monovalent hydrogen groups, n is an integer from 0 to 100, and R ⁷ has the same meaning as R ⁶ , or the following formula: (Wherein R ⁶ and n are as described above). )] [Where A is the following formula: (R ² , R ³ , R ⁴ and R ⁵ are the same as defined above) [A is as above] [A is the same as above] [Wherein R ² , R ³ , R ⁴ and R ⁵ are the same as those in the above general formula (I)] and at least 1 selected from the organosilicon compounds
A polymer obtained by polymerizing a seed, and (B) a monomer containing vinylidene fluoride as an essential component,
(A) / (B) in a weight ratio of 1/99 to 50/50,
By reacting in the presence of a radical polymerization initiator,
It is intended to provide a method for producing a graft copolymer by graft-copolymerizing the monomer of (B) with the polymer of (A).

In the method of the present invention, the polymer as the component (A) is at least one selected from the organosilicon compounds represented by the above general formulas (I), (II), (III) and (IV). It is a mixture. This general formula (I), (II), (II
In I) and (IV), R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, for example, a methyl group, an ethyl group or a propyl group, and R ² is represented by the formula: —O—R′—, NH— R'- [R 'is an alkylene group having 1 to 20 carbon atoms or a formula: Is a group represented by. R ³ , R ⁴ and R ⁵ may be the same or different and are a monovalent hydrocarbon group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group and a phenyl group. An alkoxy group having 1 to 3 carbon atoms, for example, a methoxy group, an ethoxy group, a propoxy group or the like, or a formula: (A plurality of R ^{6 s} may be the same or different and each has 1 to 3 carbon atoms.
20 monovalent hydrocarbon groups, n is an integer from 0 to 100, and R ⁷
Has the same meaning as R ⁶ or the following formula: (Wherein R ⁶ and n are as described above). ) Specific examples of the organic silicon compound represented by the general formula (I), (II), (III), (IV) or (V) include those represented by the following formula. However, in the following formula, Me is a methyl group, Et is an ethyl group, Pr is a propyl group,
Ph represents a phenyl group.

(A) Organic silicon compound represented by formula (I) (B) Organic silicon compound represented by the formula (II) At (C) Organic silicon compound represented by the formula (III) At (D) Organic silicon compound represented by the formula (IV) At (E) Organic silicon compound represented by formula (V) The production of the polymer of the organosilicon compound used as the component (A) in the present invention is not particularly limited and is represented by, for example, the above general formulas (I), (II), (III) and (IV). It can be carried out by polymerizing at least one kind of organic silicon compound in the presence of a radical polymerization initiator according to a conventional method. This polymerization is usually an organic or inorganic peroxide,
Azo compounds, radical employment initiators such as redox initiators Suspension polymerization, emulsion polymerization, solution polymerization or bulk polymerization, etc. are generally performed at a polymerization temperature of 30 to 100 ° C and a polymerization time of about 0.5 to 20 hours. Target.

The monomer containing vinylidene fluoride, which is the component (B), used in the method of the present invention is vinylidene fluoride alone, or vinylidene fluoride and another monomer which is copolymerizable with vinylidene fluoride. It refers to a mixture of monomers including the body. Other monomers copolymerizable with vinylidene fluoride include, for example, other fluorine-based monomers such as tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene; α-olefins such as ethylene and methyl methacrylate. And (meth) acrylic monomers such as butyl acrylate. These other monomers copolymerizable with vinylidene fluoride may be used alone or in combination of two or more with vinylidene fluoride.

The monomer (B) containing vinylidene fluoride as an essential component used in the method of the present invention usually contains about 50% by weight or more, preferably about 70% by weight or more of vinylidene fluoride.

According to the method of the present invention, the component (A) and the component (B) are combined with the component (A).
The weight ratio of / (B) is 1/99 to 50/50, preferably 2/98 to 30 /
This is a method of reacting in the presence of a radical polymerization initiator at a ratio of 70, and graft-copolymerizing the polymer of component (A) with a monomer of which component (B) is vinylidene fluoride as an essential component. When the weight ratio of (A) / (B) is less than 1/99,
The impact resistance and cold resistance of the resulting graft copolymer are not improved, and when it exceeds 50/50, not only the impact resistance and cold resistance are not further improved, but the original characteristics of PVdF are impaired.

The radical polymerization initiator used in the method of the present invention includes organic and inorganic peroxides such as diisopropyl peroxycarbonate, di-n-peroxydicarbonate, heptafluorobutyl peroxide, ammonium persulfate, potassium persulfate; Azo compounds; redox polymerization initiators and the like can be mentioned. These are used alone or in combination of two or more.

The form of graft copolymerization in the method of the present invention is not particularly limited, and generally, the reaction is carried out in a homogeneous system or a heterogeneous system using an appropriate medium. For example, suspension polymerization or emulsion polymerization using a hydrophobic solvent such as water or trichlorofluoroethane as a medium can be performed. In this reaction, it is optional to use a chain transfer agent such as isopropyl alcohol or acetone in order to adjust the molecular weight of the obtained graph copolymer.

The polymerization conditions for the graft copolymer are usually a polymerization temperature of 20 to 10
Polymerization time is 1 to 50 hours at 0 ° C.

In addition, in the method of the present invention, (A) previously produced
It is also possible to use a component polymer and graft-copolymerize it with a monomer containing vinylidene fluoride as an essential component, and to obtain the organosilicon compound represented by the above general formulas (I) to (IV). At least one is polymerized, and then the obtained reaction product containing the polymer of the component (A) is directly added with a monomer containing the vinylidene fluoride of the component (B) as an essential component.
The component (A) may be graft-copolymerized with vinylidene fluoride or another monomer.

Further, in the method of the present invention, it is optional to add to the produced graft copolymer a compounding agent generally compounded with a resin or the like, for example, an ultraviolet absorber, a filler, a colorant or the like. .

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

Example 1 (1) Production of Polymer of Organosilicon Compound In a polymerization vessel having an internal volume of 1 l, 500 g of pure water, 250 g of tris (trimethylsiloxy) methacryloyloxypropylsilane (S-5 shown in the above specific example), lauryl Peroxide 2.
5 g and methyl cellulose 0.25 g were charged and reacted at 80 ° C. for 4 hours. Then, the polymerization system was cooled to terminate the reaction, and the reaction product was dehydrated and dried to obtain semitransparent bead-shaped polymer particles.

(2) Production of Graft Copolymer The polymer obtained in (1) above was placed in a polymerization vessel having an internal volume of 2 liters.
g, pure water 1000 g and methyl cellulose 0.4 g were charged, the system was evacuated, and then vinylidene fluoride 400 g was charged. Then, a solution of 6 g of di-n-peroxydicarbonate dissolved in 60 g of trichlorotrifluoroethane and 12 g of isopropyl alcohol were pressed into the polymerization vessel and reacted at 50 ° C. for 20 hours. After purging the unreacted monomer in the polymerization vessel,
The reaction product was dehydrated and dried to obtain 380 g of a white powdery graft copolymer.

The obtained graft copolymer was melted and extruded into a round bar at a cylinder temperature of 180 to 200 ° C. and a die temperature of 220 ° C. using a 20 mmφ extruder, and cut into pellets by a pelletizer.

Next, using a 15t injection molding machine, this pellet was made into a test piece of 90 × 22 × 4 mm at a cylinder temperature of 230 to 260 ° C and a mold temperature of 40 ° C, and this test piece was subjected to Izod impact according to ASTM-D256. The strength was measured according to JIS K7216 and the brittle temperature. The results are shown in Table 1.

Examples 2 to 5 In each example, instead of the tris (trimethylsiloxy) methacryloyloxypropylsilane in (1) of Example 1, the organosilicon compounds shown in Table 1 were used to prepare polymers of organosilicon compounds. A graft copolymer was produced in the same manner as in Example 1 except that the Izod impact strength and embrittlement temperature were measured.

The results are shown in Table 1.

Comparative Example 1 With respect to a vinylidene fluoride homopolymer, the Izod impact strength and the brittle temperature were measured in the same manner as in Example 1.

The results are shown in Table 1.

Example 6 A polymerization vessel having an internal volume of 6 l was charged with 2.5 g of pure water, 200 g of tris (trimethylsiloxy) methacryloyloxypropylsilane (S-5 shown in the above specific example), 12 g of diisopropyl peroxydicarbonate and 1.2 g of methyl cellulose. After replacing the inside of the polymerization system with nitrogen, the reaction was carried out at 50 ° C. for 2 hours. After that, the inside of the polymerization system was evacuated and charged with 360 g of trichlorotrifluoroethane and 1200 g of vinylidene fluoride,
The temperature was raised to 0 ° C. and the reaction was continued for 15 hours. After cooling, the unreacted monomer remaining in the polymerization system was purged, and the reaction product was dehydrated and dried to give a white powdered graft copolymer 1180 g.
Got

With respect to the obtained graft copolymer, Izod impact strength and embrittlement temperature were measured in the same manner as in Example 1.

The results are shown in Table 2.

Examples 7 and 8 Example 6 except that the amount of tris (trimethylsiloxy) methacryloxypropylsilane used was changed to that shown in Table 1.
A graft copolymer was produced in the same manner as in, and the Izod impact strength and the brittle temperature were measured.

The results are shown in Table 2.

[Effects of the Invention] According to the method of the present invention, it is possible to obtain a graft copolymer that is provided with a swan originally possessed by PVdF and is excellent in impact resistance and cold resistance.

Claims (1)

[Claims] 1. A general formula (I), (II), (III),
(IV) and (V): [Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is a formula: —O—R′—, —NH—R′— [R ′ is an alkylene having 1 to 20 carbon atoms] Base or formula: Wherein R ³ , R ⁴ and R ⁵ may be the same or different and are a monovalent hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a formula: (A plurality of R ^{6 s} may be the same or different and each has 1 to 3 carbon atoms.
20 monovalent hydrocarbon groups, n is an integer from 0 to 100, and R ⁷
Has the same meaning as R ⁶ or the following formula: (Wherein R ⁶ and n are as described above). )] [Where A is the following formula: (R ² , R ³ , R ⁴ and R ⁵ are the same as defined above) [A is as above] [A is the same as above] [Wherein R ² , R ³ , R ⁴ and R ⁵ are the same as those in the above general formula (I)] and at least 1 selected from the organosilicon compounds
A polymer obtained by polymerizing a seed, and (B) a monomer containing vinylidene fluoride as an essential component,
(A) / (B) in a weight ratio of 1/99 to 50/50,
By reacting in the presence of a radical polymerization initiator,
A method for producing a graft copolymer in which the monomer of (B) is graft-copolymerized with the polymer of (A).