JP3341295B2 - Method for producing modified polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the glass transition temperature of a polymer by reacting a cyclopentadiene with a base polymer having a pendant double bond.

[0002]

2. Description of the Related Art Polymers having a pendant double bond represented by 1,2-polybutadiene resin, high vinyl polybutadiene rubber, high vinyl styrene / butadiene rubber and the like have been widely known. For example, 1,
Typical applications of 2-polybutadiene resin include stretch films, shrink films, laminate films, various tubes and hoses, adhesives, footwear, sponges,
Examples include various types of molded articles such as drawing cloth, vibration damping materials, automobile interior parts, and photosensitive resin materials. High vinyl polybutadiene rubber and high vinyl styrene / butadiene rubber are mainly used for tire applications.

In these fields of use, polymers having a glass transition temperature corresponding to the purpose of use are required. However, it is difficult to arbitrarily control the glass transition temperature. There was no efficient way to improve.

[0004]

Accordingly, the present inventors have conducted intensive studies on a method for improving the glass transition temperature of a base polymer. As a result, the inventors have found that a polymer having a pendant double bond is reacted with a cyclopentadiene. ,
The present inventors have found that the pendant double bond and the cyclopentadiene efficiently perform a Diels-Alder reaction and can adjust the glass transition temperature to a desired value, and have completed the present invention.

[0005]

Thus, according to the present invention, a cyclopentadiene is reacted with a base polymer having a pendant double bond, and cyclopentadiene is added to the pendant double bond by a Diels-Alder reaction. A method for producing a modified polymer is provided.

(Base Polymer) The base polymer of the present invention is a polymer having a pendant double bond in a side chain. Any of resin, rubber, and liquid may be used. The pendant double bond is usually introduced by using a diene as a monomer component. Specific examples of preferred dienes include, for example, butadiene, isoprene,
Examples include 1,3-pentadiene and chloroprene. However, the base polymer of the present invention is not necessarily limited to a conjugated diene-based polymer, and may include a non-conjugated diene as a monomer component.

The base polymer of the present invention has a proportion of a repeating structural unit having a pendant double bond of 1% by weight or more, preferably 20% by weight or more, more preferably 30% by weight or more. Other repeating structural units are
It may be a repeating structural unit derived from a copolymer component or a repeating structural unit having no pendant double bond derived from a diene. If the amount of the repeating structural unit having a pendant double bond is small, the amount of cyclopentadiene added to the base polymer is small, and the effect of improving the glass transition temperature cannot be obtained.

[0008] As the copolymerization component, for example, styrene, α
-Styrenes such as methylstyrene, acrylonitrile, ethyl acrylate, ethylene, nitroethylene, methyl methacrylate, ethyl methylene malonate, vinylidene cyanide and the like can also be used.

The method of polymerizing these monomers is not particularly limited, and known methods such as a method using an alkyl lithium, an alkyl sodium or the like as a catalyst, a method using a catalyst comprising a cobalt carbonyl complex and a molybdenum halide or the like are used. I just need. The selection of the catalyst changes the amount of the repeating structural unit having a pendant double bond. It is preferable to select the most suitable catalyst in consideration of the amount of the copolymer component, the reaction efficiency, the amount of the repeating structural unit having a pendant double bond, and the like.

The molecular weight of the base polymer of the present invention is 500
~ 500,000, preferably 5,000 ~ 200,0
00, more preferably 10,000 to 100,000.

(Addition of Cyclopentadienes) In the present invention, cyclopentadienes are added to the pendant double bond of the base polymer by a Diels-Alder reaction.

The cyclopentadiene referred to in the present invention is
The term refers to cyclopentadiene or an alkyl-substituted product thereof, and specific examples thereof include cyclopentadiene and methylcyclopentadiene.

Cyclopentadienes easily dimerize at room temperature into dicyclopentadienes. When the dicyclopentadiene is thermally decomposed, the cyclopentadiene is regenerated. To add the cyclopentadiene to the base polymer, a mixture of the dicyclopentadiene and the base polymer is heated at a temperature at which the dicyclopentadiene is thermally decomposed to form the cyclopentadiene, usually 180 to 25.
Heat to 0 ° C, preferably 190-240 ° C, more preferably 200-230 ° C. If the heating temperature is too low,
The thermal decomposition of dicyclopentadiene becomes difficult to occur, and the reactivity decreases. Conversely, if the heating temperature is too high, it becomes difficult to control the reaction. The pressure condition of the reaction is not particularly limited,
Usually, it is preferable to select from the range of 1 to 50 kg / cm ² .

This heating reaction is usually preferably carried out in an inert organic solvent. As the inert organic solvent,
Aromatic hydrocarbons such as benzene, toluene and xylene;
Alicyclic hydrocarbons such as cyclohexane; halogenated hydrocarbons such as methylene dichloride, dichloroethane, dichloroethylene, tetrachloroethane, chlorobenzene, dichlorobenzene, and trichlorobenzene; and the like, and mixtures of two or more thereof. You may use it.

The proportion of the base polymer and the dicyclopentadiene used is usually 1 to 100 mol, preferably 2 to 80 mol, more preferably 1 to 100 mol, per 100 mol of the vinyl group contained in the base polymer. Preferably it is 5 to 50 mol. The greater the proportion of dicyclopentadiene used, the greater the amount of dicyclopentadiene added to the base polymer. If the proportion of the dicyclopentadiene is too small, the effects of the present invention cannot be obtained. If the use ratio of dicyclopentadiene is too large,
Along with the addition reaction of the cyclopentadiene to the base polymer, the multiplying reaction of the cyclopentadiene itself proceeds, so that it becomes an impurity which is difficult to remove.

The cyclopentadiene is added not only to the pendant double bond of the base polymer but also to the double bond of the cyclopentadiene already added. As a result, the pendant double bond of the base polymer may have a structure in which a polymer of cyclopentadiene is added in addition to cyclopentadiene.

(Modified Polymer) The modified polymer of the present invention thus obtained has cyclopentadiene added to the pendant double bond of the base polymer by a Diels-Alder reaction, and has a glass transition temperature higher than that of the base polymer. high. The glass transition temperature of the modified polymer increases as the amount of added cyclopentadiene increases. In order to adjust the amount of cyclopentadiene added, for example, the charging ratio and the reaction time may be adjusted. The longer the reaction time, the greater the amount of cyclopentadiene added.
The modified polymer is not limited to one in which one molecule of cyclopentadiene is added to a pendant double bond, but also includes one in which two or more molecules of cyclopentadiene are added.

The modified polymer of the present invention generally contains substantially no gel and is soluble in a suitable solvent. For example, it is completely dissolved in toluene at 50 ° C.

In the modified polymer of the present invention, if desired,
Antioxidants such as phenol and phosphorus; thermal deterioration inhibitors such as phenol; ultraviolet stabilizers such as benzophenone; antistatic agents such as amine; esters of aliphatic alcohols and partial esters and partial esters of polyhydric alcohols Various additives such as a lubricant such as ether; and the like may be added.
In addition, other resins, rubbers, and the like can be mixed and used as long as the object of the present invention is not impaired. Further, if the molded article does not require transparency, various fillers can be used for the purpose of improving the strength and the like.

Since the modified polymer of the present invention can control the glass transition temperature, it can have heat resistance according to the purpose of use. The resin can be used after being molded into a transparent sheet or the like, and the rubber can be used for tire applications and the like.

[0021]

The present invention will be described more specifically with reference to examples, comparative examples and reference examples. Parts are by weight unless otherwise specified.

REFERENCE EXAMPLE 1 50 parts of butadiene and 950 parts of cyclohexane were placed in a reactor which had been sufficiently dried and purged with nitrogen.
10.8 parts of tetramethylethylenediamine and 2.2 parts of n-butyllithium were added, and polymerization was carried out while maintaining the reaction system at 40 ° C. After terminating the polymerization with methanol, the reaction solution was poured into 2000 parts of isopropyl alcohol to coagulate polybutadiene. The coagulated polybutadiene was reduced in pressure to about 50 torr with a vacuum drier, dried at 80 ° C. for 2 days to obtain 45 parts of polybutadiene.

The obtained polybutadiene had a number average molecular weight of 21,000, a weight average molecular weight of 49,000 and a glass transition temperature of -29.5 ° C. FIG. 1 shows the infrared absorption spectrum of this polybutadiene. At 911 cm ^-1 , absorption due to a vinyl group was observed. From comparison with other absorptions, 6
It was found that 3.4% were repeating structural units having a vinyl group in the side chain.

Example 1 50 parts of the polybutadiene obtained in Reference Example 1 and 15 parts of dicyclopentadiene were dissolved in 200 parts of cyclohexane and reacted at 230 ° C. for 6 hours. The reaction solution was poured into 1000 parts of isopropyl alcohol to coagulate the polymer, and the mixture was filtered off.
After vacuum drying for a time, a resin was obtained.

The obtained resin had a yield of 51 parts and a glass transition temperature of 9.1 ° C. FIG. 2 shows the infrared absorption spectrum of this resin.

At 720 cm ^-1 , absorption due to an intra-ring double bond of cyclopentadiene was observed. The infrared absorption spectrum analysis of the vinyl norbornene, the absorbance of 911 cm ^-1 attributable to a vinyl group (D ₉₁₁₎ and the absorbance of 720 cm ^-1 due to the endocyclic double bond of the norbornene skeleton (D
₇₂₀ ) was 1: 1.19, which means that 911c
Based on the absorbance at m ^{-1 and} the absorbance at 720 cm ^-1 , the ratio of the cyclopentadiene-added vinyl group to the total vinyl group before addition (cyclopentadiene addition ratio) was calculated as D ₇₂₀ /
The result calculated as (D ₇₂₀ + D ₉₁₁ × 1.19) is 2
2.3%.

Reference Example 2 43 parts of polybutadiene were obtained in the same manner as in Reference Example 1, except that the amount of tetramethylethylenediamine used was changed to 35.9 parts.

The resulting polybutadiene had a number average molecular weight of 23,000, a weight average molecular weight of 50,000, and a glass transition temperature of -29.3 ° C. FIG. 3 shows the infrared absorption spectrum of this polybutadiene. At 911 cm ^-1 , absorption due to a vinyl group was observed. From comparison with other absorptions, 7% of all polybutadiene repeating units were found.
0.8% was found to be a repeating structural unit having a vinyl group in the side chain.

[Example 2] The polybutadiene obtained in Reference Example 2 was used in place of the polybutadiene obtained in Reference Example 1, and an addition reaction was carried out in the same manner as in Example 1, and the reaction was carried out for 3 hours, 7 hours, 11 hours, and 23 hours. Then, a resin was obtained in the same manner as in Example 1, and the glass transition temperature was measured and the infrared absorption spectrum was analyzed.

The polymer obtained by reacting for 23 hours had a yield of 52 parts and a glass transition temperature of 2.5 ° C. FIG. 4 shows the infrared absorption spectrum of this resin. 720 cm ^-1
The absorption due to the double bond in the ring of cyclopentadiene was observed, indicating that cyclopentadiene was added to the base polymer. Table 1 shows the addition ratio of cyclopentadiene to the vinyl group at each reaction time calculated in the same manner as in Example 1.

[0031]

[Table 1]

From these results, it can be seen that Tg increases as the addition of cyclopentadiene to the vinyl group progresses.

[0033]

According to the present invention, a modified polymer having a glass transition temperature according to the intended use can be obtained by reacting a cyclopentadiene with a base polymer having a pendant double bond.

[Brief description of the drawings]

FIG. 1 is an example of an infrared absorption spectrum of a base polymer in the present invention.

FIG. 2 is an example of an infrared absorption spectrum of a modified polymer according to the present invention.

FIG. 3 is another example of the infrared absorption spectrum of the base polymer in the present invention.

FIG. 4 is another example of an infrared absorption spectrum of the modified polymer according to the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-143892 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 8/00-8/50

Claims (1)

(57) [Claims] 1. A method for producing a modified polymer, comprising reacting a cyclopentadiene with a base polymer having a pendant double bond, and adding the cyclopentadiene to the pendant double bond by a Diels-Alder reaction. .