JPH07138365A - Product of blow molding - Google Patents

Abstract

PURPOSE:To obtain a blow molding not suffering from underfill and uneven thickness and being of high practical value by a simple operation by polymerizing omega-lactam and a polyamide in a rotary molding machine by feeding them thereto in the form of a powder or flakes. CONSTITUTION:A feedstock comprising a powdery or flaky omega-lactam (A), a powdery or flaky alkali polymerization catalyst or the omega-lactam (B) containing this catalyst, a powdery or flaky activator or the omega-lactam (C) containing this activator, a polyamide powder (D) having a particle diameter of 1-600mum and a number-average molecular weight of 1000-100000 and a liquid or powdery polyol component (E), the above components being used in amounts to give 40-99wt.% total of components A to C, 1-60wt.% component D and 0-55wt.% component E, is fed to a rotary molding machine and polymerized. By using the above polymerization material, a product of blow molding not suffering from underfill and uneven thickness and being of high practical value and heretofore not obtained by a rotary molding process can be obtained by a simple operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses anionic polymerization of a specific polyamide raw material in a rotary molding machine to obtain, for example, oil tanks for two-wheeled and four-wheeled vehicles and leisure / industrial vehicles, gasoline tanks, and rear spoilers for automobiles. It relates to hollow molded products such as.

[0002]

Polyamide resins are widely used as engineering plastics having excellent mechanical properties, heat resistance and chemical resistance. As a method for producing a hollow polyamide molded product by rotational molding, a powdered polyamide is heated in a rotating mold to a temperature equal to or higher than the melting point of the polyamide, and melted to form a molten polymer film on the inner wall surface of the mold, followed by cooling. A method of solidifying (eg, US Pat. No. 2629).
134, U.S. Pat. No. 3,439,079), ω-lactams such as alkali catalysts and triazine, pyridazine, cinnoline, phthalazine, pyridine, quinazoline, pyrazine, quinoline, quinoxaline, benzoxazole, benzothiazole, benzopyrazole, oxazine compounds. A method of anionic polymerization in a rotational molding machine with an activator (for example, JP-B-41-32, JP-A-47-13)
667, JP-A-47-18996, JP-A-51-106167) and the like are known.

[0003]

However, in the method of melt-casting in a rotary molding die using powdery polyamide, the time from raw material charging to molding to unloading is long, and the obtained molded product is polyamide. Since it is heated above the melting point, it has a drawback that the polymer is likely to deteriorate.

On the other hand, although the anionic polymerization method solves such a drawback, in the conventional anionic polymerization, in the case of a hollow molding having a large size and a complicated shape, the polymerization is performed after the raw materials are injected into the mold. By the time it is completed, the angular velocity of each part of the rotating mold is different, so that the raw material lactam drops, flows down and locally collects liquid, entrains air bubbles, causes uneven thickness,
It has a drawback that it tends to cause flesh. In order to form a uniform liquid film, a method of adjusting the rotation speed of a mold as disclosed in Japanese Patent Publication No. 41-32, JP-A-51-106.
Although a method of increasing the viscosity using a filler as disclosed in Japanese Patent No. 17 has been proposed, it is not always possible to obtain good results such as insufficient uniformity of wall thickness of a molded product. The current situation.

The object of the present invention is to solve the above-mentioned problems of the prior art. The inventors of the present invention use an anionic polymer material in rotational molding to easily form a molded product having a uniform thickness and high impact strength. After diligently studying how to obtain, ω
-The present invention has been achieved by finding that the objects can be achieved all at once by adding lactam and polyamide in the form of powder or flakes.

[0006]

Means for Solving the Problems That is, the present invention provides (1) (A) powder or flake ω-lactam, (B) powder or flake alkali polymerization catalyst or ω-lactam containing polymerization catalyst. , (C) a powdery or flake activator or an ω-lactam containing the activator, (D) a polyamide powder having a particle size of 1 to 200 μm and a number average molecular weight of 1000 to 100,000, and (E ) Consisting of a liquid or powdered polyol component,
A + B + C component is 40 to 99% by weight, D component is 1 to 60
A hollow molded article is provided in which a raw material prepared by blending the component E in an amount of 0 to 55% by weight is charged into a mold and polymerized in a rotary molding machine.

A technical feature of the present invention resides in that a powder or flake mixture of ω-lactam or a composition thereof is used to anionically polymerize in a rotary molding machine to form a hollow molded article, and a polyamide powder or flake is added. And then ω−
By increasing the flow viscosity of the lactam solution, it is possible to manufacture a practical hollow molded product having a uniform wall thickness.

The present invention will be described in detail below.

The shape of the powder or flakes of ω-lactam used in the present invention is not particularly limited, but particularly ω-
80% by weight or more of lactam has a maximum length of 0.05 to 20 m
It is preferably a flake-like powder in the range of m, preferably 0.05 to 10 mm. Maximum length is 0.05m
If it is less than m, nodules tend to be generated in the initial stage of melting, and if the maximum length exceeds 20 mm, heat conduction is insufficient, so uneven thickness and lack of thickness of the molded product due to uneven melting tend to occur. Further, the weight of the ω-lactam having the above shape is 80% of the whole.
If it is less than wt%, the effect due to the shape of the flakes is reduced.

The ω-lactam used in the present invention is a cyclic amide compound having 4 to 12 carbon atoms, and examples thereof include pyrrolidone, valerolactam, caprolactam, enantolactam, capryllactam and laurolactam. These ω-lactams can be used in a mixture of two or more kinds. As the activator used in the present invention, a conventionally known activator which is usually used for alkaline polymerization of ω-lactam can be used. For example, 1,4-tetramethylene diisocyanate, 1,6
-Hexamethylene diisocyanate, 1,11-undecamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, β-methylbutane diisocyanate, butene diisocyanate, ω, ω'-dipropyl ether diisocyanate, 1,4-dibutanediol dipropyl Ether diisocyanate, thiodiethyl diisocyanate, ω, ω'-diisocyanate-1,3-
Dimethylbenzene, ω, ω'-diisocyanate-1,
2-dimethylbenzene, ω, ω'-diisocyanate-
1,2-dimethylcyclohexane, ω, ω′-diisocyanate-1,4-dimethylcyclohexane, ω, ω ′
-Diisocyanate-1,4-diethylbenzene, ω,
ω'-diisocyanate-1,4-dimethylnaphthalene, ω, ω'-diisocyanate-1,5-dimethylnaphthalene, 1-ω-methylisocyanate-2-ω-propylisocyanate-3,5-dimethylcyclohexane, ω, ω '-Diisocyanate-n-propylbiphenyl, 1,3-phenylene diisocyanate, 2,4,
2,5,2,6,3,5-tolylene diisocyanate 1,3-dimethylbenzene-2,4-diisocyanate, 1,3-dimethylbenzene-4,6-diisocyanate, 1,4-dimethylbenzene-2, 5-diisocyanate, naphthalene-1,4,1,5-, 2,6-,
2,7-diisocyanate, 1,1'-dinaphthyl-
2,2'-diisocyanate, biphenyl-2,4 ',
4,4'-diisocyanate, diphenylene methane-
4,4'-diisocyanate, 2,2'-dimethyldiphenylmethane-4,4'-diisocyanate, cyclohexyl- (4-isocyanatephenyl) methane, dicyclohexylmethane-4,4'-diisocyanate,
3,3′-dimethoxydiphenylmethane-4,4′-diisocyanate Benzophenone-3,3′-diisocyanate, α, β-diphenylethane-1,4-diisocyanate, thioisocyanate compounds corresponding thereto, pyrrolidone, ε- Compounds synthesized by adding caprolactam, ω-laurolactam, and N, N′-dimethyl-1,4-tetramethylenediamine, N, N′-dimethyl-1,6-hexamethinediamine, N, N ′ -Diethyl-1,6-hexamethinediamine, N-methyl-N'-propyl-1,6-hexamethylenediamine, N, N'-dimethyl-1,4-cyclohexanediamine, N, N'-dimethyl-meta Xylylenediamine, N, N'-dicyclohexyl-paraxylylenediamine, N, N'-diphenyl Ru-paraphenylenediamine and the like phosgene, after reacting thiophosgene to bischloroformate, at least one compound selected from compounds synthesized by further adding pyrrolidone, caprolactam, and acid chloride in a solvent Compounds obtained by reacting with ω-lactam, for example, acetylcaprolactam, benzoylcaprolactam, adipoylbiscaprolactam, terephthaloylbiscaprolactam, chloroterephthaloylbiscaprolactam, 2,3-diethylsuccinoylbiscaprolactam, sebacylbis. Representative activators include caprolactam and isophthaloylbiscaprolactam. Each of these activators can be used alone or in the form of a mixture. The amount of activator added is ω-
The amount is preferably 0.05 to 10 mol% with respect to the lactam, and more preferably 0.1 to 6 mol%. The activator may be added in the form of a compound, but once dissolved in the ω-lactam to form a high concentration activator solution, cooled and solidified (hereinafter referred to as the activator solid solution), Is preferably crushed before use. The concentration of the activator in the solid solution is usually 5 to 60% by weight, preferably 10 to 50% by weight.
The shape of the activator or its solid solution may be powder or flake, and is not particularly limited, but is preferably equal to or less than the shape of ω-lactam. Hereinafter, the activator is meant to include the solid solution thereof.

The polymerization catalyst used in the present invention is not particularly limited, and generally known compounds can be used.
Typical examples are salts of alkali metals such as sodium lactamate and calcium lactamate, alkaline earth metals and ω-lactam, or alkaline substances capable of forming ω-lactam and lactamate anion in the system. Examples of these include alkali metals, alkaline earth metals and hydrides, hydroxides, oxides, carbonates, alkoxy compounds, aryl compounds or trialkylaluminums of these metals, Grignard reagents, and the like. These catalysts can be used alone or as a mixture of two or more kinds, and the addition amount thereof is 0.1 to 10 mol%, more preferably 0.3 to 5 mol% with respect to the ω-lactam monomer. The range is appropriate. Similarly to the activator, the polymerization catalyst can be used as a high-concentration solid solution. The concentration of the solid solution is usually 5 to 30% by weight, preferably 10 to 20% by weight. The shape of the polymerization catalyst or its solid solution is not particularly limited as long as it is in the form of powder or flakes, but is preferably equal to or less than the shape of ω-lactam. Hereinafter, the polymerization catalyst is meant to include a solid solution thereof.

The polyamide powder or flakes which can be used in the present invention may be those which are dissolved in the ω-lactam solution, some of which may be dissolved, or all of which may be insoluble. , Preferably 100-180
A polyamide insoluble in ω-lactam under the temperature condition of ° C is used.

Examples of polyamide powders or flakes suitable for such purpose are nylon 6 produced from ε-caprolactam, nylon 11 produced from ω-aminoundecanoic acid, and nylon 12 produced from ω-aminododecanoic acid. , Polycondensates of dicarboxylic acids and diamines (for example, nylon 66 manufactured from adipic acid and hexamethylenediamine, nylon 610 manufactured from sebacic acid and hexamethylenediamine, manufactured from dodecanedioic acid and hexamethylenediamine) Nylon 61
2. Nylon 46 manufactured from adipic acid and tetramethylenediamine, polycondensation product of aromatic dicarboxylic acid and aliphatic diamine (for example, nylon 6T manufactured from terephthalic acid and hexamethylenediamine (T is terephthalic acid) Nylon 6I (I represents isophthalic acid) produced from isophthalic acid and hexamethylenediamine, terephthalic acid, copolymerized nylon 6T / 6I produced from isophthalic acid and hexamethylenediamine, terephthalic acid, adipic acid Nylon 6T / 66, a nylon 6/66 copolymer, a nylon 6/66/610 copolymer, and a nylon 6 produced by copolymerizing the above nylon raw materials.
/ 12 copolymer, nylon 6/66/610/612 copolymer, nylon 6 / 6T copolymer, nylon 6/66
/ 6T copolymer, nylon 66 / 6T / 6I copolymer,
Nylon 6 / 6T / 6I Copolymer, Nylon 6/66 /
Specific examples include terpolymers such as 6T / 6I copolymers and quaternary copolymers.

The number average molecular weight of the above polyamide is 1000.
It is preferably in the range of 100,000. When the number average molecular weight is less than 1000, the moldability is not greatly affected, but the physical properties of the obtained molded product are significantly reduced. The number average molecular weight is 1
Use of a polyamide of more than 0,000 is meaningless because it has no effect of improving the moldability and the physical properties of the molded product.

There is no limitation on the method for producing the polyamide powder, and the polyamide powder may be produced by a known method. Generally, those frozen and pulverized with liquid nitrogen can be used, but anionically polymerizable substances such as ω-lactam can be obtained as fine powders by polymerizing with stirring in a suitable solvent. You can also It can also be produced by dissolving nylon in a solvent such as sulfuric acid or meta-cresol and dropping it with stirring into a liquid that is a poor solvent for nylon such as water or methanol. The shape of the powder or flakes is preferably equal to or less than that of the ω-lactam. More preferably the particle size is 1-600μ
It is in the range of m.

The amount of polyamide powder or flakes added is 1 to 60% by weight, more preferably 3 to 45% by weight. If the amount added is less than 1% by weight, there is no effect of increasing the flow viscosity, and it is not possible to eliminate the uneven thickness and lack of thickness which is the object of the present invention. Since the flow viscosity increases too much, a molded product having a uniform wall thickness cannot be obtained, which is not preferable.

The polyol which can be used in the present invention has at least two hydroxyl groups, and preferably has a molecular weight of 200 to 10,000, more preferably 300 to 5,
Polymers in the range of 000, typical examples of which are polyethylene glycol, polypropylene glycol, poly (oxyethylene / oxypropylene) glycol, polypropylene triol, polytetramethylene glycol, glycerin, trimethylolpropane,
Ethylene oxide and / or pentaerythritol
Further, there may be mentioned polyether polyols obtained by polymerizing addition of propylene oxide, polyester polyols such as poly ε-caprolactone diol, polyester polyols such as polybutadiene diol, polybutadiene diol, poly (butadiene / styrene) copolymer diol and the like. These polyols can be added alone or in combination of two or more. The addition amount of the polyol is appropriately in the range of 0 to 55% by weight. Addition of polyols is useful for further enhancing the object of the present invention. When the amount of the polyol added exceeds 55% by weight, the strength, rigidity and heat resistance of the produced polymer are insufficient, and the characteristics of the polyamide cannot be fully exhibited, which is not preferable. The polyol is usually in a liquid state, and as a method of addition, it is preferable to add it to a powdery material and sufficiently blend it. In addition, if they are powdery, they can be mixed in any order.

The polymerization method and polymerization conditions of the present invention are not particularly limited, and conventionally known methods can be adopted. For example, a composition comprising ω-lactam, polyamide powder or flakes and a polyol, polymerization catalyst and activator powder or flakes is mixed together,
A method of introducing the mixture into a molding die and polymerizing it, or mixing the required amount of each of ω-lactam, activator, polyamide powder or flakes and polyol and a polymerization catalyst powder or flakes immediately before the introduction into the die. Together, such as a method of introducing into the mold, or a method of individually charging the raw material powder or flakes into the mold, such as batch mixing of the materials to be used and two or more divided mixing,
It may be mixed by any method and charged into the mold.
In addition, in order to manufacture a hollow molded product having a uniform wall thickness, in any of the above mixing methods, the material is charged into the mold once (total amount) or twice (for example, half amount each) or more. It is also effective to use a divided charging method in which the charges are divided into two. Particularly, it is effective to perform the injection in two or more times for a hollow molded product having a complicated shape. Further, the split charging method is an effective method for molding a hollow molded article having no bubbles on the surface and inside when a mat and cloth are filled as a reinforcing agent in the mold. Further, when molding a hollow molded article having a multi-layered resin layer by split charging, it is necessary to use two or more kinds of materials having different compositions in combination so as to improve impact strength, heat resistance, rigidity and surface smoothness. Particularly effective in quality. The polymerization temperature is appropriately set to a temperature equal to or higher than the melting point of the ω-lactam monomer, and usually 110 to 10.
The temperature range is 320 ° C., preferably 120 to 270 ° C., more preferably 130 to 200 ° C., and it is preferable to select conditions under which a good hollow molded article can be obtained. For this reason, the temperature of the heating furnace for heating the mold should be set such that the polymerization temperature is such that a good hollow molded product can be obtained.

According to the molding method of the present invention, after the material is poured into the mold and before the completion of the polymerization, the mold is set on one or two or more rotating shafts set at arbitrary positions. On the other hand, it can be carried out by utilizing a known rotational molding method capable of rotating, reversing or pendulum motion in one direction. At this time, it is preferable that the inside of the mold is replaced with an inert gas such as nitrogen so as to be essentially anhydrous.

In the hollow molded article of the present invention, if necessary, glass fiber, carbon fiber, asbestos fiber, wholly aromatic polyamide fiber, polyamide powder soluble in ω-lactam, powder of polyester or the like, inorganic material such as staple or the like or Organic fibrous reinforcements or powders such as talc, wollastonite, bentonite, montmorillonite, calcium carbonate, magnesium oxide, alumina, mica, glass beads, potassium whiskers, spherical fillers, molybdenum disulfide, paraffin, silicone A sliding material such as can be introduced. Milled fiber for fibrous reinforcement,
It can be used in any shape such as roving, mat or cloth. Further, the hollow molded article of the present invention has other components as long as it does not impair the moldability, for example, an internal release agent such as a stearic acid metal salt composed of magnesium stearate and aluminum stearate, a pigment, a dye, Flame retardants, heat resistance agents, antioxidants, weathering agents, lubricants, release agents, antistatic agents, plasticizers, crystal nucleating agents, foaming agents, other polymers (for example, ethylene / acrylic acid copolymers, ethylene / Methacrylic acid copolymers and those in which some or all of the carboxylic acid moieties in these copolymers are salts with sodium, lithium, potassium, zinc, calcium (ionomer resins) ethylene / methyl acrylate copolymers, ethylene / Ethyl acrylate copolymer, ethylene /
Ethyl acrylate-g-maleic anhydride copolymer ("g" represents a graft, the same applies hereinafter), ethylene / methyl methacrylate-g-maleic anhydride copolymer, ethylene / ethyl acrylate-g-maleimide copolymer Polymers, ethylene / ethyl acrylate-g-N-phenylmaleimide copolymers and partially saponified products of these copolymers, ethylene / propylene copolymers, ethylene / propylene /
1,4-hexadiene copolymer, ethylene / propylene / dicyclopentadiene copolymer ethylene / propylene / 2,5-norbornadiene copolymer, ethylene / butene copolymer and their α, β-unsaturated carboxylic acid ( For example, co-polymer modified with maleic acid, maleic anhydride, maleic anhydride imide, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, acrylic acid ester (methyl methacrylic acid ester, glycidyl methacrylic acid ester, etc.), crotonic acid, etc. A polymer block mainly composed of at least one vinyl aromatic compound (styrene, o-methylstyrene, p-methylstyrene, α-methylstyrene, 1,3-dimethylstyrene, vinylnaphthalene, etc.) and at least one polymer block Conjugated diene compound (1,
3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene,
1,3-pentadiene, 1,3-hexadiene, etc.)
And hydrogenated block copolymers of the block copolymers, as well as copolymers thereof modified with the above α, β-unsaturated carboxylic acid, polyethylene, polystyrene, polypropylene and α, β-unsaturated carboxylic acids thereof. Polymer modified with acid, polyvinyl chloride, polyvinylidene chloride, vinyl acetate, polyvinyl acetate resin, polyester resin, polyphenylene ether resin, polyphenylene sulfide resin, polyacetal resin, polycarbonate resin, polyether sulfone, polyallyl Sulfone, polyurethane resin, polybutadiene resin, polyketone resin, polyarylate resin, fluororesin, polyoxybenzoyl resin, polyimide resin, ABS
Examples thereof include resins, phenol resins, phenoxy resins, epoxy resins, silicone resins and the like. These resins may be added alone or as a mixture of two or more kinds. The particle size of these polymers is not specifically defined, but generally 0.2 μm.
It is preferable to use a fiber having a diameter of 1 to 50 μm and a fiber length of 100 to 10 mm. ) Etc. can be added and introduced.

The hollow molded article made of the polyamide of the present invention obtained as described above is used to mold hollow molded articles having various cross sections such as various machine parts, oil tanks for automobiles, gasoline tanks and rear spoilers for automobiles. Applicable to

[0022]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited to these examples.

The hollow molded articles were evaluated according to the following methods.

(1) Surface appearance: macroscopic judgment (2) Wall thickness: macroscopic judgment after cutting ・ The lack of wall thickness means an extremely thin wall or a hole.

The term "uneven thickness" refers to a situation in which a thin portion and a thick portion are unevenly distributed.

Example 1 Flakes (thickness 1 mm or less, width 6 mm or less, length 16)
mm) or less), 800 g of ε-caprolactam, 100 g of a solid solution powder of ε-caprolactam containing 17% by weight of sodium caprolactam (abbreviated as Na-CL) as a polymerization catalyst, 1,6-hexamethylene diisocyanate and ε-as activators. Reaction product with caprolactam (HD-
100 g of a solid solution powder with ε-caprolactam containing 39% by weight of 2CL and 100 mesh sieve (1
200g of Nylon 6 powder that has passed 50 μm) is mixed together and charged into a mold attached to a McNeill type rotary molding machine, and then the rotation speed of the mold is adjusted within a range of 10 to 27 rpm, and the conditions shown in Table 1 are applied. Molding was carried out. Polymerization is about 14
Completed in minutes, a molded product was obtained. The releasability of the molded product from the mold and the surface appearance were good, and the molded product obtained here was cut to evaluate the lack of wall thickness and uneven thickness, and the results shown in Table 1 were obtained. Molded products with good mold releasability, smooth appearance, and less wall thickness / uneven thickness were obtained.

Comparative Example 1 Among the materials used in Example 1, the same operation as in Example 1 was carried out except that nylon 6 powder was not added, and molding was performed under the conditions shown in Table 1. Although the mold releasability and the appearance were not much different from those in Example 1, there were missing thicknesses and uneven thicknesses, and excellent molded products could not be obtained.

Examples 2 to 5 The same operation as in Example 1 was carried out except for the conditions shown in Table 1 to obtain hollow molded articles. In all cases, a hollow molded article having good mold releasability, a smooth appearance, and a small amount of wall thickness and uneven thickness, which was the object of the present invention, was obtained.

[0029]

[Table 1]

[0030]

By using the anionic polymer material of the present invention, it is possible to obtain a hollow molded product which is easy to operate and has no practically lacking thickness or uneven thickness which could not be achieved by the conventional rotary molding. You can

Claims (1)

[Claims] 1. A powdery or flake ω-lactam, a powdery or flake ω-lactam containing an alkali polymerization catalyst or a polymerization catalyst, and a powdery or flake activation. Ω- containing an agent or activator
A lactam, (D) a particle size of 1 to 600 μm, a polyamide powder having a number average molecular weight of 1000 to 100,000, and (E) a liquid or powdery polyol component, and A + B + C component of 40 to 99% by weight, D 1 to 1
A hollow molded article obtained by charging a raw material containing 60% by weight and E component of 0 to 55% by weight into a mold and polymerizing the mixture in a rotary molding machine.