JPH0323571B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing polyamide. Specifically, the present invention relates to a polyamide manufacturing method in which polymerization is performed while defoaming foam generated in a foam generation process to shorten polymerization time. [Prior Art] In the production of polyamide, regardless of the polymerization method (batch method or continuous method), in many manufacturing methods, foaming is the rate-limiting step in the step where foam is generated, and improvements in this respect are still desired. was. [Purpose of the Invention] As a result of extensive research into defoaming in the process of foam generation during polyamide production, the present inventors have developed a method for polymerizing polyamide raw materials in the presence of a specific amount of a specific hydrocarbon polymer. At that time, he learned that the foam generation process had an excellent defoaming effect, and completed a method for producing polyamide that had great industrial value. That is, the present invention focuses on the presence of a hydrocarbon polymer (hereinafter referred to as a modified hydrocarbon polymer) having a number average molecular weight of 500 to 20,000 and having a carboxylic acid group (carboxyl group), a carboxylic acid derivative group, an amino group, or a hydroxyl group. This is achieved by polymerizing the polyamide raw material underneath. [Structure of the Invention] The polyamide raw material as used in the present invention is a lactam having three or more membered rings, a polymerizable ω-amino acid, or a dibasic acid and a diamine. Specifically, ε-caprolactam, enantholactam, capryllactam, lauryllactam, α-pyrrolidone, α-
lactams such as piperidone, ω-amino acids such as 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, adipic acid, glutaric acid, pimelic acid,
Suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadionic acid, hexadecadionic acid, hexadecenedioic acid, eicosandioic acid, eicosadienedionic acid, diglycolic acid,
Dibasic acids such as 2,2,4-trimethyladipic acid, xylylene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, hexamethylene diamine, tetramethylene diamine, nonamethylene diamine, undecamethylene Diamine, dodecamethylene diamine, 2,
Examples include diamines such as 2,4 (or 2,4,4)-trimethylhexamethylene diamine, bis-(4,4'-aminocyclohexyl)methane, and metaxylylene diamine. The polymerization reaction for producing the polyamide of the present invention may be started using the above-mentioned polyamide raw materials according to a conventional method, and the above-mentioned modified hydrocarbon polymer starts a pressure release or depressurization reaction from the start of the reaction. It can be added at any stage up to. In addition, in the case of polymerizing lactams using an alkali catalyst, alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium, calcium, strontium and barium, or hydrides thereof can be used as catalysts. This reaction may be carried out in the presence or absence of an organic diluent. In this case, the modified hydrocarbon polymer can be added at any stage up to the start of the reaction. The hydrocarbon polymer is preferably a homopolymer of α-olefin such as ethylene or propylene, or a copolymer thereof, or a hydrogenated product of a homopolymer or copolymer of a diene, and a hydrogenated product of a diene polymer is particularly preferred. It is. As the diene polymer, for example, 1,3
- There are homopolymers or copolymers obtained by polymerizing at least one monomer selected from butadiene, 1,3-pentadiene, chloroprene, isoprene, etc. Among them, conjugated diene polymers, particularly polybutadiene and polyisoprene, are preferably used. . There are various methods for polymerizing the diene polymer, such as radical, cation, anion, and coordination anion, and any of these methods may be used. Further, at this time, styrene, α-methylstyrene, o- or p-vinyltoluene, vinylxylene, acrylonitrile, etc. may be coexisting as a comonomer. Methods for introducing hydroxyl groups into hydrocarbon polymers include reacting a living polymer of a diene compound with ethylene oxide, hydrogen peroxide, 4,
Examples include a method of radical polymerization using an -OH group-containing radical initiator such as 4'-azobis (4-cyano-n-amyl alcohol). Furthermore, as hydrocarbon polymers having hydroxyl groups, there are commercially available products such as those listed below, and these can be used as they are. Nisso-PB G-1000 Manufactured by Nippon Soda Co., Ltd. 〃 〃 〃 〃 〃 G-3000 〃 〃 GI-1000 〃 〃 GI-2000 〃 〃 GI-3000 〃 〃 C-1000 〃 〃 GI-1000 〃 Politere H Mitsubishi Manufactured by Kasei Co., Ltd.〃 HA〃 Poly-BD Manufactured by Arco Butarez HT Hycar BTB manufactured by Philips Co., Ltd. Manufactured by Gutsudoritsu Telosen HT Manufactured by General Tire Co., Ltd. (All names are trademarks) Carboxylic acid groups or Methods for introducing carboxylic acid derivative groups such as ester groups, acid halide groups, or amide groups include a method in which a living polymer of a diene compound is reacted with carbon dioxide, and a method in which a living polymer of a diene compound is reacted with carbon dioxide, There is a method of radical polymerization of a diene compound using an initiator having a carboxyl group or a carboxylic acid-derived group such as (eg, methane), and a method of reacting an acid halide or an acid anhydride with the hydrocarbon polymer having a hydroxyl group. . In addition to this, there is also a method in which a monomer having a carboxyl group or a carboxylic acid derivative group is reacted with a diene-containing polymer. Monomers having carboxylic acid groups or carboxylic acid derivative groups include, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, chloromaleic acid,
Examples include itaconic acid or derivatives thereof, such as esters with methanol, phenol, etc., and acid anhydrides such as maleic anhydride. These monomers may be added to the hydride of the diene-containing polymer as a carboxylic acid derivative, or the carboxylic acid group may be converted to the corresponding derivative after addition of the carboxylic acid or its anhydride. Examples of the method for introducing an amino group include a method in which the hydroxyl group of a diene-containing polymer into which a hydroxyl group has been introduced is cyanoethylated and then hydrogenated, or a method in which the hydroxyl group is halogenated and then aminated. The number average molecular weight of these modified hydrocarbon polymers is
It is desirable that the number is 500 to 20,000, preferably 1,000 to 10,000. If the molecular weight is too small, the antifoaming effect will not be exhibited, which is undesirable. On the other hand, if it is too large, dispersion into the polyamide will be poor and the antifoaming effect will not be noticeable. The number average molecular weight ( ) of the hydrocarbon polymer component in the modified hydrocarbon polymer was determined by the terminal group quantitative method. =10 ⁶ /(total number of terminal groups (μeq/g)/2) The total number of terminal groups of the modified hydrocarbon polymer is, for example, in the case of a modified polybutadiene dicarboxylic acid,
The acid value corresponds to the total number of terminal groups. The acid value was determined by dissolving the modified hydrocarbon polymer in a good solvent suitable for the molecular weight and titrating with alkali. The amount of the modified hydrocarbon polymer to be present when polymerizing the polyamide raw material is 1 to 5000 ppm, preferably 2 to 5000 ppm, based on the polyamide raw material.
More preferably, it is 5 to 1000 ppm. If this amount is too small, the defoaming effect will not be obtained. On the other hand, if the amount is too large, foaming will increase more than when nothing is added, which is not preferable. When polymerizing the polyamide raw material of the present invention, in addition to the polyamide copolymer, reinforcing agents such as glass fiber and carbon fiber, fillers such as silica, alumina, silica alumina, silica magnesia, calcium carbonate, gypsum, and clays, Stearic acid, octadecyl stearate, barium stearate,
Lubricants such as higher fatty acids or derivatives thereof such as calcium stearate and magnesium stearate, flame retardants such as melamine derivatives, cyanuric acids and triazinyl base rings, and other well-known additives may be present. [Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. <Production example of a hydrocarbon polymer having a carboxylic acid group> 10 purified cyclohexane (treated with LiAlH ₄ and then distilled with ArF) and 1 kg of butadiene were placed in a 20 reactor, and while stirring, 0.46 mol of n-BuLi was added to hexane. It was added as a solution (2 mol/). After continuing the reaction for 24Hr at room temperature, molecular sieve MS
-4A dehydrated carbon dioxide gas was introduced into the reaction solution. After washing the polymer solution with water to remove the initiator, the solvent was distilled off under reduced pressure to obtain 900 g of polymer. The number average molecular weight by VPO was 2200. The obtained polymer was dissolved in isopropanol/n-heptane (1/1) solvent and Ru/C was used as a catalyst.
Hydrogenation reaction was carried out at 120°C, 30 atm, and 6 hours. The carboxylic acid group of the obtained polymer was 0.45meq/g,
The iodine value was 3.5. Examples 1 to 8 and Comparative Examples 1 to 4 In a 200-inch autoclave, 60 kg of ε-caprolactam, 1.2 kg of water, and the hydrocarbon polymer having a carboxylic acid group produced in the above production example in the amounts shown in Table 1 below were placed. , or number average molecular weight 2000, hydroxyl group
0.9meq/g, a hydrocarbon polymer having hydroxyl groups with an iodine value of 3.5 (manufactured by Mitsubishi Chemical Industries, Ltd., registered trademark, Polytail HA), or this and stearic acid or barium stearate were charged, and the temperature was raised to 260°C. A pressurized reaction was carried out for 2 hours. Next, the pressure was released while keeping the foam volume/liquid volume in the autoclave constant at 0.8, and the time required to reach normal pressure was measured. The results were as shown in Table 1 below. After releasing the pressure, a polymerization reaction was carried out at 250℃ and 500 torr for 2 hours, and after returning to normal pressure, it was extracted as a strand.
Chip formation, extraction and removal of unreacted monomers, and drying were performed. The relative viscosity of the obtained polyamide was as shown in Table 1 below. For comparison, the results obtained when the polyamide copolymer was not added and the other operations were the same as in the examples are also shown. The relative viscosity is a value measured in accordance with JISK6810 at a concentration of 1% in 98% sulfuric acid and a temperature of 25°C.

【table】

〔Effect of the invention〕

According to the present invention, by using a very small amount of modified hydrocarbon polymer, foaming during polyamide production can be significantly reduced, especially when higher fatty acids or their derivatives are added. Even in cases where foaming is likely to occur during polymerization, the antifoaming effect is remarkable and has great industrial value.

Claims (1)

[Scope of Claims] 1 A polyamide raw material is prepared in the presence of a hydrocarbon polymer having a number average molecular weight of 500 to 20,000 and having a carboxyl group, a carboxylic acid derivative group, an amino group, or a hydroxyl group in an amount of 1 to 5000 ppm based on the polyamide raw material. A method for producing polyamide, characterized by polymerization. 2. The method for producing a polyamide according to claim 1, wherein the hydrocarbon polymer is a hydrogenated product of a diene polymer.