JP2653658B2 - Modified low molecular weight conjugated diene polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a modification in which a cyclopropane ring having a halogen atom or an alkoxycarbonyl group is introduced into a molecular chain, which is preferably used as a sealing material, a coating material, or the like. The present invention relates to a low molecular weight conjugated diene polymer.

[Conventional technology]

Conjugated diene-based polymers or copolymers such as low molecular weight polybutadiene and polyisoprene exhibit sufficient fluidity at room temperature or slight heating, and their cross-linked products have excellent zome elasticity, sufficient mechanical strength, and practical use. The crosslinked product is widely used as a sealing material, a coating material, an adhesive, a pressure-sensitive adhesive, or a molded product because it has durability without problems. However, ordinary conjugated diene-based polymers do not always have sufficient adhesiveness to polar substances such as metals and fiber materials, and for the purpose of improving adhesiveness, adhesive aids such as tackifier resins, isocyanate compounds, and metal compounds are used. Addition is performed. However, the method using an additive may have a problem in solubility and dispersibility of the additive in a low molecular weight conjugated diene polymer, and may cause a problem such as deterioration in performance due to deterioration attributed to the additive. However, it is not always enough. As another method, an attempt has been made to improve the adhesiveness by introducing a polar group into a low molecular weight conjugated diene-based polymer and increasing the affinity with materials such as metals and fibers. Usually, carbonyl groups and halogen atoms are relatively widely used as polar groups that contribute to adhesiveness. Examples of the method of introducing a carbonyl group include a method of copolymerizing a monomer having a carbonyl group and a conjugated diene monomer, and a method of adding a compound having a carbonyl group to a conjugated diene-based polymer. That is, as the former copolymerization method, a method of copolymerizing 1,3-butadiene and methyl methacrylate [C. Walling and JADauison, JA
m.Chem.Soc. 73 , 5736 (1951)], a method of copolymerizing isoprene and methyl methacrylate [E. Oikawa and K. Yam
amoto, Polymer J. 1 , 669 (1970)], 2-chloro-1,3-
Method for copolymerizing butadiene and vinyl acetate [SNUs
hakov and LB Trukhmanova, CA 52 , 42371 (1958)] and the like, and the latter addition method is a method of adding acetic acid to polyethylene containing a carbon-carbon double bond in the presence of di-t-butyl peroxide [Belgian Patent No. 659020 (1965)], a method of adding maleic anhydride to synthetic rubber (Japanese Patent Publication No. 47-
15702 gazette) etc. Of these, the former method of copolymerization has problems in reactivity at the time of copolymerization, and it is difficult to control the composition ratio, it is difficult to increase the polymerization rate, and it is difficult to control the molecular weight. There is. Further, as a method of adding a compound having a carbonyl group to a polymer, a method of adding maleic anhydride is well known and widely studied, but with this method, gelation during the reaction or remarkable increase in viscosity is caused. Then
In addition, coloring of the polymer may occur, which is not always a good method. In addition, other reactions using thioglycolic acid, nitrosamine, etc. are also known, but they have drawbacks such as a low reaction rate, a large odor of the product, and a large coloring.

As a method of introducing a halogen, a method of reacting a conjugated diene polymer with hydrogen halide or a halogen molecule is used as a method of introducing a halogen atom. There is a problem that molecules and hydrogen halide are eliminated, and it is necessary to introduce a certain amount of halogen atoms in order to suppress this problem as much as possible, and it is impossible to control the amount of halogen atoms introduced over a wide range. It is the actual situation.

[Problems to be solved by the invention]

An object of the present invention is to obtain a modified low-molecular weight conjugated diene-based copolymer which has a halogen atom, a carbonyl group, etc. introduced in a stable manner and can be preferably used as a material such as a sealing material and a coating material in a stable manner. It is in.

[Means for solving the problem]

According to the present invention, the above object is achieved by a modified low molecular weight conjugated diene-based polymer having a cyclopropane ring having a halogen atom or an alkoxycarbonyl group introduced into a molecular chain. That is, the present invention is selected from the group consisting of polyisoprene, a copolymer of two or more conjugated dienes, and a copolymer of a conjugated diene and another vinyl compound, having a molecular weight of 10,000 to 100,000 and 1,4-bond Ethylenic double bond of low molecular weight conjugated diene polymer with content of 70 mol% or more (
A cyclopropane ring structure to which a halogen atom or an alkoxycarbonyl group is added, in which a part of C = C) is represented by the following formula (Wherein, _one of Y ₁ and Y ₂ is a halogen atom and the other is a halogen atom or a hydrogen atom, or one is an alkoxycarbonyl group and the other is an alkoxycarbonyl group or a hydrogen atom) The present invention relates to a low molecular weight conjugated diene polymer.

In the above, the halogen atom includes a chlorine atom, an odor atom and the like, and the alkoxycarbonyl group includes an alkoxycarbonyl group having 1 to 12 carbon atoms.

The low molecular weight conjugated diene-based polymer used in the present invention is a homopolymer of isoprene, a copolymer of two or more conjugated dienes, a copolymer of a conjugated diene such as isoprene and butadiene and a copolymer of other vinyl compounds. It is a polymer selected from the group consisting of:

It is important that these low molecular weight conjugated diene-based polymers show fluidity at room temperature to slight heating, and therefore the molecular weight thereof needs to be in the range of 10,000 to 100,000. If the molecular weight is smaller than the above range, the crosslinked product obtained from the low molecular weight conjugated diene polymer will have poor mechanical properties, and the crosslinking reaction will be insufficient. On the other hand, when the content exceeds the above range, the fluidity is insufficient or insufficient, and it cannot be used for a sealing material, a coating material and the like. Such a conjugated diene-based polymer is generally known, a method of obtaining a polymer by radical polymerization of a conjugated diene monomer using a radical catalyst such as a peroxide or an azo compound, sodium, an alkali metal such as lithium or the like. It is obtained by a method of anionic polymerization using an anion catalyst such as an organic compound. Of these, it is easy to control the molecular weight of the low molecular weight conjugated diene polymer produced by the anionic polymerization method,
Further, the polymerization reaction can be controlled relatively easily, which is preferable. More specifically, butyllithium, ethyllithium, low molecular weight polyisoprene obtained by polymerizing isoprene with a lithium-based catalyst such as naphthyllithium, or polyisoprene-polybutadiene block obtained by sequentially polymerizing isoprene and butadiene. Copolymer, further obtained by sequentially polymerizing conjugated diene and styrene which is a vinyl-based monomer, polybutadiene-polystyrene block copolymer,
A polyisoprene-polystyrene block copolymer is preferably used.

When the conjugated diene-based polymer is a copolymer, it may have various forms such as random form and block form.
Here, when the conjugated diene-based polymer is a block copolymer, specific examples thereof include, for example, the following formula (AB) n (AB) nAB- (AB) n (formula Among them, A and B are those represented by A is polyisoprene and B is polybutadiene, or A is polybutadiene or polyisoprene and B is polystyrene, and n is an integer such as 1, 2). .

A cyclopropane ring is introduced into the conjugated diene polymer, which can be easily carried out by mixing the conjugated diene polymer and the carbene generator in a basic atmosphere. The carbene generator polyhalogenated methane, N ₂ CR ₁ R ₂ (alkoxycarbonyl Cal carbonyl group of R ₁ = H or C ₁ -C _12, alkoxycarbonyl group of R ₂ = C ₁ ~C ₁₂₎
A diazo compound represented by or HXCR ₃ R ₄ , X ₂ CR ₃ R ₄ (R ₃ =
H or C ₁ -C ₁₂ alkoxycarbonyl group, R ₂ = C ₁ -C ₁₂
[Alpha] -haloester compound represented by the alkoxycarbonyl group of X and a halogen atom) is preferably used.

Examples of halogenated methane include dibromomethane, tribromomethane, carbon tetrabromide, dibromomethane, trichloromethane, carbon tetrachloride and the like.Examples of the diazo compound include methyl diazoacetate and ethyl diazoacetate,
Examples thereof include dimethyl diazomalonate and diethyl diazomalonate.

As α-haloester, methyl chloroacetate,
Examples include ethyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, methyl dichloroacetate, ethyl dichloroacetate, methyl dibromoacetate, ethyl dibromoacetate, dimethyl chloromalonate, diethyl chloromalonate, dimethyl bromomalonate and diethyl bromomalonate. By using a halogenated methane as a carbene generator, it is possible to introduce a cyclopropane ring having a halogen,
By using the above diazo compound or α-haloester, it becomes possible to introduce a cyclopropane ring having an alkoxycarbonyl group.

Introduction reaction of cyclopropane ring is pentane, hexane,
It is carried out by mixing the conjugated diene polymer and the carbene generator in an aliphatic solvent such as heptane, an alicyclic solvent such as cyclohexane and methylcyclohexane, or an aromatic solvent such as benzene, toluene and xylene. At this time, a basic compound is used as a catalyst, and examples thereof include hydroxides of alkali metals such as NaOH and KOH, alkoxides such as sodium methoxide and potassium tert-butoxide, and alkyl compounds such as BuLi. Of these, hydroxides such as NaOH and KOH are used in the form of an aqueous solution. In this case, a quaternary ammonium salt such as triethylpentylammonium chloride is preferably used as a co-catalyst in order to make the reaction proceed smoothly. Among the above-mentioned basic compounds, it is preferable to use hydroxides such as NaOH and KOH because of the uniformity of reaction and the ease of control.

The amount of the catalyst used is 0.1 in molar ratio with respect to the halogenated methane, diazo compound or α-haloester compound used.
Used in the range of up to 100. When a cocatalyst is used, it is used in a molar ratio of 0.001 to 0.1 with respect to the amount of the catalyst used. The amount of the cyclopropane ring structure to be introduced is preferably in the range of 0.05 to 50 mol% based on the diene units (that is, the ethylenic double bond units) of the conjugated diene polymer. If the introduction amount of the cyclopropane ring structure is less than the above range, the effect of improving the adhesiveness cannot be obtained. On the other hand, if the amount exceeds the above range, the reaction itself becomes difficult, and gelation, thickening or remarkable deterioration is caused during the reaction, which is not preferable. From such a viewpoint, the introduction amount of the cyclopropane ring structure is more preferably in the range of 0.5 to 30 mol% with respect to the diene unit. The cyclopropane ring structure is usually introduced at a reaction temperature of 0 to 250 ° C. The reaction time at this time may vary depending on the reaction temperature, but is generally 0.
It ranges from 1 to 50 hours. After the reaction is completed, the basic compound used as a catalyst is removed by washing with water or the like, and the solvent is removed by drying under reduced pressure. Alternatively, the reaction mixture is poured into a non-solvent such as methanol to precipitate a polymer, and the polymer is dried. The target modified low molecular weight conjugated diene polymer is obtained by

The modified low molecular weight conjugated diene-based polymer of the present invention utilizes a halogen atom additionally introduced and an alkoxycarbonyl group,
Used by cross-linking. Examples of the crosslinking agent used here include metal oxides such as zinc oxide and magnesium oxide; metal hydroxides such as calcium hydroxide and magnesium hydroxide; metal salts such as zinc acetate and calcium acetate; and ethylene oxide such as ethylenediamine and diethylenetriamine. A valent amine or the like is used. At the time of crosslinking, 0.01 to 50 parts by weight of the above crosslinking agent is added to 100 parts by weight of the polymer, and the solvent is used at room temperature to 25.
The reaction may be performed at about 0 ° C for 0.1 to 48 hours.

Further, the modified low molecular weight conjugated diene polymer of the present invention has a double bond in the molecular chain, and utilizing this, a crosslinking method used in a conventional diene polymer, that is, sulfur;
It is also possible to crosslink with peroxides such as dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, t-butyl peroxybenzoate and the like, and oximes such as quinone dioxime.

In that case, when sulfur is used, guanidines such as diphenylguanidine and diortitolylguanidine; thiazoles such as mercaptobenzothiazole and dibenzothiazyl disulfide; N-cyclohexyl-2-benzothiazyl sulfenamide; Vulcanization accelerators such as sulfenamides such as oxydiethylene-2-benzothiazyl sulfenamide, thiurams such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide, and vulcanization accelerators such as zinc oxide and stearic acid Used by adding an auxiliary agent and the like. When using oximes, lead compounds such as lead monoxide and lead trioxide are used as catalysts.

In the above, the modified low molecular weight conjugated diene polymer 100
0.1 to 20 parts by weight of a crosslinking agent based on the weight; a vulcanization accelerator,
The vulcanization accelerator aid and the catalyst are used in the range of 0.1 to 10 parts by weight.

The cross-linking reaction can be performed without any solvent when any cross-linking agent is used. When sulfur is used, the reaction is carried out at room temperature to 200 ° C. for 5 minutes to 3 days, and when peroxides are used, 100 to 200 days.
1 minute to 2 hours at room temperature, and normal temperature to 10 when using oximes.
Suitably, it is carried out at 0 ° C. for 1 minute to 3 days.

The modified low molecular weight conjugated diene-based polymer of the present invention is used as a cross-linked molded article as described above. In cross-linking, various compounding agents such as the above-mentioned cross-linking agent are usually added in view of the final use. Examples thereof include reinforcing agents and fillers such as carbon black, silica, calcium carbonate, and clay, process oils, softeners and plasticizers such as polybutene, DOP, and DOA, antioxidants, and ultraviolet absorbers.

Further, the modified low molecular weight conjugated diene-based polymer of the present invention can be used alone or mixed with another diene-based rubber to improve its adhesiveness and adhesion. As the diene rubber to be mixed at this time, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene copolymer rubber, or the like is used. In this case, in addition to the above-mentioned properties being imparted to the obtained mixture, a so-called reactive plasticizer in which the mixture is molded and vulcanized and then co-vulcanized to plasticize the mixture without causing a large decrease in mechanical properties. It also has the function of In addition, the modified low-molecular weight conjugated diene polymer of the present invention has increased polarity as a result of addition of a halogen atom and a carbonyl group, and thus has compatibility with thermoplastics that are not compatible with ordinary low-molecular weight conjugated diene polymers. It becomes possible to mix them, and for example, they are blended and used for the purpose of improving impact resistance, paintability and flexibility. The thermoplastics used herein include polystyrene, acrylonitrile-butadiene-
Styrene resin such as styrene resin, polyester resin,
Polycarbonate; polyolefin resin, (ethylene resin, etc.) and the like.

〔Example〕

Example 1 Isoprene was polymerized using n-BuLi to obtain a low molecular weight polyisoprene having a molecular weight of 37,000. Using this low molecular weight polyisoprene, the following cyclopropane ring introduction reaction was carried out.

After stirring, 27.25 g of the low molecular weight polyisoprene was dissolved in 40 g of hexane using a reactor equipped with a dropping device, and 50% NaOH aqueous solution and triethylbenzylammonium chloride were added and mixed to the solution under the conditions shown in Table 1. The temperature was raised to ° C. Then, chloroform was added dropwise with stirring at a rate of 40 C.C./hr to cause a reaction. After completion of the dropwise addition, the reaction was further performed for 2 hours. After completion of the reaction for a predetermined time, the reaction mixture was cooled, the aqueous layer was separated, and the organic layer was washed with water to remove NaOH and the like. Then, the organic layer was poured into a large amount of methanol to precipitate a reaction product, which was dried under vacuum to obtain a modified low molecular weight polyisoprene having a dichlorocyclopropane ring added. As a result of ¹³ C-NMR analysis of the obtained polymer, the absorption intensity at 130 ppm derived from the carbon-carbon double bond of the low-molecular-weight polyisoprene as a raw material was reduced, and instead, the carbon of the cyclopropane ring in which chlorine was added to 72 ppm was substituted. Atom-based absorption was observed, confirming the formation of the cyclopropane ring structure. In addition, as a result of chlorine analysis by the oxyhydrogen flame combustion method, the content of chlorine and the reaction rate thus calculated are shown in Table 1.

Example 2 A low molecular weight butadiene-isoprene block copolymer having a butadiene-isoprene-butadiene-isoprene structure was obtained by alternating polymerization of butadiene and isoprene with n-BuLi. The low molecular weight butadiene-
The molecular weight of the isoprene copolymer was 42,000, and the composition ratio of butadiene and isoprene was 30-20-30-20 (weight ratio of each block).

Using the above low molecular weight copolymer, a reaction for introducing a cyclopropane ring was carried out in the same manner as in Example 1 under the conditions shown in Table 2.

As a result of ¹³ C-NMR analysis of the obtained polymer, absorption based on the cyclopropane ring structure with chlorine added at 72 ppm appeared as in Example 1, and formation of the cyclopropane ring structure was confirmed. As a result of chlorine analysis by the oxyhydrogen flame combustion method, the chlorine content and the reaction rate calculated from it were as shown in Table 2.

Example 3 Polymerization was carried out in the same manner as in Example 1 to obtain low molecular weight polyisoprene having a molecular weight of 78,000.

Using the low molecular weight polyisoprene and the method shown in Example 1, a cyclopropane ring introduction reaction was carried out under the conditions shown in Table 3 using methyl chloroacetate instead of chloroform.

As a result of measuring ¹³ C-NMR of the obtained modified low-molecular-weight polyisoprene, the absorption intensity of 130 ppm derived from the carbon-carbon double bond of the low-molecular-weight polyisoprene as a raw material was decreased, and the carbon of carbonyl was replaced by 170 ppm. And the absorption based on the carbon of the cyclopropane ring to which a methoxycarbonyl group was added appeared near 27 ppm, confirming the formation of a cyclopropane ring structure.

As a result of measuring the infrared absorption spectrum, carbonyl-based absorption appeared around 1730 cm ^-1 , and the amount of cyclopropane ring introduced was determined from a calibration curve prepared separately using methyl acetate and polyisoprene.

 The results are shown in Table 3.

Example 4 Polymerization was carried out in the same manner as in Example 1 to obtain low molecular weight polyisoprene having a molecular weight of 53,000. Using this low molecular weight polyisoprene, a cyclopropane ring was introduced by the reaction shown below.

Using a stirrer and a reactor equipped with a dropping device, 25.0 g of the above low molecular weight polyisoprene was dissolved in 25 g of hexane,
Rhodium di-t-butanoate was added and mixed thereto under the conditions shown in Table 4, and the mixture was stirred at room temperature under a nitrogen atmosphere. Next, methyl diazoacetate was added dropwise at a rate of 70 g / hr under the stirring to cause a reaction. After the dropping was completed, the reaction was further performed for 1 hour. After completion of the reaction, the reaction mixture was poured into a large amount of methanol to precipitate the reaction product, which was dried in vacuum to obtain a modified low molecular weight polyisoprene having a cyclopropane ring having a methoxycarbonyl group added thereto.

As a result of ¹³ C-NMR analysis of the obtained polymer, the absorption intensity of 130 ppm derived from the carbon-carbon double bond of the low molecular weight polyisoprene as a raw material was decreased as in Example 3, and instead of 17
Carbon absorption of carbonyl appears around 0 ppm, and 27pp
Absorption based on carbon of the cyclopropane ring to which a methoxycarbonyl group was added appeared around m, confirming the formation of the cyclopropane ring structure.

Further, as a result of measuring an infrared absorption spectrum, absorption due to carbonyl appears at around 1730 cm ^-1 , and Example 3
The amount of cyclopropane ring introduced was determined by the calibration curve used in.

 The results are shown in Table 4.

Experimental Example 1 The modified low molecular weight polyisoprene obtained in Example 1 was used to evaluate the performance of a cured product (crosslinked product) and the adhesion to a metal by the following methods. Modified low molecular weight polyisoprene 11
5 parts by weight of magnesium oxide was added to 00 parts by weight, and a mixture was obtained by mixing at 60 ° C. The obtained composition was cast at a thickness of 2 mm and heated at 180 ° C. for 30 minutes to obtain a sheet-shaped cured product. Using this cured product, tensile properties were measured according to the method of JIS K-6301. The results are shown in Table 5. It can be seen from Table 5 that sufficient cured physical properties can be obtained. Further, the above composition was sandwiched between iron plates in an area of 1 mm thick and 5 × 5 cm, heated and cured at 180 ° C. for 30 minutes, and then the tensile shear adhesive strength was measured at a rate of 30 cm / min. The results are shown in Table 5, and it can be seen that the adhesive strength was sufficient.

Experimental Example 2 The modified low molecular weight polyisoprene obtained in Example 3 was used to evaluate the performance of a cured product (crosslinked product) and the adhesion to a metal by the following methods.

5 parts by weight of dicumyl peroxide was added to 100 parts by weight of modified low molecular weight polyisoprene and mixed at 80 ° C. to obtain a blend. The resulting blend was cast at a thickness of 2 mm and at 150 ° C
Heating was performed for 30 minutes to obtain a sheet-like cured product. Further, the above-mentioned composition was sandwiched between iron plates in the same manner as in Experimental Example 1 and heated at 150 ° C. for 30 minutes.
Using these, tensile properties and adhesive strength were measured in the same manner as in Experimental Example 1. The results are shown in Table 6, and it is found that they have sufficient cured physical properties and adhesive strength.

[Advantages of the Invention] The modified low-molecular weight conjugated diene-based polymer of the present invention does not impair the physical properties of the conventional low-molecular weight conjugated diene-based polymer, and has improved adhesiveness with materials such as metals and fibers. There is.

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Claims (5)

(57) [Claims] 1. A polymer selected from the group consisting of polyisoprene, a copolymer of two or more conjugated dienes, and a copolymer of a conjugated diene and another vinyl compound and having a molecular weight of 10,000 to 100,00.
When 1,4-bond content is 70 mol% or more, a part of the ethylenic double bond (C = C) of the low molecular weight conjugated diene polymer represented by the following formula is a halogen atom or an alkoxycarbonyl group. Added cyclopropane ring structure (Wherein _one of Y ₁ and Y ₂ is a halogen atom and the other is a halogen atom or a hydrogen atom, or one is an alkoxycarbonyl group and the other is an alkoxycarbonyl group or a hydrogen atom) Low molecular weight conjugated diene polymer. 2. The modified low molecular weight conjugated diene polymer according to claim 1, wherein the low molecular weight conjugated diene polymer is a low molecular weight polyisoprene or a low molecular weight polybutadiene-polyisoprene block copolymer. 3. The modified low molecular weight conjugated diene polymer according to claim 1, wherein the low molecular weight conjugated diene polymer is a polybutadiene-polystyrene block copolymer or a polyisoprene-polystyrene block copolymer. 4. The conversion rate of an ethylenic double bond to the cyclopropane ring structure is 0.05 to 50 mol% based on the diene unit of the low molecular weight conjugated diene polymer.
The modified low-molecular weight conjugated diene polymer according to the item. 5. The modified low molecular weight conjugated diene polymer according to claim 1, wherein the alkoxycarbonyl group is an alkoxycarbonyl group having 1 to 12 carbon atoms.