JPS62256829A - Production of polyamide molding - Google Patents

Abstract

PURPOSE:To produce a polyamide molding of good mold releasability, by adding a specified fatty acid amide to a lactam and molding the mixture by polymerization in the presence of an alkali catalyst and a promotor. CONSTITUTION:A lactam (e.g., gamma-butyrolactam) is mixed with 0.05-2wt% fatty acid amide of formula I, II or III [wherein R and R' are each an (un)saturated aliphatic group and n is 5-10], 0.05-10mol% alkali catalyst (e.g., sodium lactan), 0.03-10mol% promotor (e.g., N-acyllactam) and, optionally, 2-25wt% plasticizer (e.g., N-alkylpyrrolidone), 2-50wt% filler (e.g., CaCO3) and/or fiber (e.g., milled glass), 1-15wt% blowing agent (e.g., benzene), etc., and the obtained mixture is polymerized and molded by heating for at most 1hr to a temperature of >=the m.p. of the lactam to <=m.p. of the formed polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing polyamide molded articles with good mold releasability using an alkaline polymerization method of lactams.

(Prior Art and its Problems) It is known to simultaneously polymerize and mold lactams using a method of polymerizing lactams under the action of an alkali catalyst and a cocatalyst, a so-called alkaline polymerization method.

In the above method, the mold surface and a part of the molded product surface adhere to each other, so it takes time to take out the molded product, the molding cycle becomes longer, and the smoothness of the molded product surface is impaired. be.

BACKGROUND ART Conventionally, as a method for improving the releasability of a molded article from a mold, a method of applying an external mold release agent such as silicone to the surface of the mold is known. However, this method has the problem that it is necessary to apply an external mold release agent every time molding is performed, and that it is difficult to uniformly apply the mold release agent.

Japanese Patent Publication No. 47-51479 discloses a method for improving the mold releasability of a molded article by adding alkylnaphthalene or methylphenyl polyoloxane to lactams during alkaline polymerization of lactams. There is. Bota, Japanese Patent Publication No. 48-17560, discloses that during alkaline polymerization of lactams, a metal salt of phosphonic acid or an aromatic ether of polyoxyalkylene glycol is added to the lactams to improve the mold releasability of the molded product. Describes how to improve it.

These methods require only the addition of an internal mold release agent to the raw material lactam, so workability is improved compared to methods in which an external mold release agent is applied to the mold. However, the above-mentioned compounds used as internal mold release agents have drawbacks such as a decrease in the polymerization rate of lactams, poor compatibility with lactams, and difficulty in uniformly dispersing them. Although the molded product can be easily removed from the mold, the time it takes for the molded product to be released from the mold surface is not so shortened compared to when no internal mold release agent is used.

(Technical means for solving the problem) The object of the present invention is to solve the problem by using a specific internal mold release agent in the alkaline polymerization of lactams.

Provides a method that easily disperses into lactams without reducing the polymerization rate of lactams, shortens the time it takes for a molded product to be released from a mold, and facilitates removal of the molded product. It's about doing.

The above object is a method for polymerizing lactams by the action of an alkali catalyst and a cocatalyst.

Formula RCONH(CH)nNI(COR(1).

Fatty acids represented by ROOMHR' (If) and RNHCONHR' (III) (wherein R, R' are saturated or unsaturated aliphatic groups having 7 to 30 carbon atoms, and n is an integer of 5 to 1C) One or more types of amides, zero for lactams
, 05 to 2% by weight.

Generally, it is known that compounds having an amide group (-CONH-) reduce the alkaline polymerization rate of lactams, but the aliphatic amide used in the present invention is a special compound that does not have a negative effect on the polymerization reaction. it is conceivable that.

Specific examples of lactams used in the present invention include r-
Butyrolactam, δ-valerolactam.

Examples include ε-caglolactam, ω-enantholactam, ω-capryllactam, ω-undecanolactam and ω-laurinlactam. These lactams may be used alone or in combination of two or more.

As the alkali catalyst, all compounds used in known alkaline polymerization methods of lactams can be used. Specific examples include alkali metals, alkaline earth metals, and hydrides thereof.

Oxides, hydroxides, carbonates, alkylated products or alkoxides, Grignard compounds, sodium naphthalene, and reaction products of the above metals or metal compounds with lactams 1 Examples include sodium lactam, potassium lactam, and lactam magnesium bromide. It will be done. What is the amount of alkaline catalyst used?

0.05 to 10 molar relative to lactams, especially 0.2
It is preferable that it is 5 molar ratio.

As for the co-catalyst, all compounds used in known alkaline polymerization methods for lactams can be used. Specific examples include N-acyllactams, organic incyanates, acid chlorides, acid anhydrides, esters, urea derivatives, carbodiimides and ketenes. 1 more
Polymers having two or more hydroxyl groups, thiol groups, amino groups or carboxyl groups at the molecular terminals, adipoyl biscaprolactam, sebacoyl biscaprolactam, hexamethylene-1,6-biscaprolactam.

Alternatively, a reaction product obtained by reacting diisocyanate in an amount equivalent to or more than the functional group of the polymer can also be used as a cocatalyst. By using these reaction products as co-catalysts, the impact resistance of the resulting polyamide can be greatly improved. The amount of co-catalyst used is preferably 0.03 to 10 mol per lactam.

The fatty acid amide represented by formula (1), (I[) and <m> is an amide of saturated or unsaturated fatty acid, and specific examples of formula (I) include hexamethylenebisoleic acid amide, hexamethylenebisstearin 1 type of acid amide etc. (■)
So, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl palmitic acid amide,
N-oleyl palmitic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide.

N-stearyl stearic acid amide etc. is 1 formula (III)
So, N-butyl-N-stearylurea, N-pubi-N
-suf7') lurea, N-aryl-N-stearylurea, N-phenyl-N-stearylurea.

Examples include N-stearyl-N-stearylurea.

Among these, hexamethylene bis oleic acid amide, N-oleyl stearic acid amide and N-butyl-N
-Stearyl urea is preferred. These fatty acid amides may be used alone.

Two or more types may be used in combination.

The amount of fatty acid amide used is 0.0 compared to lactams.
1-2 weight. If the amount used is less than the lower limit, the effect of improving the mold releasability of the molded article will be poor, and if the amount used is more than the upper limit, the polymerization reaction rate of the lactam will decrease.

Fatty acid amides are usually added to lactams prior to alkaline polymerization of the lactams.

Alkaline polymerization of lactams in the present invention.

It can be carried out according to methods known per se, and the polymerization temperature is set at 6° above the melting point of the lactam to be polymerized and below the melting point of the polyamide produced.

Polymerization time is usually 1 hour or less.

In the present invention, plasticizers, fillers, fiber blowing agents, dyes, and pigments that do not substantially inhibit the polymerization reaction.

Lactams can also be polymerized in the presence of antioxidants and the like. Preferred plasticizers include N-alkylpyrrolidone, dialkylimidazolidinone, etc.
The amount used is usually 2 to 25 parts by weight based on the lactam. Specific examples of fillers include calcium carbonate, wollastonite, kaolin, graphite, 1 stone, 8 feldspar, mica, and asbestos.

Examples include carbon black and molybdenum disulfide. A specific example of fiber is milled glass.

Fibrous magnesium compound, potassium titanate fiber, mineral fiber, graphite fiber, boron fiber.

Examples include steel fiber. The amount of fillers and/or fibers used is usually 2 to 50% by weight, based on the lactams. Specific examples of blowing agents include benzene, toluene,
Examples include xylene, and the amount used is usually 1 to 15 parts by weight relative to the lactams. The present invention produces round rods and plates directly from lactams by casting method or reaction injection molding method.

This method is suitable as a method for manufacturing molded products such as pipes or automobile parts.

(Effects of the Invention) As shown in Examples and Comparative Examples, the present invention shows that when ε-caprolactam is polymerized by adding a specific fatty acid amide, the mold release start time is shorter than in Comparative Example 1 in which these are not added. The mold release completion time is reduced by about 130 seconds, and the mold release completion time is reduced by about 190 seconds. This is an extremely excellent manufacturing method that shortens the molding cycle, improves productivity, and produces molded products with stable quality.

(Example) Examples are shown below.

What are the polymerization rate, mold release start time, and mold release completion time?

In each case, when the monomer solution mixed at 100°C was immediately put into a glass test tube kept in a 160°C oil bath to polymerize lactams, the monomer solution was The time from the start of mixing of the monomer liquid until a part of the produced polymer begins to release from the tube wall of the test tube, and the time from the start of mixing of the monomer liquid until the produced polymer completely leaves the test tube. means the time it takes for the mold to be released from the pipe wall.

Also, the solubility of fatty acid amide in lactams.

A fatty acid amide was added to a caprolactam solution heated to 100°C, and those that dissolved by weight of 5 or more were rated as Δ, those that dissolved by weight of 01 to 5 were rated as Δ, and those that dissolved by 1 or less by weight were marked as ×.

Example 1 Sodium methylate (95% purity) 0 to substantially anhydrous ε-caprolactam 1007 heated to 100°C
5y was added and methanol produced as a by-product was distilled off under reduced pressure to prepare an alkaline catalyst solution (component A).

To 100 parts of substantially anhydrous ε-caprolactam heated to 100°C, 0.0 parts of hexamethylene diisocyanate is added.
2f and N-butyl-cystearylurea 19 were added and stirred uniformly under a nitrogen gas atmosphere to prepare component B.

Mix and stir component A and component B, and immediately add 1
A test tube (inner volume: 250 cc, diameter: 3 cm, height: 36 cm) was placed in an oil path at 60'C, and polymerization was carried out under a nitrogen gas atmosphere at a polymerization rate of 1.

The mold release start time and mold release completion time were measured.

The solubility of N-butyl-cystearylurea in caprolactam was also measured. The results are shown in Table 1.

Comparative Example 1 The same method as Example 1 was repeated, except that N-butyl-cystearylurea was not added.

The results are shown in Table 1.

Comparative Example 2 The same method as in Example 1 was repeated except that polyethylene glycol monooleyl ether 12 was used in place of N-butyl-N'-stearylurea. The results are shown in Table 1.

Comparative Example 3 The same method as in Example 1 was repeated except that α-methylnaphthalene 12 was used in place of N-butyl-cystearylurea. The results are shown in Table 1.

Comparative Example 4 The same method as in Example 1 was repeated except that stearamide 17 was used in place of N-butyl-cystearylurea. The results are shown in Table 1.

Comparative Example 5 The same method as Example 1 was repeated except that m-xylylene pistearamide 12 was used in place of N-butyl-cystearylurea. The results are shown in Table 1.

Example 2 0.5 ml of sodium methylate was added to 200y of substantially anhydrous ε-caprolactam heated to 110°C, and by-produced methanol was distilled off under reduced pressure to prepare an alkaline catalyst liquid. .

After adding a predetermined amount of fatty acid amide listed in Table 2 to the above alkaline catalyst solution and mixing uniformly, hexamethylene-1,6-piscarpamide caprolactam 0,
7f was added. This mixed solution was polymerized in the same manner as in Example 1, and the polymerization rate, mold release start time, and mold release completion time were measured. The solubility was also investigated. The results are shown in Table 2.

Example 5 Substantially anhydrous ε in the A component tank of a nylon RIM molding device
- 4 kg of prolactam and 100 t of sodium caprolactam were added, and the temperature was maintained at 100°C.

The B component tank contains substantially anhydrous ε-force prolactam Z4.
9. Xylylene diincyanate 2232, Chefamine D-2000, (manufactured by Mikata Texaco Chemical) 1
．． 6 to 9. Glass cut fiber (manufactured by Fuji Fiber Glass ■, FESS-005-0413) 1.6 K
12 g of SI and N-oleyl stearamide were added and mixed uniformly at 100°C.

Component A and component B were supplied to a mixing head at a volume ratio of 1:1 and mixed by collision, and then injected from the mixing head into a box-shaped mold having an internal volume of 285 cc and heated to 140°C. The mold could be opened one minute after injection, and the molded product with a smooth surface could be easily removed.

Comparative Example 6 The same method as Example 5 was repeated, except that N-oleyl atearamide was not used.

The mold was opened 6 minutes after injection, but the molded product could not be immediately removed from the mold because most of the molded product was attached to the mold.

Table 1 〉

Claims (1)

[Claims] A method for polymerizing lactams by the action of an alkali catalyst and a cocatalyst, comprising the formulas RCONH(CH)_nNHCOR RCONHR' and RNHCONHR' (wherein, R and R' are saturated carbon atoms having 7 to 30 carbon atoms). or an unsaturated aliphatic group, and n is an integer of 5 to 10. Manufacturing method for polyamide molded products.