JP2000044755A - Copolymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copolymer compsn. which has a good org. peroxide vulcanizability and a good storage stability by using a tetrafluoroethylene- propylene-vinylidene fluoride copolymer which has a low content of vinylidene fluoride-derived units and contains unsatd. bonds easily introducible thereinto. SOLUTION: This compsn. contains a copolymer which comprises 35-65 mol.% tetrafluoroethylene units, 20-50 mol.% propylene units, and 0.5-15 mol.% vinylidene fluoride units and has carbon-carbon unsatd. bonds, an org. onium compd., an org. peroxide, and a metal oxide or hydroxide, The copolymer pref. has a Mooney viscosity ML1+10 (121 deg.C) of 5-150 and can be produced by bulk polymn., suspension polymn., emulsion polymn., or the like Pref., carbon-carbon double bonds are introduced into the copolymer by treating in the presence of a basic substance (e.g. an org. amine) or an acidic substance (e.g. an org. acid) at 30-130 deg.C for several min to several hr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copolymer composition having good vulcanizability of an organic peroxide and capable of obtaining a vulcanizate having good heat resistance and oil resistance.

[0002]

2. Description of the Related Art Tetrafluoroethylene (hereinafter referred to as TFE)
) -Propylene (hereinafter, referred to as P) -vinylidene fluoride (hereinafter, referred to as VdF) copolymers are excellent in engine oil resistance and are therefore suitably used for automobile parts such as oil seals. In particular, the TFE-P-VdF copolymer having a polymerized unit content based on VdF of 15 mol% or less is used for an engine oil containing a large amount of an amine-based additive in accordance with the performance improvement of the engine oil. It is known to exhibit excellent durability. It is disclosed that when vulcanizing a TFE-P-VdF copolymer with an organic peroxide, a specific organic quaternary phosphonium compound or an organic quaternary ammonium compound is an effective vulcanization accelerator (Japanese Patent Application Laid-Open No. HEI 9-258572). 6
-116449, JP-A-6-116450).

As a method for improving the dispersibility of these vulcanization accelerators in a composition, a vulcanization accelerator such as tetrabutylammonium hydroxide having a good dispersibility can be used. It is disclosed that a dispersant such as alcohol is used in combination (JP-A-8-231803 and JP-A-8-295776). However, the dispersion of the vulcanization accelerator was improved, and the scorch stability during storage was sometimes reduced.

[0004] JP-B-61-43382, JP-B-1-15
No. 530 discloses a method in which unsaturated bonds are introduced into a copolymer obtained by copolymerizing VdF to enable vulcanization of an organic peroxide, but these steps are extremely complicated and economically problematic. There is. Further, the content of polymerized units based on VdF is 1
It does not describe a TFE-P-VdF copolymer of 5 mol% or less.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide Vd
A TFE-P-VdF copolymer in which the content of polymerized units based on F is small, an unsaturated bond is easily introduced into the polymer, and the organic peroxide vulcanization is good and the storage stability is good. It is to provide a polymer composition.

[0006]

The present invention provides (A) TFE
35 to 65 mol% of polymer units based on P, 20 to 50 mol% of polymer units based on P, and 0.5 to 15 mol% of polymer units based on VdF. A copolymer having a carbon unsaturated bond, (B) an organic onium compound, (C) an organic peroxide, and (D)
A copolymer composition comprising at least one selected from metal oxides and metal hydroxides.

The proportion of polymerized units based on TFE in the copolymer of component (A) is 35 to 65 mol% in order to provide good heat resistance and chemical resistance, and more preferably 45 to 65 mol%.
64 mol%. The proportion of the polymerized unit based on P is from 20 to 5 to give a vulcanizate having good heat resistance and chemical resistance.
0 mol%, and more preferably 35 to 50 mol%. The proportion of polymerized units based on VdF is from 0.5 to 15 to give vulcanizates with very good engine oil resistance.
Mol%, more preferably 0.5 to 10 mol%. Therefore, a preferred copolymer in the present invention is
The ratio of each polymerized unit of TFE, P and VdF is 45 to 64
Mol%, 35 to 50 mol%, and 0.5 to 10 mol%.

The Mooney viscosity ML _{1 + 10} (12) which is an index of the molecular weight of the copolymer of the component (A) in the composition of the present invention.
1 ° C.) is not particularly limited, but is preferably in the range of 5 to 150, particularly preferably 10 to 150, for kneading when producing the composition.
A range of 100 is preferred.

For the production of the copolymer of the component (A), various polymerization systems such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization can be adopted. Catalytic polymerization using a radical initiator, ionizing radiation A legal method, a redox polymerization method, or the like can be appropriately employed.

When only the component (A) is simply heat-treated as a treatment condition for introducing a carbon-carbon unsaturated bond into the copolymer molecule of the component (A), the heat treatment condition is not particularly limited, but is preferably 50 to 400. The temperature is preferably about several seconds to several days at about ° C. The higher the temperature, the shorter the heat treatment time. When heat-treating in the presence of a basic substance or an acidic substance,
The temperature is preferably about 130 ° C. for several minutes to several hours.

As acidic substances, organic acids such as acetic acid and maleic acid, inorganic acids such as sulfuric acid and nitric acid, Lewis acids such as aluminum chloride, phenols, and as basic substances, organic amine compounds, organic phosphine compounds and organic onium compounds ,
Examples include sodium hydroxide, calcium hydroxide, alkoxides of alkali metals, and derivatives of these compounds. The effect is exhibited when the usage amount of the basic substance or the acidic substance is several ppm to several weight% with respect to the component (A).

Further, a carbon-carbon unsaturated bond can be introduced by a known method. By introducing a carbon-carbon unsaturated bond into the copolymer molecule, the organic peroxide vulcanization properties and the scorch stability during storage can be improved.

The carbon-carbon unsaturated bond is identified by having a remarkable absorption in the infrared absorption spectrum in the wave number range of 1700 to 1750 cm ^-1 . Here, having a remarkable absorption in a wave number range of 1700 to 1750 cm ^-1 means that in a measurement of an infrared absorption spectrum, when a 100 μm-thick sample made of a copolymer alone is used, the absorbance is 0.002 or more. Absorption peak is wave number 1700-1
It means that it exists in the range of 750 cm ^-1 .

The organic onium compound (B) acting as a vulcanization accelerator includes an organic ammonium compound,
Examples thereof include an organic phosphonium compound, an organic iminium compound, an organic aminophosphonium compound, and an organic sulfonium compound, and the following organic ammonium compounds and organic phosphonium compounds can be preferably used.

Organic ammonium compounds: tetrabutylammonium bromide, tetramethylammonium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium hydroxide, trioctylmethylammonium hydroxide,
Tridodecylmethyl ammonium bromide, 8-benzyl-
1,8-diazabicyclo [5.4.0] undec-7-
Enium chloride, benzyltrimethylammonium chloride, 1,8-diazabicyclo [5.4.0] undeca-
7-ene p-toluenesulfonic acid and the like.

Organic phosphonium compounds: tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium benzotriazolate, tributylbenzylphosphonium chloride and the like.

The above components (B) may be used alone or in combination of two or more. The effect as a vulcanization accelerator can be enhanced by using a dispersion such as water or alcohol.

The amount of the component (B) used (the total amount used when two or more kinds are used) is 0.1% per 100 parts by weight of the copolymer.
It is preferably from 10 to 10 parts by weight, particularly preferably from 0.2 to 3 parts by weight. 0.
If the amount is less than 1 part by weight, it is difficult to obtain sufficient vulcanization density and vulcanization physical properties.

Examples of the organic peroxide serving as the vulcanizing agent (C) include peroxyketals, dialkyl peroxides, diacyl peroxides, peroxyesters, and hydroperoxides. Specific organic peroxides include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5
-Dimethyl-2,5-bis (t-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, α, α′-bis (t-butylperoxy) Oxy) -p-diisopropylbenzene, 1,1
-Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane and the like. Of these,
α, α′-bis (t-butylperoxy) -p-diisopropylbenzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and the like can be preferably used. The amount of the component (B) used is preferably 0.5 to 10 parts by weight, particularly preferably 1 to 5 parts by weight, per 100 parts by weight of the copolymer.

In the composition of the present invention, a vulcanization aid usually used for peroxide vulcanization may be used. As the vulcanization aid, a compound having two or more unsaturated bonding groups, for example, a polyallyl compound, a dimethacrylate compound, a divinyl compound, a polybutadiene and the like are used. In particular, polyallyl compounds such as triallyl isocyanurate and triallyl cyanurate can be preferably used. These vulcanization aids are used in an amount of 20 per 100 parts by weight of the copolymer.
It is preferably at most 10 parts by weight, particularly preferably at most 10 parts by weight.

The metal oxide or metal hydroxide serving as the component (D) acting as an acid acceptor is preferably an oxide or hydroxide of a divalent metal such as magnesium, calcium, lead, and zinc. Lithium hydroxide or the like can also be used.
Two or more types of component (D) may be used in combination. The use amount of the component (D) (the total use amount when two or more kinds are used) is preferably 1 to 50 parts by weight, particularly preferably 2 to 30 parts by weight, per 100 parts by weight of the copolymer.

The composition of the present invention may contain carbon black, fine silica,
Reinforcing agents such as clay and talc, other fillers, pigments,
Antioxidants, stabilizers, processing aids, internal mold release agents, and the like may be added and blended. In producing the composition of the present invention, it is desirable that the components (A), (B), (C), (D) and, if necessary, other additives are sufficiently mixed.

This mixing is carried out by using a kneading roll, a kneader, a Banbury mixer, an extruder, etc., which are conventionally used. The working conditions at the time of mixing are not particularly limited, but usually the additive compound can be dispersed in the copolymer by kneading at about 30 to 100 ° C. at a temperature at which vulcanization hardly occurs, for about 1 to 60 minutes. Further, these additive compounds can be appropriately dispersed in a solvent and mixed as a suspension solution.

Further, so-called wet mixing in which the mixing is performed in the medium from the beginning can also be performed. In this case, a solution or dispersion liquid composition can be obtained by using a mixer such as a roll, a ball mill, and a homogenizer. It is desirable that the operating conditions at the time of mixing be determined by selecting optimal conditions according to the types and purposes of the raw materials and the compounding agents used.

The composition of the present invention can be formed into a sheet, a pipe, a rod, a tube, an angle by continuous molding methods such as extrusion molding, transfer molding, roll coating, brushing and impregnation in addition to mold molding and injection molding. , Channel, tabi,
It can be formed into a molded product such as a coated plate. Further, it can be formed into a deformed product or a specially formed product, for example, a sponge-like rubber, by various other forming methods. The composition thus formed is vulcanized by the following vulcanizing means to obtain a vulcanized rubber product.

In the present invention, the vulcanization operation may employ an operation conventionally used conventionally. For example, an operation of heating while applying pressure in a molding die may be employed, or an operation of heating in a heating furnace or the like after molding by extrusion molding or injection molding may be employed. The vulcanization temperature is usually 100
To 400 ° C., preferably about 150 to 200 ° C., and the vulcanization time ranges from about 30 seconds to several hours. The obtained vulcanized product may be subjected to secondary vulcanization. Physical properties may be improved by secondary vulcanization. The secondary vulcanization conditions are not particularly limited, and are appropriately selected depending on the shape and size of the molded product.
At 150-250 ° C, preferably 180-230 ° C, 2
It is about 25 hours.

[0027]

The TFE-P having a small number of polymerized units based on VdF is used.
In the -VdF copolymer, the organic peroxide vulcanization proceeds easily by introducing a carbon-carbon unsaturated bond into the copolymer molecule. Also, the vulcanizing composition exhibits excellent scorch stability.

[0028]

EXAMPLES Examples 1 to 6 are Examples and Examples 7 to 10 are Comparative Examples. Materials mixed with the compositions (units: parts by weight) shown in Tables 1 and 2 were uniformly mixed with two rolls to obtain a copolymer composition.
The vulcanization characteristics of this composition were measured using an oscillating disc rheometer (manufactured by Toyo Seiki).
The minimum torque (M _L ), maximum torque (M _H ), and time to reach 90% of the maximum torque value (t _c (90)) were measured at 24 ° C. for 24 minutes. The Mooney scorch test of this composition was performed according to JIS-K-6300.
According to Mooney scorch time t ₅ (minutes), and t ₃₅
(Min) was measured. This composition was press-vulcanized at 170 ° C. for 20 minutes and then heat-treated in an oven at 230 ° C. for 24 hours to perform secondary vulcanization.

The obtained vulcanized product was measured for physical properties in normal conditions, heat resistance (70 hours at 230 ° C.), and oil resistance (70 hours at 175 ° C.) in accordance with JIS-K-6301. For the measurement of oil resistance, an SH class engine oil (Castle Motor Oil Clean SH manufactured by Toyota Motor Corporation) was used. Table 3 shows the results.
It is shown in Table 4.

Table 5 shows the abbreviations of Tables 1 and 2. The respective copolymers used were produced by emulsion polymerization. Table 5 also shows the content ratio (mol%) of the polymerized units based on the respective monomers and Mooney viscosity ML _{1 + 10} (121 ° C.). . The composition of the polymerized unit based on each monomer of the component (A) is as follows:
^{It was determined by 19} F-NMR and ¹ H-NMR. Also,
The unsaturated bond in the copolymer has a wave number of 1722 in infrared analysis.
The presence was confirmed by the absorption at cm ^-1 (hereinafter simply referred to as absorbance).

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

[0036]

EFFECTS OF THE INVENTION TFE having a carbon-carbon unsaturated bond in the copolymer molecule and a small content of polymerized units based on VdF,
The composition containing the -P-VdF-based copolymer exhibits good organic peroxide vulcanizability and scorch stability, heat resistance,
Gives vulcanizates with excellent oil resistance. Furthermore, the vulcanized product has various excellent vulcanized physical properties, such as radiators of automobiles, O-rings around engines, gaskets, sealing materials, diaphragms, tubes, hoses, and similar parts such as food plants and chemical plants. It is very useful for a wide range of applications such as

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/49 C08K 5/49 C08L 23/14 C08L 23/14 // C08F 8/00 C08F 8/00 214 / 26 214/26 (C08F 214/26 210: 06 214: 22) F-term (reference) 4J002 BB141 BD141 BD151 DE078 DE088 DE108 DE158 EK007 EK037 EK047 EN136 EV296 EW176 FD147 FD156 FD208 GJ02 GN00 4J100 AA03Q AC24R AC26P CA05 CA30 DA30 HB39 HB44 HB52 HC09 HC12 HC27 HC28 HC43

Claims (1)

[Claims] (A) 35-65 mol% of a polymerization unit based on tetrafluoroethylene, 20-50 mol% of a polymerization unit based on propylene, and 0.5-15 mol% of a polymerization unit based on vinylidene fluoride. A copolymer having a carbon-carbon unsaturated bond in the copolymer molecule,
A copolymer composition comprising (B) an organic onium compound, (C) an organic peroxide, and (D) at least one selected from metal oxides and metal hydroxides.