JPH0535722B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing a modified copolymer containing ethylene as a main component and a monomer having a polar group. More specifically, vulcanization is not only vulcanizable with ordinary sulfur or sulfur donors, but also has excellent physical properties such as heat resistance, solvent resistance, weather resistance, ultraviolet resistance, ozone resistance, and low-temperature properties. The present invention relates to a method for producing a modified ethylene copolymer that can give a product (rubber). Prior Art Ethylene-acrylic acid ester copolymer rubber has been proposed as a rubber with excellent properties such as heat resistance and weather resistance.
111814). However, since this rubber has carboxyl groups as crosslinking sites, amine crosslinking and ionic crosslinking are possible, but the compounding technology has been established in the rubber industry and the equipment is relatively simple. The widely practiced so-called sulfur vulcanization with sulfur or sulfur donors is therefore not possible. In the case of amine crosslinking, it is not only problematic to select the type of amine and other formulation agents (e.g. crosslinking accelerator) and to determine the mixing and crosslinking conditions in order to obtain a suitable crosslinked product; There are also problems with the facilities.
The same holds true for ionic crosslinking. In addition, in the case of amine crosslinking, the uncrosslinked rubber mixture in which di(poly)amine is kneaded into the rubber for crosslinking tends to react even at room temperature, and therefore does not have good storage stability. It also tends to cause scorch during the crosslinking operation. Problems to be Solved by the Invention In view of the above, the present invention does not have these problems and not only enables vulcanization with sulfur or a sulfur donor, but also enables vulcanization of the ethylene-acrylic ester by an amine crosslinking method. The object of the present invention is to provide a method for producing a modified ethylene copolymer that can provide a vulcanizate (rubber) having heat resistance, weather resistance, low-temperature properties, and vibration resistance equivalent to or better than polymerized rubber. Means for Solving the Problems According to the present invention, these problems are solved by combining ethylene, alkyl (meth)acrylate and maleic anhydride in the presence of a free radical polymerization initiator and using an organic solvent at a temperature of 50 to 200°C. ,5~200Kg/ ^cm2
conditions, and 120-260℃, 500-2500℃ without solvent.
Copolymerization under conditions selected from the group consisting of Kg/ ^cm2 , and further hydrolyzing and half-esterifying at least a portion of maleic anhydride using water and saturated alcohol. It has been found that the problem can be solved by adopting a method for producing a modified ethylene copolymer, in which the resulting ethylene copolymer is reacted with an unsaturated amine and/or an unsaturated alcohol. The contents of the present invention will be explained in detail below. Ethylene, alkyl (meth)acrylate and maleic anhydride are 70-84 mol% and 15-27 mol%, respectively.
It is preferable to polymerize in the range of mol% and 1 to 3 mol%, and the respective components constituting the resulting copolymer are 50 to 94.9 mol%, 5 to 45 mol%, and 0.1 to 5.0 mol%. . An organic peroxide (for example,
Free radical polymerization initiators such as benzoyl peroxide, tertiary-butyl peroxide, 2,5-dimethyl-di-tertiary-butyl peroxide) and azobis compounds (eg, azobisisobutylnitrile) are used. In addition, when using an organic solvent, toluene, hexane, etc. are suitable, and the polymerization temperature is 50~
The conditions selected are 200°C and a polymerization pressure of 5 to 200 kg/cm ² . On the other hand, the above copolymerization reaction is also possible without a solvent, and in this case, the polymerization temperature is 120 to 260°C,
As the polymerization pressure, conditions of 500 to 2500 kg/cm ² are selected. The alkyl (meth)acrylate used in the present invention is a compound represented by the following general formula. (In the formula, R ¹ is a hydrogen atom or a methyl group,
(R ² is a linear or branched alkyl group having 1 to 10 carbon atoms) Representative examples of R ² in the above formula include a methyl group,
Examples include ethyl group, butyl group and 2-ethylhexyl group. Typical examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid-n.
-butyl, tertiary-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate. The copolymerization ratio of units derived from alkyl (meth)acrylate in this copolymer is 5% by weight.
If it is less than this, the rubber elasticity of the modified ethylene copolymer obtained will be lost and permanent elongation and compression set will become large, which is not preferable. On the other hand, if it exceeds 45 mol%, the low-temperature brittleness of the resulting modified ethylene copolymer deteriorates, which is undesirable. At least a portion of the maleic anhydride used in the present invention is half-esterified after hydrolysis as described below, but if the total copolymerization ratio of both is less than 0.1 mol%, the maleic anhydride groups in the copolymer A modified ethylene copolymer having the desired rubber elasticity and heat resistance cannot be obtained even by bonding a compound having an unsaturated group to all of the dicarboxylic acid and/or half ester groups described below and vulcanizing it with sufficient sulfur. Can not. On the other hand, if it exceeds 5.0 mol%,
Not only does this impair the flexibility of the resulting modified ethylene copolymer, but it is also unfavorable for obtaining the desired rubber properties. The maleic anhydride is at least partially hydrolyzed with water and half-esterified using a saturated alcohol. The specific method will be described. When an organic solvent is used in the copolymerization reaction, the ethylene copolymer is mixed with a catalyst (e.g., toluene) in an organic solvent that dissolves the copolymer (e.g., toluene).
tertiary amine) at a temperature of 80 to 100°C for 0.5 to 10 hours (preferably 2 to 6 hours, suitably 3 to 6 hours), followed by neutralization with acid. You can get it. Moreover, half-esterification can be obtained by using the solution method or kneading method described below for the ethylene copolymer. As in the case of hydrolysis, the solution method is carried out in an organic solvent in the presence or absence of the above-mentioned catalyst (the reaction is slow in its absence) at the reflux temperature of the alcohol used for 2 minutes to 5 hours (preferably 2 hours). This is a method of reacting for 15 minutes to 2 hours, preferably 15 minutes to 1 hour). On the other hand, the kneading method is usually 0.01 to 1.0 parts by weight (preferably,
Generally 0.1 to 3.0 times the mole (preferably,
Kneading 1.0 to 2.0 times the mole of saturated alcohol at a temperature above the melting point of the ethylene copolymer but below the boiling point of the alcohol used, using a Banbury mixer, extruder, etc., which are commonly used in the fields of rubber and synthetic resins. This is a method in which the reaction is carried out while kneading using a machine for several minutes to tens of minutes (preferably 10 to 30 minutes). The saturated alcohol used in the above half-esterification is a linear or branched saturated alcohol having 1 to 12 carbon atoms, and includes methyl alcohol, ethyl alcohol, and primary butyl alcohol. In the case of the above hydrolysis and in the case of the half esterification reaction, the conversion rate to dicarboxylic acid and the half esterification rate are both 0.5 to 100%, preferably 1 to 100%, and 10 to 100%. suitable. As mentioned above, in addition to ethylene and alkyl (meth)acrylate, an ethylene copolymer consisting of a monomer in which at least a portion of maleic anhydride is half-esterified can be produced by modifying it with an unsaturated amine or an unsaturated alcohol. The modified ethylene copolymer of the present invention can be produced. The unsaturated amines used have at least one double bond, and primary or secondary amines are preferably used. That is, its general formula is shown by the following formula. In the formula, R ³ and R ⁴ are hydrogen atoms or hydrocarbon groups having at least one double bond,
At the same time, it cannot be a hydrogen atom. In the above general formula, those having at most 30 carbon atoms are preferred, and those with 2 to 20 carbon atoms are particularly preferred. Further, it is desirable that the material be liquid or solid at room temperature to the reaction temperature described below. Representative examples of the unsaturated amine include 1-amino-9-octadecene, 1-amino-7-hexadecene, 1-amino-5-pentadecene, 1-amino-4-tetradecene, 1-amino-4-tridecene, 1-amino-3-dodecene, 1-amino-
2-decene, 1-amino-2-octene and 1
-amino-2-hexene. Further, the unsaturated alcohol used in the present invention has at least one double bond, and is preferably liquid or solid at room temperature to the reaction temperature described below. Further, it is desirable that the number of carbon atoms is at most 30, and preferably 2 to 25 carbon atoms. Furthermore, aliphatic or aromatic compounds having one hydroxy group are preferred. Representative examples of the unsaturated alcohol include 1-hydroxy-9-octadecene, 1-hydroxy-9-octadecene, and 1-hydroxy-9-octadecene.
unsaturated aliphatic alcohols such as 7-heptadecene, 1-hydroxy-5-tetradecene, 1-hydroxy-5-dodecene, 1-hydroxy-3-octene and allyl alcohol, as well as paravinylphenol, vinylhydroxybiphenyl and vinylnaphthol. Examples include unsaturated aromatic alcohols (or phenols). The usage ratio of the unsaturated amine and/or unsaturated alcohol to the maleic anhydride or its derivative is 0.2 to 2.0 times, and 0.2 to 1.5
The amount is preferably twice the molar amount, and preferably 0.2 to 1.0 times the molar amount. If the amount is less than 0.2 times the mole, a modified ethylene copolymer having the desired modification effect cannot be obtained. On the other hand, if it exceeds 2.0 times the mole, unreacted unsaturated amines and unsaturated alcohols will remain in the modified ethylene copolymer, causing odor and bleeding, and the desired physical properties will not be obtained. unfavorable to The modified ethylene copolymer of the present invention is produced, for example, as follows. That is, as mentioned above, an ethylene copolymer having a specific structure and an unsaturated amine and/or
Or, by dissolving the unsaturated alcohol in a solvent or without dissolving it in a solvent, using a kneader such as a Banbury or a vented single-screw or twin-screw extruder, the temperature is above the melting point of the ethylene copolymer.
3 at a temperature that does not cause thermal decomposition (i.e. 120-300℃)
It is obtained by kneading for ~20 minutes (preferably 3 to 15 minutes). In addition, when modifying with an unsaturated alcohol, a small amount of catalyst (for example, a tertiary amine if the copolymer contains an acid anhydride mainly as a monomer unit), In the case of mainly containing a dicarboxylic acid or a half ester, it is desirable to add an acid catalyst such as P-toluenesulfonic acid. The MI of the modified ethylene copolymer obtained as described above is usually 0.01 to 1000 g/10 minutes, and the MI
is less than 0.01g/10 minutes, various additives listed below,
When blended with sulfur, a sulfur donor, a vulcanization accelerator, etc., it not only has poor kneading properties but also poor moldability. Kneading is achieved by mixing at a temperature of 30°C or higher, as in the case of commonly used rubbers. A vulcanized product can be obtained by molding this mixture into a sheet or any desired shape using a roll, calendar roll, or extruder and subjecting it to steam vulcanization or press vulcanization. The vulcanizate obtained by vulcanization as described above is extremely rich in rubber elasticity, and has a permanent elongation rate of 45% or less at room temperature (20°C).
It also has excellent weather resistance, and even after being left at a temperature of 190°C for more than 70 hours, the elongation remaining at break remains more than 50%. EXAMPLES AND COMPARATIVE EXAMPLES The present invention will now be explained in more detail with reference to Examples. In the Examples and Comparative Examples, the reaction rate of unsaturated amine or unsaturated alcohol was determined by extracting the modified ethylene copolymer using a Soxhlet without a solvent, and measuring the unreacted amount in the extract by gas chromatographic analysis. It was calculated by quantifying the
Similarly, the modified ethylene copolymer was extracted with a non-solvent [a mixture of carbon tetrachloride and methyl alcohol (volume ratio 6:4)] using a Soxhlet,
The reaction rate was calculated by determining the iodine value of unreacted unsaturated amine or unsaturated alcohol in the extract. Furthermore, the tensile test was measured according to JIS K-6301. In addition, the Shore hardness (A) is
It was measured according to JIS K-6301. Furthermore, the heat resistance test was performed by leaving the sample at a temperature of 190° C. for 79 hours, and measuring the elongation rate according to JIS K-6301. Moreover, the permanent elongation rate was measured according to JIS K-6301. Furthermore, the content of maleic anhydride was determined by nuclear magnetic resonance and infrared absorption spectroscopy. Examples 1 and 2 Terpolymer consisting of 80 mol% ethylene, 18.5 mol% methyl acrylate and 1.5 mol% maleic anhydride [MI220g/10 min, hereinafter referred to as "copolymer (1)"] 20g was dissolved in 220ml toluene. To this solution were added 100 ml of water and triethylamine in an amount 3 times the mole percent of the maleic anhydride portion of the copolymer, and heated (hydrolyzed) at a temperature of 80° C. for 5 hours with stirring. Thereafter, hydrochloric acid was added to neutralize it, and further hydrochloric acid was added until it became weakly acidic, and then it was left to stand for a day and night. Then, hexane was added as a precipitation solvent to precipitate the polymer, and the hexane was exchanged several times to wash the polymer. Thereafter, the polymer was air-dried at 40°C all day and night. The hydrolysis rate was calculated from the decrease in absorption due to acid anhydride at 1760 cm ^-1 by infrared absorption spectrum measurement (the same applies hereinafter). Hydrolysis rate is 100
It was %. Oleylamine was added in an amount of 0.5 times the mole of dicarboxylic acid groups in the hydrolyzate of copolymer (1) obtained as above, and 120
respectively under conditions of 40 revolutions/min at a temperature of °C.
The reaction was carried out while kneading for 20 minutes. As a result, 84% of the theoretical value of oleylamine was reacted (Example 1). Further, the conditions were the same as in Example 1, except that oleyl alcohol was used in an amount of 1.0 times the mole of dicarboxylic acid groups in the hydrolyzate of copolymer (1) in place of the oleylamine used in Example 1. The reaction was carried out while kneading. As a result, the theoretical value
76% of the oleyl alcohol had reacted (Example 2). Examples 3 and 4 Terpolymer consisting of 72.2 mol% ethylene, 26.8 mol% methyl acrylate and 1.0 mol% maleic anhydride [MI 9.1 g/10 min, hereinafter referred to as "copolymer (2)"] 20g of the product was dissolved in 220ml of toluene, 100ml of methyl alcohol and 1ml of triethylamine were added, and the reaction was carried out for 6 hours under refluxing conditions of methyl alcohol. Then, washing and drying were performed in the same manner as in the hydrolysis of the ethylene copolymer (1). As above, from the measurement of infrared absorption spectrum analysis, the half esterification rate is
It was 60%. The half-esterified product of copolymer (2) thus obtained was modified using oleylamine (Example 3) or oleyl alcohol (Example 4) in the same manner as in Example 1 or Example 2. Summer. The reaction rates were 85% and 78%, respectively. Examples 5 and 6 Terpolymer consisting of 83 mol% ethylene, 15.5 mol% ethyl acrylate and 1.5 mol% maleic anhydride [MI212 g/10 min, hereinafter referred to as "copolymer (3)"] was half-esterified, washed and dried under the same conditions as for copolymer (2). As a result, copolymer (3) was found to be 80% half-esterified. The half-esterified product of copolymer (3) obtained as above was modified using oleylamine (Example 5) and oleyl alcohol (Example 6) in the same manner as in Example 1 or Example 2. I did this. The reaction rates were 87% and 72%, respectively. In place of the copolymer (1) used in Example 1, a copolymer of methyl methacrylate containing 90 mol% ethylene and 10 mol% ethylene (MI250g/10
The reaction was carried out by adding oleylamine in the same manner as in Example 1 (this copolymer does not have a maleic anhydride group, so it does not undergo a hydrolysis reaction, and of course it does not react with oleylamine. ) (Comparative Example 1). In place of the copolymer (2) used in Example 3, a copolymer consisting of 74 mol% ethylene and 26 mol% methyl methacrylate (MI9.4g/10
The reaction was carried out by adding oleylamine in the same manner as in Example 3, except that oleylamine was used (no hydrolysis reaction was performed for the same reason as Comparative Example 1. Of course, it did not react with oleylamine either) (Comparative Example 2). In place of the copolymer (1) used in Example 1, a copolymer (MI 300 g/10 min) consisting of 79 mol% ethylene, 11 mol% methyl methacrylate and 10 mol% maleic anhydride was used. Hydrolysis, neutralization, washing and drying were otherwise carried out in the same manner as in Example 1. The hydrolysis rate was 100%.
Oleylamine was added to the obtained hydrolyzate under the same conditions as in Example 1, and the reaction was carried out. As a result, 80% of the theoretical oleylamine was reacted (Comparative Example 3). Instead of the copolymer (1) used in Example 1, a copolymer (MI 6.7 g/10 min) consisting of 96.7 mol% ethylene, 1.0 mol% methyl methacrylate and 2.3 mol% maleic anhydride was used. Except for the use, hydrolysis, neutralization, washing and drying were carried out in the same manner as in Example 1. The hydrolysis rate was 100%. Oleylamine was added to the obtained hydrolyzate under the same conditions as in Example 1, and the reaction was carried out. As a result, 80% of the theoretical oleylamine was reacted (Comparative Example 4). [Physical property evaluation] Sulfur powder (200 mesh pass, hereinafter referred to as "S"), the mixing ratio of which is shown in Table 1, was added to 100 parts by weight of the modified ethylene copolymer obtained as described above. Tetramethylthiuram disulfide (hereinafter referred to as "TT") as a glidant, 2-mercaptobenzothiazole (hereinafter referred to as "M"), and dipentamethylenethiuram tetrasulfide (hereinafter referred to as "M") as a sulfur donor. TRA”
), zinc oxide as a galvanic accelerator, stearic acid as a vulcanization accelerator and tetrakis [methylene-3,5-di-tert-butyl-4-hydroxy-hydrocinna] as an anti-aging agent. [Mate]methane (hereinafter referred to as "1010") was blended and kneaded with two rolls at room temperature. Each mixture obtained was heated to 60Kg/cm ² at 150℃.
Vulcanization was carried out while pressing for 40 minutes under a pressure of . Tensile test and Shore hardness of the obtained vulcanizate
(A) Permanent elongation and heat resistance tests were conducted. The results are shown in Table 2. In addition, when measuring the permanent elongation rate of the test piece obtained in Comparative Example 1, the elongation did not return to its original state. Further, when the aging test was conducted on each sample obtained in Comparative Example 1 and Comparative Example 2, the specimens were in a molten state.

【table】

[Table] Effects of the Invention A modified ethylene copolymer is obtained by the production method according to the present invention, which can be cured by sulfur vulcanization (not to mention crosslinking with organic peroxides), which is widely practiced in the general rubber industry. possible) is possible.
Furthermore, the obtained vulcanizate also exhibits the following effects. (1) Good heat resistance. (2) Excellent solvent resistance, weather resistance, UV resistance, and ozone resistance. (3) Good low temperature characteristics. (4) Rubber properties (e.g. tensile strength, elongation)
and has excellent hardness.

Claims (1)

[Claims] 1. Ethylene, alkyl (meth)acrylate and maleic anhydride in the presence of a free radical polymerization initiator and using an organic solvent, 50 to 200°C, 5
~200Kg/ ^cm2 condition and 120~260℃ without solvent,
Copolymerization is carried out under conditions selected from the group consisting of 500 to 2500 Kg/cm ² , and this copolymer is further hydrolyzed and half-esterified to remove at least a portion of maleic anhydride using water and saturated alcohol. A method for producing a modified ethylene copolymer, which comprises reacting an ethylene copolymer obtained by a chemical reaction with an unsaturated amine and/or an unsaturated alcohol. 2 70-84 mol% ethylene, alkyl (meth)
Using 15 to 27 mol% of acrylate and 1 to 3 mol% of maleic anhydride, the unit from which ethylene is derived is
50.0 to 94.9 mol%, 5 to 45 mol% of units derived from alkyl (meth)acrylate, and 0.1 mol% of units derived from maleic anhydride and its half ester.
2. The method for producing a modified ethylene copolymer according to claim 1, wherein the content is 5.0 mol%.