JPS634561B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a cyclized polymer using, as a starting material, a low molecular weight isoprene polymer modified with a compound having a specific functional group. Natural rubber (NR) and synthetic isoprene rubber (IR)
Isoprene-based rubbers such as these are easily cyclized in the presence of acidic catalysts, and the resulting cyclized rubbers have excellent adhesion to polyolefins, adhesion to metals, etc., abrasion resistance, chemical resistance, etc. It has the following characteristics and has been used in adhesives, paints, vehicles for printing inks, electrical insulation materials, etc. Furthermore, in recent years, attempts have been made to apply it to photosensitive materials because it has a highly reactive double bond in its molecular chain. However, natural rubber (NR) and synthetic isoprene rubber (IR), which have traditionally been used as starting materials for cyclized polymers, are polymers with extremely high molecular weights, have extremely poor dissolution workability, and are difficult to handle in cyclization reactions. Even if it were attempted, it had to be done at a low concentration, and the productivity was extremely low. In addition, cyclized rubbers produced by reactions at low solid content without regard to productivity not only have considerably poor compatibility with highly polar resins such as alkyd resins, but also have poor compatibility with polyolefins and other highly polar resins. Adhesion to metals was also not always sufficient. In order to overcome these drawbacks, various proposals have been made to use low molecular weight rubbers, but the cyclized polymers obtained from them are also not fully satisfactory in terms of adhesion and compatibility with resins. . In order to easily produce a cyclized polymer with excellent adhesiveness and compatibility with resins, the inventors of the present invention have conducted extensive studies and found that they have achieved an iodine value of 100 to 300 by cyclizing a low molecular weight diene polymer. When producing a cyclized polymer, cis-1,4 is used as a low molecular weight diene polymer.
Molecular weight with binding amount of 70% or more is 10,000 or more
By using a modified low-molecular-weight isoprene-based rubber in which 0.3 to 12 mol% of maleic anhydride or a derivative thereof is added to a low-molecular-weight isoprene-based polymer with a molecular weight of 150,000 yen, the cyclized polymer is We have discovered that it is possible to obtain a cyclized polymer that has excellent adhesive properties and compatibility with resins, and is therefore suitable for printing inks, paints, coating materials, etc., without sacrificing any of its inherent excellent properties. , we have completed the present invention. In the production method of the present invention, the first important thing is to use a low molecular weight isoprene polymer that is the base of the modified polymer to be cyclized and has a specific microstructure and molecular weight.
That is, the low molecular weight isoprene polymer needs to have a cis-1,4 bond content of 70% or more and a molecular weight of 10,000 to 150,000. If the amount of cis-1,4 bonds is too small than the above range, the physical properties of the final cyclized polymer when made into a film will be poor, and for example, when used as a paint or printing ink, the coating properties will be poor. The film becomes brittle and cannot be put to practical use. Therefore, from this point of view, preferably cis-1,4
A binding amount of 80% or more is desirable. Furthermore, this system
The amount of 1,4 bond is determined by infrared absorption spectroscopy. Furthermore, if the molecular weight is less than 10,000, the obtained cyclized polymer will have poor film properties, and when used as a paint, the coating film will easily deteriorate and become brittle. On the other hand, if the molecular weight exceeds 150,000, the solution viscosity becomes too high when the resulting cyclized polymer is used after being dissolved in a solvent, resulting in extremely poor workability. From this point of view, a more desirable molecular weight is about 20,000 to 80,000. In addition,
In the present invention, the molecular weight refers to the viscosity average molecular weight (Mv).
It is calculated from the following formula using the intrinsic viscosity ([η]) measured in a toluene solution at 30°C. [η] = 1.21×10 ^-4 Mv ^0.77 Examples of low molecular weight isoprene polymers having such a specific microstructure and molecular weight include low molecular weight isoprene polymers obtained by anionic polymerization, natural rubber ( Examples include oxidation-degraded low-molecular-weight isoprene rubber obtained by thermal decomposition of solid rubber such as high-molecular-weight synthetic isoprene rubber (IR) produced using NR), Ziegler catalysts, or lithium-based catalysts. . However, low molecular weight isoprene polymers obtained by oxidative reduction molding are unstable in quality and contain many impurities, so low molecular weight isoprene polymers obtained by anionic polymerization are preferred. The low molecular weight isoprene rubber produced by the above-mentioned anionic polymerization method is produced by combining isoprene monomer or isoprene monomer with a small amount of a monomer copolymerizable with isoprene such as butadiene or styrene in the presence of a polymerization solvent. It can be obtained by polymerization using a lithium-based polymerization catalyst in the presence or absence of a lithium-based polymerization catalyst. Typical examples of lithium-based polymerization catalysts include:
Metallic lithium, or organic lithium such as methyllithium, propyllithium, butyllithium, α-naphthyllithium, methylene dilithium, or distyrenyl lithium, and the like can be mentioned. As is well known, the molecular weight of the low molecular weight isoprene polymer is easily controlled by adjusting the ratio of isoprene monomer to catalyst. Additionally, polymerization catalysts are easier to control and are more appropriate to use; examples include inert hydrocarbons such as n-butane, isopentane, n-hexane, n-heptane, benzene, or xylene. However, if a polar hydrocarbon compound is present in the polymerization system, the amount of cis-1,4 bonds in the resulting polymer will often be small, so care must be taken when using it. Such low molecular weight isoprene-based polymers with specific microstructures and molecular weights include maleic anhydride, maleic acid, maleic acid esters,
By adding a maleic anhydride derivative such as maleinamide or maleimide, it is made into a modified low molecular weight isoprene-based polymer, which is used as a starting material for a cyclized polymer. The addition reaction of maleic anhydride or its derivatives to a low molecular weight isoprene polymer can be carried out, for example, by adding maleic anhydride or its derivative to a low molecular weight isoprene polymer in the presence or absence of a solvent or a radical catalyst. This can be easily carried out by heating the reaction. Examples of the solvent used here include n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene, xylene, and halogenated hydrocarbons, which are halogenated products thereof. The modified low molecular weight isoprene polymer used in the present invention includes:
In addition to the above-mentioned modified low-molecular-weight isoprene-based polymer, maleic anhydride groups etc. added to the low-molecular-weight isoprene-based polymer are added in the presence or absence of a catalyst such as p-toluenesulfonic acid. Alcohols such as methanol, ethanol, and propanol are reacted to form one or both of the carboxyl groups based on maleic anhydride, etc., and ammonia, propylamine,
Amidation by reacting a primary monoamine such as butylamine, imidation by dehydration of this amidide, amidation by reaction with an amino alcohol such as ethanolamine or isopropanolamine, and further dehydration. By reacting with primary and tertiary diamines to amidate and dehydrating, N-(aminohydrocarbyl)-maleimide can be added. It also includes things. The reaction to obtain such a derivative is carried out after maleic anhydride is added to the low molecular weight isoprene-based polymer. Among these modified low-molecular-weight isoprene-based polymers, maleic anhydride of the modified low-molecular-weight isoprene-based polymer is preferred over modified isoprene-based polymers to which maleic anhydride is added in terms of its own long-term viscosity stability. Modified low molecular weight isoprene polymers in which acid groups are in the form of alcohol derivatives, amine derivatives, or imide derivatives are preferred. In this way, the modified low molecular weight isoprene polymer, which is the starting material for the cyclized polymer in the production method of the present invention, is manufactured.What is important here is that the modified low molecular weight isoprene polymer is added to the low molecular weight isoprene polymer. The amount of maleic anhydride or its derivative (hereinafter referred to as the added amount) must be 0.3 to 12 mol % based on the isoprene monomer unit of the polymer. In other words, if the amount added is too low, the final cyclized polymer obtained will have a poor effect on improving adhesion and compatibility with the resin, and conversely, if the amount added is too large, the viscosity will decrease when it is made into a solution. becomes too high, resulting in extremely poor workability and making it impossible to achieve the intended purpose. From this point of view, a more preferable addition amount is 1 to 6 mol%. As a method for cyclizing the modified low molecular weight isoprene polymer, a conventionally known method can be used. For example, after dissolving a modified low molecular weight isoprene polymer in an aromatic hydrocarbon solvent such as benzene, toluene, or xylene,
Organic sulfonic acids such as toluenesulfonic acid, Friedel-Crafts catalysts such as tin tetrachloride and titanium tetrachloride, hydrogen halides such as hydrogen chloride and hydrogen bromide,
It can be obtained by adding and heating a nonmetal halide such as boron trichloride, or a phosphorus compound such as phosphorus pentoxide or phosphorine trichloride compound. It can also be obtained by dispersing the modified low molecular weight isoprene rubber polymer in water in the presence or absence of a surfactant to form an aqueous dispersion, then adding the above-mentioned catalyst and causing a heating reaction. . It can also be obtained by directly heating and mixing with a catalyst using a roll or the like. In such a cyclization reaction, natural rubber (NR) or synthetic isoprene rubber (IR) may be mixed and used to the extent that the gist of the present invention is not impaired. When the reaction is carried out in a solution, the concentration of the modified low molecular weight isoprene rubber polymer can be about 5 to 80%. Regardless of which method is used, the reaction should be carried out at room temperature to 200°C.
It is preferably carried out at a temperature of 80 to 150°C for 2 to 10 hours. The cyclization reaction is performed when the iodine value of the cyclized polymer is 100 to 300.
The reaction temperature, reaction time, and concentration of the reaction system are determined so that When the iodine value is less than 100, the resulting cyclized polymer becomes brittle and cannot be applied to applications such as paints and printing inks. Moreover, if the iodine value is greater than 300, the resulting cyclized polymer will have insufficient adhesion and adhesion, which is not preferable. From this point of view, a more preferable iodine value is in the range of 170 to 280. The cyclized polymer obtained by the method of the present invention is
It goes without saying that it has the inherent characteristics such as abrasion resistance and chemical resistance, but also has improved adhesion, adhesion to polyolefins, etc., and compatibility with polar resins such as alkyd resins. It is characterized by its solubility. Such cyclized polymers can be used as printing inks, coating agents for polyolefins, waterproof and corrosion-resistant paints, coating agents, waterproof infiltration agents for concrete, chemical-resistant coating agents, electrical coatings, etc. by adding various compounding agents as necessary. It is preferably used as an insulating material, an adhesive between rubber and metal, a photosensitive resin material such as a photoresist, or a compounding agent for improving the hardness, modulus, etc. of rubber. Furthermore, natural rubber (NR)
It is used as a compounding agent to improve the adhesion, compatibility, etc. of cyclized polymers (cyclized rubber) obtained from synthetic isoprene rubber (IR), etc. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 Isoprene monomer was charged into a pressure-resistant polymerization container using n-heptane as a solvent, then n-butyllithium was added as a catalyst, and the mixture was heated at 60°C in the presence of an inert gas.
Polymerization was performed for 5 hours, and after the polymerization was completed, the polymerization solution was washed with water.
A viscous liquid low molecular weight isoprene polymer was obtained by drying under reduced pressure. The polymer was determined to be cis-1,4 by infrared absorption spectroscopy and viscosity method.
When evaluating the bond amount and viscosity average molecular weight,
The amount of cis-1,4 bonds was 83%, and the viscosity average molecular weight was 31,000. After dissolving this low molecular weight isoprene polymer (abbreviated as PIP in Table 1) in toluene, maleic anhydride (abbreviated as MAn in Table 1) was added from 0.4 to 100 parts by weight of the polymer. 20
A modified low molecular weight isoprene polymer in which maleic anhydride was added in an amount of 0.27 to 13.2 mol % based on the isoprene monomer of the low molecular weight isoprene polymer was obtained by adding parts by weight and stirring in an atmosphere at 180°C. 100 parts by weight of the modified low molecular weight isoprene polymer was dissolved in 100 parts by weight of toluene, and p-
5 parts by weight of toluenesulfonic acid was added and stirred at a temperature of 100°C to carry out a cyclization reaction. After the reaction was completed, the mixture was cooled and 4 parts by weight of aqueous ammonia (25% concentration) was added to terminate the reaction.The reaction solution was then washed with water, poured into methanol, and the cyclized polymer was separated and dried. The obtained cyclized polymer is a yellowish brown solid,
The iodine value evaluated by the Wijs method was as shown in Table 1. In addition, when the cyclization reaction was carried out using an unmodified low molecular weight isoprene polymer instead of the modified low molecular weight isoprene polymer, the iodine value was
209, a yellow-brown cyclized polymer was obtained. 20 parts by weight of the cyclized polymers thus obtained were each dissolved in 100 parts by weight of toluene, and 20 parts by weight of titanium oxide was added thereto to prepare a so-called ink formulation. This formulation was coated onto a low density polyethylene film using a 0.2 mm bar coater and dried overnight at room temperature. Next, cellophane tape was applied to the resulting coating film, and then cellophane tape was peeled off, and a cellophane peel test was conducted to determine whether or not peeling of the coating film by cellophane tape was observed. Adhesion was evaluated. The results are shown in Table 1. Regarding the results, "excellent" means that no peeling is observed at all, "fair" means that peeling is observed in only a small part of the test once every ten times, and "fair" means that peeling is observed only in a small area every time. Cases in which this is acceptable are indicated as "not possible." Similarly, the polyethylene film coated with the ink formulation was rubbed by hand over 20 times, and changes in the state of the coating film surface were observed (hereinafter referred to as the rubbing resistance test). The crack formation status was evaluated. The results are shown in Table 1. The results were graded as "excellent" if no cracks were observed, "fair" if cracks were occasionally observed, and "poor" if many cracks were observed. In addition, 10 parts by weight of cyclized polymer and alkyd resin (manufactured by Hitachi Chemical Co., Ltd., trade name Phthalkyd 355)
-50) Dissolve 10 parts by weight in 100 parts by weight of toluene,
The solution was cast onto glass slides and then dried. The state of the obtained film was observed and the compatibility of the cyclized polymer with the alkyd resin was investigated (hereinafter referred to as
This is called a compatibility test. ). The results are shown in Table 1. The result is "excellent" if a uniform and transparent film is formed, "fair" if a transparent film is formed although it is not sufficient, and "fair" if the film is opaque and has phase separation. In the case where a film was formed in which oxidation was observed, it was indicated as "unacceptable".
Note that when modified low molecular weight isoprene polymers to which 11.9 mol % and 12.5 mol % of maleic anhydride were added were used, the dissolution workability was extremely poor.

[Table] Means a modified low polymer to which maleic acid has been added.
MAn: means maleic anhydride.
Example 2 A modified low molecular weight isoprene polymer with an added amount of maleic anhydride of 1.3 mol % was obtained in the same manner as in Example 1, except that the added amount of maleic anhydride was 2 parts by weight. 100 parts by weight of this modified low molecular weight isoprene polymer was dissolved in 50 parts by weight of toluene, 5 parts by weight of concentrated sulfuric acid (98%) and 5 parts by weight of titanium tetrachloride were added as catalysts, and the mixture was stirred at a temperature of 100°C. A chemical reaction was carried out. After the reaction was completed, the cyclized polymer was separated and dried in the same manner as in Example 1. The obtained cyclized polymer is a yellowish brown solid,
Its iodine value was 201. This cyclized polymer was subjected to a cellophane tape peeling test, a kneading resistance test, and a compatibility test in the same manner as in Example 1 to examine its performance such as adhesiveness and compatibility. The results are shown in Table 2, and the cyclized polymer showed excellent performance in all tests. Example 3 In Example 1, by changing the amount of n-butyllithium used, the amount of cis-1,4 bonds was increased to 85
% and a viscosity average molecular weight of 58000 was obtained. The polymer was reacted with maleic anhydride in the same manner as in Example 1 to produce a maleic anhydride-modified low molecular weight isoprene polymer with an added amount of maleic anhydride of 2.4 mol%, and then methanol was added at a temperature of 70°C. A modified low molecular weight isoprene polymer to which monomethyl maleate was added was obtained. 100 parts by weight of this modified polymer was dissolved in 100 parts by weight of toluene, and 10 parts by weight of p-toluenesulfonic acid was used as a catalyst.
After adding 10 parts by weight and carrying out the reaction with stirring while maintaining the temperature at 100°C, the reaction was stopped by adding 10 parts by weight of aqueous ammonia, and after washing the reaction solution with water, it was poured into methanol and cyclized. The polymer was fractionated and then dried. The cyclized polymer thus obtained was a yellow solid with an iodine value of 238. This cyclized polymer was subjected to a cellophane tape peeling test, a kneading resistance test, and a compatibility test in the same manner as in Example 1 to examine its performance. The results are shown in Table 2, and the cyclized polymer had excellent adhesiveness and compatibility. Example 4 Dimethylaminopropylamine was added to the modified low molecular weight isoprene polymer to which maleic anhydride used in Experiment No. 4 of Example 1 was added, the added maleic anhydride groups were semi-amidated, and the semi-amide By heating the compound at 150°C, a modified low molecular weight isoprene polymer to which N-(dimethylaminopropyl)-maleimide was added was obtained. Using the modified polymer, a cyclization reaction was carried out in the same manner as in Example 1, resulting in a yellowish brown color with an iodine value of 227.
A cyclized polymer was obtained. This cyclized polymer was subjected to a cellophane tape peeling test, a kneading resistance test, and a compatibility test in the same manner as in Example 1 to examine its performance. The results are shown in Table 2, and the cyclized polymer had excellent adhesiveness and compatibility.

[Table] As is clear from Table 2, the cyclized polymers obtained in Examples 2 to 4 all exhibit excellent adhesion and compatibility with the resin.

Claims (1)

[Claims] 1 When cyclizing a low molecular weight diene polymer, the amount of cis-1,4 bonds is 70% as a low molecular weight diene polymer.
In the above, maleic anhydride or a derivative thereof is added to a low molecular weight isoprene polymer having a molecular weight of 10,000 to 150,000 in an amount of 0.3 per isoprene monomer unit of the polymer.
A method for producing a cyclized polymer, characterized by using a modified polymer added with ~12 mol%.