JPH02196818A - Rubber-like copolymer, production thereof and vulcanizable rubber composition - Google Patents

Abstract

PURPOSE:To obtain the title new copolymer providing vulcanized materials having excellent oil resistance, freeze resistance, heat resistance, etc., by copolymerizing a dicyano-vinylcyclopropane with a difluoro-vinylcylcopropane in the presence of a free radical initiator. CONSTITUTION:(A) A 1,1-dicyano-2-vinylcyclopropane is copolymerized with (B) a 1,1-difluoro-2-vinylcylcopropane in the presence of a free radical initiator (e.g. t-butylhydroperoxide) preferably by bulk polymerization to give the aimed copolymer which is a linear polymer having a molecular structure shown by formula I and/or formula II (R is H, CH3 or Cl; X is CN or F), comprises 5-95wt.% unit based on the component A and 95-5wt.% unit based on the component B and has 2,000-2,000,000 weight-average molecular weight calculated as standard polystyrene. The polymerization temperature is preferably 0-100 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention comprises: 1.・New rubbery copolymers having structural units based on 1-dicyano-2-vinylcyclopropanes and 1,1-difluoro-2-vinylcyclopropanes, hydrogenated polymers thereof, and copolymers of the copolymers. Regarding the production method and the vulcanizable rubber composition based on the copolymer, the composition has improved oil resistance, cold resistance, heat resistance, sour gasoline resistance, alcohol mixed gasoline resistance, and alcohol mixed sour gasoline resistance. This gives a vulcanized product.

(Prior art) 1.1-dicyano-2- and nylcyclopropanes and 1,
It is already known that linear polymers can be obtained individually from 1-difluoro-2-vinylcyclopropanes. Radical ring-opening polymerization of -2-vinylcyclopropane (J, Polym, Sci
,, Polymer Chew, Ed, + Earthwork.

3169, (1979)L Recently, ring-opening polymerization of 1,1-dicyano-2-vinylcyclopropane using palladium (Polyn+er Preprint, Japan
n, 37 people υ-, 259. (198B)), also 2,
1 using 2-azobisisobutyronitrile as an initiator,
Radical ring-opening polymerization of 1-difluoro-2-vinylcyclopropane (Polymer Set, tlssR, l
3 (9), 2421° (1971)). It has been shown that the homopolymers obtained by these methods are all linear polymers having unsaturated bonds in their main chains. However, the homopolymer obtained from 1,1-dicyano-2-vinylcyclopropane has poor flexibility and its film is too brittle to be used as a rubber material. Copolymerization with vinyl compounds such as styrene, acrylonitrile, or vinyl acetate is also possible;
The copolymer obtained has a low molecular weight, and the homopolymer obtained from 1,1-difluoro-2-vinylcyclopropane has crystallinity and cannot be described as rubbery, and has a low molecular weight.

On the other hand, conventionally, acrylonitrile-butadiene copolymer rubber ( (hereinafter referred to as NBR) or highly saturated rubber containing a nitrile group (hereinafter referred to as H3N), etc. are used.

However, in recent years, as part of the global effort to develop alternative energy to petroleum, many countries have been considering using alcohols such as ethanol and methanol mixed with gasoline, and this has already reached the stage of practical application. However, when such alcohol-mixed gasoline is used as an automobile fuel, it has a large effect on rubber materials, and the oil-resistant rubber that has been commonly used in the past increases swelling, making it difficult to use it as automobile parts. The effect is especially severe on methanol-mixed gasoline, and the swelling increases significantly, so conventional oil-resistant rubbers can no longer be used for performance and safety reasons.

On the other hand, in recent years, due to measures taken against automobile exhaust gas, the atmosphere around the engine tends to be hotter than before, and gasoline is easily oxidized and becomes rancid gasoline (hereinafter referred to as sour gasoline), which circulates. Therefore, conventional oil-resistant rubber can no longer be used. It is known that such rancidity occurs similarly with alcohol-mixed gasoline, and therefore rubber materials that are used in contact with alcohol-mixed gasoline must have oil resistance against alcohol-mixed gasoline as well as resistance to sour gasoline. There is a strong desire for an oil-resistant rubber that has significantly improved performance compared to conventional oil-resistant rubber.

Among conventional oil-resistant rubbers, fluororubber is known as a rubber that exhibits relatively superior performance in terms of the above characteristics.
This rubber has the drawback of extremely poor cold resistance and cannot be used in cold regions. To improve this cold resistance, a low-temperature plasticizer may be used in combination, but in this case, the plasticizer will be extracted into the gasoline during practical use, and no improvement effect will be shown over a long period of time.

(Problem to be Solved by the Invention) Therefore, the object of the present invention is to develop a new method having structural units based on 1,1-dicyano-2-vinylcyclopropanes and 1,1-difluoro-0-2-vinylcyclopropanes. A rubbery copolymer, a hydrogenated polymer obtained by hydrogenating an olefinically unsaturated group contained in the copolymer, a method for producing the copolymer, and oil resistance based on the copolymer, The object of the present invention is to provide a vulcanizable rubber composition that provides a vulcanizate with improved cold resistance, heat resistance, sour gasoline resistance, alcohol mixed gasoline resistance, and alcohol mixed sour gasoline resistance.

(Means for Solving the Problems) The objects of the present invention are as follows (1), (2), (3), or (4).
) is achieved.

(1) Below! and/or a linear polymer having a molecular structure of (A) 1,1-dicyano-2
- 5 to 95% by weight of structural units based on vinylcyclopropanes and (B) 95 to 5% by weight of structural units based on 1,1-difluoro-2-vinylcyclopropanes, weight calculated on standard polystyrene. Average molecular weight is 200
A rubbery copolymer having a molecular weight of 0 to 2 million.

CH! CH=CCCHHz (n)R
=H, CH2 or CH2°X=CN or F (2) A hydrogenated polymer obtained by hydrogenating the olefinically unsaturated group contained in the rubbery copolymer described in (1) above.

(3) The above method (which is characterized by copolymerizing 1,1-dicyano-2- and nylcyclopropanes and 1,1-difluoro-2- and p-lycyclopropanes in the presence of a free radical initiator) 1) Method for producing the rubbery copolymer described above.

(4) The rubber described in (1) above or the hydrogenated polymer described in (2) above, and a sulfur-based vulcanizing agent, a peroxide vulcanizing agent, a polyamine-based vulcanizing agent, or a polyhydroxyaromatic vulcanizing agent A vulcanizable rubber composition comprising:

The rubbery copolymer of the present invention comprises 1,1-dicyano-2-vinylcyclopropanes and 1,1-difluoro-2
- produced by copolymerizing vinylcyclopropanes in the presence of free radical initiators.

Free radical initiators that can be used include:
Examples include free radical initiators that are usually used in radical polymerization of vinyl compounds, and there are no particular limitations. For example, t-
Butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, 2,5-dimethylhexane-2,5-hydroperoxide, 1.1.3.
3-tetramethylbutyl hydroperoxide, di-t-
Butyl peroxide, di-butyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5
-di<1-butylperoxy)hexane, 2,5-dimethyl-2,5-di(1-butylperoxy)hexane-3, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, Benzoyl peroxide, m-toluoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, mu-butyl peroxyacetate, preferably 2,5-dimethyl-2,5-di(neodecanoylperoxy)hexane , 2,5-dimethyl-2
, 5-di(2-ethylhexanoylperoxy)hexane; inorganic peroxides and persulfates such as hydrogen peroxide, potassium persulfate, ammonium persulfate; or known redox initiators. system, or
For example, 2.2-azobis(2-methylbutyronitrile)
, 1.1-azobis(1-cyclohexanebutyronitrile), 2-(carbamoylazo)-isobutyronitrile,
2.2-azobis(2,4,4-)lyntylbentane)
, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2-azobis(2-methylpropane), preferably 2,2-azobis(2,4-dimethylvaleronitrile L2,2-azobis Examples include azobis-based initiators such as isobutyronitrile and 2,2-azobis-(4-methoxy=2,4-dimethylvaleronitrile).

The polymerization reaction is preferably carried out by bulk polymerization, but if necessary, emulsion polymerization, suspension polymerization, hydrocarbons such as benzene and toluene, and halogenated hydrocarbons such as chlorobenzene and methylene chloride may be used. Alternatively, a solution polymerization method using an ether such as ethyl ether as a diluent can also be used. The temperature of the polymerization reaction is approximately -20°
The temperature can be varied from C to 200°C, preferably from 0 to 100°C, and atmospheric pressure is usually used, but it can also be varied from reduced pressure to several tens of atmospheres.

The rubbery copolymers thus obtained were all 1
．． 1-dicyano-2-vinylcyclopropanes and 1,1
As with homopolymers obtained by polymerizing vinylcyclopropane derivatives, such as -difluoro-2-vinylcyclopropanes, respectively in the presence of a free radical initiator, the structure is as claimed in claim (1). It is a linear copolymer in which the described structure (1) or (2) or both (1) and (H) are present and has an unsaturated bond in the main chain. Furthermore, the composition of the rubbery copolymer is (A) 1,1-dicyano-2
- 5 to 95% by weight of structural units based on vinylcyclopropanes and (B) 95 to 5% by weight of structural units based on 1,1-difluoro-2-vinylcyclopropanes, preferably 10 to 70% by weight of the former; %, the latter being 90-30% by weight
It is. When (A) exceeds 95% by weight, it is difficult to obtain a rubber-like copolymer with high flexibility, and when (B) exceeds 95% by weight, the copolymer has crystallinity. Put it away,
The copolymer has a weight average molecular weight of 2,000 to 2,000,000 in terms of standard polystyrene, preferably 50,000 to 10,000.
If the zero weight average molecular weight is less than 2,000, it is undesirable because it causes a decrease in strength in the properties of the vulcanizate, and when it exceeds 2,000,000, it is unfavorable because processability deteriorates.

The hydrogenation reaction of the olefinically unsaturated groups contained in the rubbery copolymer can be carried out by a conventional method.

As for the catalyst used, as a homogeneous catalyst, Wilkinson type catalyst, RhCIl (PPhs) 2
RuH(Cl)(PPhs)s, cobalt acetate/triethylaluminum, nickel acetylacetonate/triisobutylaluminum, etc.
For heterogeneous catalysts, Pd-activated carbon, Ru-activated carbon, Ni
- Group Ⅰ metals supported on carriers such as activated carbon, silica, diatomaceous earth, and alumina, such as diatomaceous materials, are used.

The hydrogenation reaction varies depending on the catalyst, but at normal pressure to 200kg/
It is carried out under a hydrogen pressure of C1i at a temperature of 0 to 200°C. The hydrogenation rate is 1% to 90%, preferably 20%.
% or more and within 60%. If the hydrogenation rate is the above value,
The heat resistance and methanol sour gasoline resistance of the obtained hydrogenated polymer are further improved.

It is confirmed using infrared spectroscopy and nuclear magnetic resonance spectroscopy that the copolymer is a linear polymer having a molecular structure of specific structure (1) and/or II. Glass transition temperature is measured using a differential scanning calorimeter. Furthermore, the bond content of each monomer component is calculated from the nitrogen content analysis value by the Kjeldal method or the fluorine content analysis value by the combustion flask method.The weight average molecular weight is determined by GPC (gel permeate chromatography). do.

The sulfur-based vulcanizing agent used in the present invention may be any commonly used sulfur or sulfur donor, specifically thiuram-based compounds such as morpholine disulfide and tetramethylthiuram disulfide; Examples include polymer polysulfides.

Further, as the peroxide vulcanizing agent, commonly used organic peroxides can be used, and there are no particular limitations. For example, dicumyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, cumene hydroperoxide, cumene hydroperoxide, benzoyl peroxide, 2.
4-dichlorodibenzoyl peroxide, 2,5-dimethyl-2,5-di(L-butylperoxy)hexane,
2.5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,1,1-di(t-butylperoxy)-3,3,5-)limethylcyclohexane, t-butylperoxybenzoate, 2,5-dimethyl-2,5
-di(benzoylperoxy)hexane, 1,3-di(
Examples include t-butylperoxyisopropyl)benzene.

Examples of the polyamine vulcanizing agent include hexamethylene diamine carbamate, N,N-dicinnamylidene-1,6-hexane diamine, and the like.

Examples of polyhydroxy aromatic vulcanizing agents include 2,2-his(4-)-droxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)perfluoropropane, and quaternary phosphonium Salts or quaternary ammonium salts are used in combination.

Note that a peroxide-based vulcanizing agent and triallylisocyanurate, trimethylolpropane triacrylate, or the like may be used in combination.

The amount of these sulfur-based vulcanizing agents, peroxide vulcanizing agents, polyamine-based vulcanizing agents, and polyhydroxyaromatic vulcanizing agents is not particularly limited in the present invention, but usually the rubber-like copolymer The amount ranges from 0.5 to 10 parts by weight per 100 parts by weight of the combination.

Furthermore, ordinary rubber compounding agents such as fillers, reinforcing agents, plasticizers, processing aids, and anti-aging agents can be optionally blended into the rubbery copolymer or hydrogenated polymer thereof in the present invention.

Mixing rolls, which have traditionally been used in the rubber processing field, are used to blend various additives into rubber.
Any means such as Banbury mixer 1, various types of Nigoo I, etc. can be used. The obtained rubber composition usually has 10
It can be made into a vulcanizate by heating to 0 to 200°C. Vulcanization time varies depending on temperature, but is 1 to 120
It is usually done within minutes. As the vulcanization molding method, usual rubber vulcanization molding methods such as pressure vulcanization using a mold, injection molding, heating with a steam oven or microwave can be used.

(Effects of the Invention) The rubbery copolymer or hydrogenated polymer of the present invention has a high molecular weight, and the rubber vulcanizate obtained using the same can be used for automobile fuel hoses, seals, gaskets, O-rings, and diaphragms. , or as belts, boots, or rolls, etc. Oil resistant, cold resistant, heat resistant, sour gasoline resistant,
It shows an excellent balance of performance in terms of resistance to alcohol mixed gasoline and alcohol mixed sour gasoline.

The present invention will be explained in more detail with reference to Examples below. Note that parts and percentages in Examples, Comparative Examples, and Reference Examples are based on weight unless otherwise specified.

Reference example 1 25% of 1,3-butadiene was placed in a glass container with a content of 31%.
500 sffi of QgSn-hexane was charged, and while stirring vigorously, 500 g of bromine was added dropwise over 6 hours at -15 to -25°C to react.
310g of was obtained. Furthermore, the content is 3J! In a glass container, 8001 L of tetrahydrofuran, 92 g of malononitrile, 325 g of im oxide and the above 1,4-dibromobutene-
Prepare 300g of 2 and read the literature (Journal of t
he American Chemical Society
ty, 88 (9), 1979, (1
966)),
51 g of 1.1-dicyano-2-vinylcyclopropane was obtained.

Reference Example 2 Epichlorohydrin 22 was added to a 31 stainless steel reactor.
50 g, 1,3-butadiene 120 g, monochlorodifluoromethane 530 g, including 42 stories of tetrabutylammonium chloride, literature (Chemische B
Erichte, l O9(7), 2351.

(1976)), 1. l-difluoro-2-vinylcyclopropane 70
I got g.

Example 1 The inside of a glass polymerization reactor with an internal capacity of 100 mf was replaced with nitrogen, and the amounts of 1,1-dicyano-2-vinylcyclopropane, 1,1-difluoro-2-, and nylcyclopropane shown in Table 1 were added. and 2.2-azobis(2,4-dimethylvaleronitrile) and polymerized at 40°C for 19 hours. After polymerization, coagulate with a large amount of methanol, and
Dry under reduced pressure for 4 hours to obtain a rubbery copolymer (experiment numbers 1 to 4)
and 1,1-dicyano-2-vinylcyclopropane homopolymer (experiment number 6) and 1,1-difluoro-2-
A vinylcyclopropane homopolymer (experiment number 5) was obtained.

Each of the obtained copolymers 1 to 4 was rubber-like,
The presence of a single glass transition point was observed by differential scanning calorimetry. When measured by infrared spectroscopy, it was observed that the above copolymers all produced an absorption (970C!l-') attributed to the trans double bond, and an absorption (910,990CII) attributed to the terminal vinyl group. It was confirmed that the bow) had disappeared. For reference, the results of infrared spectroscopy measurements conducted on the copolymer of Experiment No. 3 are shown in Figure 1. Also, in the measurements by nuclear magnetic resonance spectroscopy,
Two absorptions are observed due to chemical shift of hydrogen bonded to unsaturated carbon and saturated carbon, and the area ratio is l:
It was 2.

From the above, each obtained copolymer is claimed in the patent claim (
1) The yield, weight average molecular weight and composition of the polymer confirmed to have the structure I or II described above are shown in Table 1. The i weight average molecular weight is 1.1-dicyano-2 - Each polymer except vinylcyclopropane homopolymer was measured by GPC (gel permeation chromatography). Also 1,1-dicyano-2
- for vinylcyclopropane homopolymers, N, N
- The intrinsic viscosity at 30°C was determined by dissolving in dimethylformamide. The composition of the copolymer was determined from the fluorine content analysis using the combustion flask method.

Example 2 The inside of a glass polymerization reactor with an internal capacity of 100 mff1 was replaced with nitrogen, and 1,1-dicyano-2-vinylcyclopropane, 1,1-difluoro-2-vinylcyclopropane,
and an initiator, and polymerized for 19 hours under the conditions shown in Table 2. After polymerization, coagulate with a large amount of methanol and hold at 60°C.
After drying under reduced pressure for 24 hours, the rubbery copolymer (experiment number 7~
9) and a 1,1-difluoro-2-vinylcyclopropane homopolymer (Experiment No. 10) were obtained. Each of the obtained copolymers 7 to 9 was rubber-like and had the same molecular structure as the copolymer obtained in Example 1.

Example 3 The inside of a glass polymerization reactor with an internal capacity of 60011ffi was replaced with nitrogen, and the amounts of 1,1-dicyano-2-vinylcyclopropane, l,1-difluoro-2-vinylcyclopropane, and 2.2-azobis(2,4-dimethylvaleronitrile) was charged and polymerized at 40°C for 24 hours. After the polymerization was completed, it was coagulated with a large amount of methanol and
A copolymer was obtained by drying under reduced pressure at °C for 24 hours. Each of the obtained copolymers was rubber-like and had a molecular structure similar to that of the copolymer obtained in Example 1.

Example 4 The inside of a glass polymerization reactor with an internal capacity of 600 mf was replaced with nitrogen, and the amounts of 1,1-dicyano-2-vinylcyclopropane, 1,1-difluoro-2-vinylcyclopropane, and 2.2-azobisisobutylnitrile was charged and polymerized at 65°C for 17 hours. After completion of polymerization, the mixture was coagulated with a large amount of methanol and dried under reduced pressure at 60°C for 24 hours to obtain a copolymer. The obtained copolymer was rubbery and had a molecular structure similar to that of the copolymer obtained in Example 1.

After completion of the hydrogenation reaction in which the hydrogenation reaction was carried out at 100'C for 2 hours, a hydrogenated polymer was obtained. The measurement results of this hydrogenated polymer by infrared spectroscopy are shown in Figure 2. The hydrogenation rate was measured using NMR.

Table 5 Example 5 Example 3 was placed in a stainless steel autoclave with an internal capacity of 11.
1,1-dicyano-2-vinylcyclopropane (47% by weight)-1,1-difluoro- obtained in the same manner as
Copolymer rubber of 2-vinylcyclopropane (53% by weight), tetrahydrofuran and Wilkinson complex Ph
Prepare CII CPPhs)s in the amount shown in Table 5.
Hydrogen pressure 100 kg/cd, Example 6 1,1-dicyano-2 obtained in the same manner as Example 3
-Vinylcyclopropane (47% by weight) -1,1-difluoro-2-vinylcyclopropane (53% by weight) copolymer rubber and the hydrogenated polymer obtained in Example 5 were blended as shown in Table 6. According to the recipe, the mixture was mixed with other ingredients on a roll at 20°C and heated at 160°C for 30 minutes to prepare a vulcanizate. Next, the characteristics of the vulcanizate were determined according to JISK ~ 6301.
It was measured by

The results are shown in Table 6. Both vulcanization systems have good vulcanization physical properties.

Table ** Vulcanization-accelerated rhinoceros manufactured by Montefloss Example 7 1,1-dicyano-2 obtained by the same method as Example 3
- copolymer rubber of vinylcyclopropane (49% by weight)-1,1-difluoro-2-vinylcyclopropane (51% by weight) and the hydrogenated polymer obtained in Example 5, and NB
An experiment similar to that in Example 6 was conducted using R and MSN according to the formulation shown in Table 6. The results are shown in Table 7.

In the air heating aging test, experiment number 20 broke, and
In the methanol sour gasoline immersion test, test No. 20 broke and test No. 21 softened.

harm table (M)

[Brief explanation of the drawing]

FIG. 1 is a chart of the rubbery copolymer obtained in Experiment No. 3 of Example 1 measured by infrared spectroscopy. An absorption attributable to the trans double bond is observed at 970C111-' and an absorption attributable to -CN at 2250 cm-'. In addition, the absorption attributed to the terminal vinyl group (910C1
-', 990C1-') have all disappeared. FIG. 2 is a chart of the hydrogenated polymer obtained in Example 5 measured by infrared spectroscopy. From a comparison with Figure 1, it is clear that the absorption attributed to the trans double bond of 970CI+-' has decreased, indicating that the hydrogenation reaction is proceeding. Nippon Zeon Co., Ltd. 2,5-dimethyl-2,5-di(tertbutylperoxy)hexane Patent Applicant Nippon Zeon Co., Ltd.

Claims (4)

[Claims] (1) A linear polymer having the following molecular structure I and/or II, wherein (A) 5 to 95% by weight of structural units based on 1,1-dicyano-2-vinylcyclopropanes.
and (B) consists of 95 to 5% by weight of structural units based on 1,1-difluoro-2-vinylcyclopropanes, and has a weight average molecular weight of 2000 to 2000 in terms of standard polystyrene.
A rubbery copolymer characterized in that it has a molecular weight of 2,000,000. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II R=H, CH_3 or ClX=CN or F (2) A hydrogenated polymer obtained by hydrogenating the olefinically unsaturated group contained in the rubbery copolymer according to claim (1). (3) Claim (1) characterized in that 1,1-dicyano-2-vinylcyclopropanes and 1,1-difluoro-2-vinylcyclopropanes are copolymerized in the presence of a free radical initiator. A method for producing the rubbery copolymer described. (4) The rubbery copolymer according to claim (1) or the hydrogenated polymer according to claim (2) and a sulfur-based vulcanizing agent, a peroxide vulcanizing agent, a polyamine-based vulcanizing agent, or a polyhydroxy aromatic A vulcanizable rubber composition characterized by containing a group-based vulcanizing agent.