JPH0326710A - Stable conjugated diene-based copolymer - Google Patents

Abstract

PURPOSE:To obtain the subject novel copolymer, composed of conjugated diene units and p-alkenylphenol units in a specific proportion, having H, OH and/or COOH at molecular terminals and excellent in stability to oxygen and heat and further thermal decomposition characteristics. CONSTITUTION:The objective copolymer composed of a random copolymer, partial block copolymer, complete block copolymer or graft copolymer, containing (A) conjugated diene units and (B) p-alkenylphenol units as recurring units, having H, OH and/or COOH at molecular terminals and the molar ration of the units (A) to (B) satisfying the formula with 5000-100000 number-average molecular weight. Furthermore, the above-mentioned copolymer is preferably obtained by copolymerizing 1,3-butadiene and/or isoprene as the conjugated diene compound with p-methoxystyrene, etc., and then eliminating saturated aliphatic groups from the resultant product with an acidic reagent.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a novel conjugated diene-based copolymer, and more specifically, a conjugated diene-based copolymer having a conjugated diene unit and a p-alkenylphenol unit as repeating units. Regarding copolymers.

The conjugated diene copolymer of the present invention has excellent stability against heat and oxygen, and is therefore expected to be used in a wide range of fields as a modifier for thermosetting resins and thermoplastic resins. [Prior art] Low molecular weight conjugated diene polymers with a number average molecular weight of about 500 to 10,000 have excellent water resistance, electrical properties,
Due to its flexibility and thermal shock resistance, it is widely used as a main ingredient in thermosetting resin compositions such as paints, adhesives, impregnation agents, casting materials, and laminated materials.

On the other hand, conjugated diene polymers with a number average molecular weight of tens of thousands or more have excellent rubber elasticity, strength, low-temperature impact resistance, and are also excellent in safety and hygiene, so they are used as thermoplastic elastomers.
, P.P. It is used in the field of resin modifiers such as PS resins, adhesives, adhesives, miscellaneous goods, etc. In these conventional techniques, for the purpose of improving the stability of resins or resin compositions, there are methods of adding oxidation (polymerization) inhibitors to polymers, and methods of adding oxidation (polymerization) inhibitors to conjugated diene polymers by hydrogenation. A method of saturating and inactivating active double bonds (see JP-A-49-023298 and JP-B-50-014277) has been adopted. On the other hand, polymers of p-alkenylphenol, such as p-vinylphenol, are usually used as curing agents for resist materials and epoxy resins, and are also effective as antioxidants and thermal deterioration inhibitors for resins. It is known that (JP-A-51-020247, JP-A-54-
(See Publication No. 014451, etc.) [Problems to be Solved by the Invention] Conjugated diene polymers have a large amount of active double bonds in their main chains or side chains, so they tend to gel during their modification reactions. Also, under the influence of oxygen and heat, the composite material gradually loses its original flexibility and becomes brittle.

As the above-mentioned oxidation (polymerization) inhibitor, phenol, amine, sulfur, phosphorus, etc. are usually added in an amount of 0.05 to 2.0% by weight to the conjugated diene polymer to prevent deterioration. The effect of preventing thermal polymerization at high temperatures is not sufficient, and the sustainability of the effect of preventing oxidative deterioration is insufficient even near room temperature.

On the other hand, in the method using hydrogenation, the stability against heat and oxygen improves over time, but the structure of the polymer chain after hydrogenation changes to a polyethylene/poly-α-olefin type, which significantly lowers the thermal decomposition temperature. The hydrogenation reaction not only requires an expensive catalyst but also requires complicated post-treatment. In addition, p-alkenylphenol polymers are almost incompatible with commercially available conjugated diene polymers, so it is difficult to incorporate them into conjugated diene polymers to improve their stability against heat and oxygen. Have difficulty.

An object of the present invention is to provide a conjugated diene copolymer that has excellent stability against oxygen and heat and excellent thermal decomposition properties.

[Means for solving problems]

As a result of intensive research aimed at achieving the above-mentioned objective, the present inventors discovered that by introducing a p-alkenylphenol skeleton into a conjugated diene copolymer, the double bond is inactivated, resulting in stability against heat and oxygen. They found that the properties of this invention were significantly improved and perfected the present invention. In the present invention, A: a conjugated diene unit and B: a p-alkenylphenol unit are used as repeating units, and the molecular terminal is -H
, -OH and -COOH, and the molar ratio of A and B is 0.5≧
B/ (A+B)≧O. O O 5, one type selected from the group consisting of a random copolymer of A and B having a number average molecular weight of 500 to 100,000, a partial prosodic copolymer, a complete block copolymer, and a graft copolymer It is a stable conjugated diene copolymer characterized by:

In the present invention, A: conjugated diene unit is represented by the following general formula +
11 and (2) -←--C Ht -C H = C-C HX
-One → One? 1 ~<----CI■ 11C1→--1-11・- (
2) R core - C material CH. (Here, Rl and Rz represent hydrogen or a methyl group.) It is at least one type from the group consisting of butadiene units and isoprene units represented by the following.

Specifically, 1,2-butadiene units, 1,4-butadiene units, 1,11-isogrene units, 1,4-isoprene units, and 3,4-isogrene units may be mentioned, and two or more of these units may be used. It may be 12. In addition, B: alkenyl (alkyl) phenol unit is a p-vinylphenol unit represented by the following general formula (3) R10H (wherein R represents hydrogen or a methyl group) and /or p-isobropenylphenol unit.

The conjugated diene copolymer of the present invention is a random copolymer in which repeating units with A and B are statistically uniformly distributed in the polymer chain, and polymers in which A or B is a repeating unit. It includes partial block copolymers partially having chains, complete block copolymers in which polymer chains having A or B as repeating units are regularly repeated, and graft copolymers.

In the conjugated diene copolymer of the present invention, the above A:
The molar ratio of the conjugated diene unit and the B: alkenylphenol unit affects its oxidation (polymerization) prevention property, rubber elasticity, heat impact resistance, etc. If it is too small, the oxidation (polymerization) prevention property decreases, If the amount is too large, the inherent properties of the conjugated diene copolymer, such as rubber elasticity and thermal shock resistance, will be degraded. Preferred A
The molar ratio of B and B is 0. 5 and B/A+B book 0. O
O5, more preferably 0. 2≧B/A10B
≧0. Also, the number average molecular weight (1n) of the conjugated diene copolymer is 500 to 100.
0 0 0, and has a molecular weight distribution in which the ratio of weight average molecular weight (Mw) to number average molecular weight is Mw/Mn=3.0 or less, especially 1,000. $Mn≦50, 0 0
0, Mw/Mn=2. It is preferably 0 or less. The conjugated diene copolymer of the present invention can be produced by the following method. Conjugated diene compounds such as 1,3-butadiene, isoprene, 2,3-dimedyl-1,3-butadiene, 1.
3-pentadiene etc. and the following general formula (3)R. (Here, R represents the same meaning as above, and R4R and R represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and may be the same or different from each other.) A compound (hereinafter referred to as "phenol precursor") is copolymerized by a known anionic polymerization method or radical polymerization method, and then an acidic reagent is applied to remove the saturated aliphatic group.

As conjugated diene compounds, 1,3-butadiene and isoprene are preferably used, either alone or as a mixture.

A: The micro fJI structure of the conjugated diene unit is n depending on the polymerization method and the conjugated diene compound used. When butadiene is used, 1,2-bond and /mano,= are 1,4-bond; when isoprene is used, l,2-bond, 1
．． 4-bonds and/or 3,4-bonds are formed, and their ratio varies depending on the polymerization method, reaction conditions, etc., but is not particularly limited in the present invention. p-methoxystyrene, p-
Examples include n-buty-xystyrene, p-t-butoxystyrene, p-t-buty-α-methylstyrene, and these can also be used singly or as a mixture of two or more.

When anionic polymerization is employed as a polymerization method, a conjugated diene compound and a phenol precursor are polymerized in an aqueous solvent in an atmosphere of an inert gas such as nitrogen or argon, using an alkali metal or an organic alkali metal as a polymerization initiator, -100
The polymerization reaction is carried out at a temperature of ~+150°C. As the alkali metal of the polymerization initiator, lithium, sodium, potassium, etc. are used, and as the organic alkali metal, alkylated products, allylated products, arylated products, etc. of the above-mentioned alkali metals are used. Examples of these organic alkali metals include ethyllithium, n-butyllithium, sec-
Butyl lithium, t-butyl lithium, ethyl sodium, butadienyl dilithium, butadienyl disodium, lithium biphenyl, lithium naphthalene, lithium triphenyl, lithium fluorene, sodium biphenyl, sodium naphthalene, sodium triphenyl, sodium fluorene, α -methylstyrene sodium dianion, etc., and these l types can be used alone or in a mixture of two or more types. As a reaction solvent, aliphatic hydrocarbons such as n-hexane and n-heptane, alicyclic hydrocarbons such as cyclohexane and cyclobencune, aromatic hydrocarbons such as benzene and toluene, diethyl ether, tetrahydrofuran, etc. Ethers can be used singly or as a mixture of two or more. The introduction of the functional Ti1 group to the end of the polymer chain can be achieved by treating the reaction solution after the polymerization reaction with carbon dioxide or a cyclic ether compound such as ethylene oxide, and then with water or methanol.
(-COOH) and a water III group (-0H) are introduced. When radical polymerization is employed, as a polymerization initiator, organic peroxides such as benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, 1,1-bis(t-butylperoxy)cyclohexane, azobis Using azo compounds such as isoptylonitrile and azobis-2,4-dimethylvaleonitrile, a polymerization reaction is carried out in an organic solvent under the above-mentioned inert gas atmosphere at a temperature of room temperature to 200°C. In this case, as the organic solvent, in addition to the solvent used in the anionic polymerization, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and butyl acetate, and alcohol solvents such as ethanol and isopropanol can also be used. ．． Introduction of a functional group to the terminal end of the polymer can be carried out by introducing a hydroxyl group when hydrogen peroxide is used as a polymerization initiator, or by introducing a hydroxyl group into a polymerization initiator having a functional group, such as azobis-4-cyanobentanol, azobis-4-cyanovalerisotin, etc. When acidodo is used, a water M group and a carboxyl group are introduced, respectively. Furthermore, when an azo compound such as abbisisobutyronitrile or azobis-2,4-dimethylbarekonitrile is used together with a mercaptan containing a functional group such as mercabutoethanol or thioglycolic acid as a polymerization initiator, each hydroxyl group , a carboquine group is introduced.

As a copolymerization method for these conjugated diene compounds and phenol precursors, the above-mentioned anionic polymerization method is more preferably employed because it allows easy control of molecular weight and functional groups and provides a monodisperse polymer with a narrow molecular weight distribution. The copolymer of the conjugated diene compound and the phenol precursor obtained by the above polymerization method (hereinafter referred to as the "intermediate copolymer") is treated with a chlorinated solvent such as the solvent exemplified in the polymerization reaction or carbon tetraride. In the presence of hydrochloric acid, hydrogen chloride gas, hydrobromic acid, 1,1
．． By adding at least one acidic reagent such as 1-1-lifluoroacetic acid and performing a dealkylation reaction at a low temperature, usually below 100°C, a p-alkenylphenol skeleton is generated, and the conjugated diene of the present invention is produced. A system copolymer is obtained. In this reaction, side reactions such as polymer chain scission and intermolecular crosslinking hardly occur, and the molecular weight distribution hardly changes before and after the reaction. Furthermore, by selecting the method of adding the conjugated diene compound and the phenol precursor during polymerization of the intermediate copolymer,
Random copolymers, partial pro-7 copolymers, and complete block copolymers can be produced. For example, a random copolymer can be created by polymerizing a conjugated diene compound and a phenol precursor in a completely mixed state. By adding and polymerizing a mixture of
Furthermore, after polymerizing either the conjugated diene compound or the phenol precursor, a complete block copolymer can be obtained by adding the other to complete the polymerization. [Function] As described above, the conjugated diene copolymer of the present invention has A:
It has a main chain skeleton consisting of a conjugated diene unit and a B:p-alkenylphenol unit as repeating units, and has hydrogen (-H), hydroxyl i (101{〉) or carboxyl group (
-COOH). In the conjugated diene copolymer of the present invention, the p-alkenylphenol unit, which has a large oxidation (polymerization) prevention effect, is
Because it is present in the main chain skeleton, the double bonds in the conjugated diene units are more completely inactivated than when an oxidation (polymerization) inhibitor is simply added to the conjugated diene polymer.
Therefore, the stability of the conjugated diene copolymer against heat and oxygen is significantly improved. In addition, when modifying other resins, such as polyester resins and polyamide resins, using the functional groups at the end of the main chain of this copolymer, polymerization and gelation during the reaction are possible due to its excellent high temperature stability. It is possible to obtain a modified product which can prevent side reactions such as, maintain initial properties such as flexibility, rubber elasticity, thermal shock resistance, etc., and has excellent stability against heat and oxygen.

〔Example〕

The present invention will be explained in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited in any way by the following examples.

In addition, in the following examples, "parts" and "%" are based on weight unless otherwise specified.

(1) Production of intermediate copolymer (al sample: M-1 In a nitrogen atmosphere, 225% of a tetrahydrofuran (THF) solution containing 10 mmol of sec-butyllithium
g and a 40% THF solution containing 3.5 g of p-tert-butoxystyrene (trade name: Hokuko I) (manufactured by Hokko Chemical) were polymerized by stirring and holding at -40°C for 1 hour. After that, a 40% THF solution containing 27 g of 1,3-butadiene was added, and the mixture was further heated at -40°C for 3
The mixture was kept stirring for an hour. Then, methanol was added to stop the polymerization, and the solvent was distilled off under reduced pressure to obtain 30 g of an intermediate copolymer (Sample 2 M1).

Regarding the obtained M~1, the number average molecular weight was measured by the VPO method and was found to be 3,150. In addition, as a result of analysis by GPC, the elution curve showed that the weight average content was 7-M (Monichi).
/ number average molecular weight (mono n) = 1.06 was obtained, showing excellent monodispersity. and a 40% THF solution containing 6.0 g of p-tert-butoxystyrene (above) and 24 g of 1.3-butadiene were stirred and held at -40°C for 4 hours, then methanol was added to stop the polymerization, The intermediate copolymer (sample:
M-2) 30g was obtained. The obtained M-2 had a number average molecular weight of 6.280,
Mw/Mn=1. It was a copolymer with excellent OS monodispersity. fcl Sample 2 M-3 Under a nitrogen atmosphere, 230 g of a THF solution in which a sodium-kerosene dispersion containing 31.4 mmol of sodium was dispersed and p-tart-butoxystyrene (described above)
40% containing 5.0g and 25g of 1,3-butadiene
After stirring and holding the THF solution at -65°C for 4 hours, methanol was added to stop the polymerization, and the solvent was distilled off under filtration pressure to obtain an intermediate copolymer (sample: M-3). .

Obtained f. - M-3 is a number average molecule 1tl, 980.
．． Mw/Mn-1. It was a copolymer with excellent monodispersity. (d+ Sample: M-4 In a nitrogen atmosphere, 300 g of a THF solution containing 10 mmol of n-butyllithium and a 40% THF solution containing 4.0 g of p-tart-butoxystyrene (described above) were heated at -40°C. After polymerization by stirring for 2 hours,
A 40% THF solution containing 26 g of 1,3-ptadiene was added, and the mixture was kept stirring at -40°C for an additional 3 hours. The reaction solution was then treated with a large excess of dry ice and further treated with a 10% hydrochloric acid-methanol solution, and the solvent was distilled off under reduced pressure to obtain an intermediate copolymer having a carboxyl group at the molecular end (sample: M-4) 29.7g was obtained. The obtained M-4 is a number average molecule! 3,030, Mw/M
n=1. 0 3, acid value -1 6.7 (KOHm
It was a copolymer with excellent monodispersity (g/g). +111 Sample 2 M-5 In an autoclave, 400 g of cyclohexane, THF
8g, n-butyllithium 4.8ξ mol, 1.3-butadiene 70g and p-tart butoxystyrene (
After charging 30 g of the above) and carrying out a polymerization reaction at 60°C for 4 hours under a nitrogen atmosphere, the reaction solution was poured into a large amount of methanol to stop the polymerization reaction, and then the solvent was distilled off under reduced pressure. 98.5 g of intermediate copolymer (sample: M-5) was obtained.

The obtained M-5 had a number average molecular weight of 20,700, Mw/
Mn=1. It was a monodispersed copolymer of 0.06.

ff) Sample: M-6 Into an autoclave, 400 g of cyclohexane, 2.5 mmol of n-butyllithium, and 80 g of isoprene were charged, and after stirring and holding at 60°C for 3 hours in a nitrogen atmosphere, p-tert-butoxystyrene ( 20g of the above) was added, and the reaction was continued for an additional 2 hours.Then, the reaction solution was poured into a large amount of methanol to stop the polymerization reaction.
The solvent was distilled off under reduced pressure to obtain an intermediate copolymer (sample: M-6).
97g was obtained. The obtained M-6 has a number average molecular weight of 133,300, Mw/
It was a monodisperse copolymer with Mn=LO8.

{2} Synthesis sample of conjugated diene copolymer: C-1-
C-6 Copolymer samples synthesized in the above [11]: M-1 to M-
6 were respectively dissolved in dioxane to make a 10% solution, and the solutions of M-1 to M-3 were reacted for 15 minutes at room temperature while blowing hydrogen chloride gas, and then M-
For solutions of 4 to M-6, add concentrated hydrochloric acid and heat to 60℃ for 3
After reacting for a time, the solvent was distilled off under reduced pressure to obtain conjugated diene copolymer samples: C-1 to C-6.

Judgment based on the method of L, M. Kolthoff et al.+Cl number average molecule! (Mn) Measured using vpo (dl Weight average molecular weight (Mw) / Number average molecular weight (
Mn) Calculated from GPC elution curve The above characteristics are shown in Table 1 together with elemental analysis values.

The following characteristics were measured for the obtained C-1 to G-6. ta+ Microstructure: Analysis by infrared absorption spectrum fbl Copolymerization form: Journal of Polymer Science (J. Po
lymer Sci. + 1, 429, (1946
)) Also, intermediate copolymer samples: M-1-M-6
As a result of comparing the infrared & lIW & yield spectrum curves of and conjugated diene copolymer samples 8C-1 to G-6, 1, 160 cm-' derived from the tert to butoxy groups present in the intermediate copolymer, respectively. and 1,360c
The m-' absorption disappeared in the conjugated diene copolymer, and a new I-code absorption derived from the hydroxyl group was observed around 3,300 cm-'.

CPC measurement comparing each sample of the intermediate copolymer and each sample of the conjugated diene copolymer (see attached Figures 1 to 3)
In }, almost no changes were observed in both the discharge position and molecular weight distribution (Mw/Mn). Furthermore, the number average molecular weight and elemental analysis values for each sample of the conjugated diene copolymer were in good agreement with the expected values.

From the above, the polymerization reaction of the intermediate copolymer progressed as planned.
In addition, these debutylation reactions proceed without any side reactions, and the desired conjugated diene copolymer having repeating units A: conjugated diene unit εB: p-alkenylphenol unit can be obtained. It was confirmed that (3rd thermal stability test Each sample of the conjugated diene copolymer synthesized in the above (2nd item): C-1 to C-6 and the following comparative samples CX1 to Cχ
-6, thermogravimetric analysis (TGA) differential thermal analysis (DT
A) Stability tests were carried out at i180'c in air and in nitrogen; 250°C.

The test results are shown in Table 2. [Comparative sample] CX-11.2-polybutadiene (number average molecular weight 3.0
40, 1.2 = bond content 89.9%, product name: NrS
SO-P [l-G-30 (IQ Nippon Soda ■) CX-2: 1,4-polybutadiene (number average molecular weight 2,
800, 1.4 = bond content 80%, product name - Pol
yBD-R45H, manufactured by Idemitsu Petrochemical ■> CX-3: Intermediate copolymer sample synthesized in the above section 1: M-1 CX-4: Intermediate copolymer sample synthesized in the above section (1) :M-5 CX-5: Hydrogenated polybutadiene (number average molecule W3,
100, hydrogenation rate 97.5%, product name: NISSO-
PB-Gl-3000, manufactured by Nippon Soda ■) CX-6: CX-1 with an oxidizing antistatic agent (thiophyl 14
Nord type, product name: Sumilizer 11 χ-R, special product of Sumitomo Chemical) [Test conditions] (a) TGA: Sample amount 1 (1 + g, heating rate 10'C/min, atmosphere: thermal decomposition temperature under air conditions) Measured (blDTA: Under the same conditions as TGA, measured the exothermic onset temperature due to oxidative polymerization 6 and exothermic fi! (comparative sample: comparative value with CXL as 100) (Cl in air; 180 ° C stable steel plate) Each sample was applied to a film thickness of approximately 50 μm,
Leave it in an oven set at 180°C in an air atmosphere,
Observe the state of dryness to the touch every 10 minutes, and measure the time until it becomes non-adhesive (=gelling) (in nitrogen; stability at 250°C. Approximately 5 g of sample was placed in a 10 cc test tube and heated at 250° C. in a nitrogen atmosphere. Samples 20-2, C-3, and C-5 were left in an oven set at ℃, and their fluidity was observed every 30 minutes. After measuring GPC and comparing it with the initial value, as shown in Part 2, each sample of the conjugated diene copolymer of the present invention has extremely excellent thermal properties and Indicates thermal stability.Also, hydrogenated polyptadiene comparison sample rl:
(J-5J) Since there are no active double bonds in the molecule, it exhibits low thermal stability, but its ripening temperature is low. [Effects of the Invention] The conjugated diene copolymer of the present invention As shown in the above example, the coalescence not only has excellent chemical monodispersity, but also
Excellent heat resistance and thermal stability in air and nitrogen atmospheres. In other words, even when exposed to heat and oxygen atmospheres for long periods of time, there is almost no change over time such as loss of fluidity or flexibility due to surface oxidation or thermal polymerization.゜These effects are achieved by introducing a relatively small amount of alkenylphenol units into the polymer having conjugated diene units as repeating units. There is almost no deterioration in properties such as elasticity, moisture resistance, rubber elasticity, and thermal shock resistance. Furthermore, by utilizing these properties, it has excellent heat resistance and stability even when added to different types of resins at high temperatures, or when performing modification reactions of different types of resins using the functional groups at the end of the polymer chain. Therefore, these modifications can be carried out without causing undesirable side reactions such as gelation. Therefore, the conjugated diene copolymer of the present invention can exhibit excellent electrical properties, water resistance, moisture resistance, rubber elasticity, thermal shock resistance, etc. by itself, by adding it to a different resin, or by introducing it into a different resin skeleton. It can be used to prepare various resin materials, and can be applied to a wide range of thermoplastic resins and thermosetting resins.

INDUSTRIAL APPLICABILITY The present invention provides a conjugated diene copolymer with improved stability against heat and oxygen, and has great significance in industry, particularly in the field of resin materials. 4

[Brief explanation of drawings]

Figures 1 to 3 show the CPC outflow curves of the conjugated diene copolymer samples C-1, C-2, and C-5 obtained in Examples before and after the high-temperature storage test. Figure 1 Sample: c-i+a+ before test (second after bl test)
Figure Sample: Before C-2fal test (Figure 3 after BL test
Sample ic-sta + before test (bl vC after test patent issued I
M (430) Representative of Nippon Soda Co., Ltd. (7125) Yoshi Yokoyama
Beauty (9 6 4 B) Hiroshi Tokai
Work 20 19 18 17 16EC

Claims (4)

[Claims] (1) A: conjugated diene unit and B: p-alkenylphenol unit are the repeating units, and the molecular terminal is -H,
-OH and -COOH, and the molar ratio of A and B is 0.5≧B/(A
+B)≧0.005, number average molecular weight is 500 to 100,
A stable conjugated diene system characterized by being one selected from the group consisting of a random copolymer, a partial block copolymer, a complete block copolymer, and a graft copolymer of A and B of 000. copolymer (2) A conjugated diene copolymer according to claim (1), wherein A: the conjugated diene unit is at least one selected from the group consisting of butadiene units and isoprene units. (3) In claim (2), the butadiene unit is
Conjugated diene copolymer characterized by 1,2-bonds and/or 1,4-bonds (4) In claim (2), the isoprene unit is
Conjugated diene copolymer characterized by having 1,2-bonds, 1,4-bonds and/or 3,4-bonds