JPH04370116A - Polyamide, polyamide resin composition and blow molded article - Google Patents

Abstract

PURPOSE:To obtain a polyamide, which is a copolyamide comprising a given amount of a polyamide component composed of hexamethylene adipamide component, etc., as raw materials, useful as molded articles, etc., having a specific melting point, a specific crystallization temperature, excellent heat resistance, chemical resistance and excellent low water absorption. CONSTITUTION:The objective crystalline polyamide which is a copolyamide comprising (A) 50-90wt.% hexamethylene adipamide component, (B) 5-40wt.% hexamethylene terephthalamide component, (C) 4-30wt.% hexamethylene isophthalami) 1-10wt.% polyamide component composed of 6-12C cyclic lactam and/or 6-12C aminocarboxylic acid as a raw material, having melting point (Tm) and crystallization temperature (Tc) satisfying Tm >=225 deg.C and Tc <=220 deg.C, respectively. A composition obtained by blending 50-99wt.% of the polyamide with 1-50wt.% fiber reinforced material readily provides blow molded articles.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] Polyamide resins are widely used as engineering plastics due to their excellent physical properties. In particular, with the recent weight reduction of automobiles, the emergence of polyamide resin compositions with well-balanced physical properties such as heat resistance, impact resistance, chemical resistance, road antifreeze resistance, low water absorption, and dimensional stability is desired. There is.

[0002] The present invention relates to a polyamide resin composition having excellent heat resistance, impact resistance, chemical resistance, road antifreeze resistance, low water absorption, and dimensional stability, and mechanical parts using the polyamide resin composition. , relates to blow-molded products used in automotive parts applications.

0003

[Prior Art] As a blow molding material, hexamethylene adipamide (hereinafter abbreviated as 66), hexamethylene terephthalamide (hereinafter abbreviated as 6T), and hexamethylene isophthalamide (hereinafter abbreviated as 6I) are used as ingredients. polyamides are already well known. For example, JP-A-61-2001
Publication No. 23 discloses a copolyamide containing 30 to 51.5% by weight of the 66 component, 48.5 to 60% by weight of the 6T component, and 0 to 10% by weight of the 6I component. Stability is very poor, making molding difficult, and even if a molded product is obtained, its properties tend to fluctuate and reproducibility cannot be achieved. Further, although the polyamide in this composition range is crystalline, the Tc is 220° C. or higher, and it is impossible to solidify the parison quickly in three-dimensional blow molding. 66, 6T, 6I series and polycaprolactam (hereinafter simply abbreviated as 6), 6T, as blow molding materials
6I-based polyamides include JP-A-63-94842, JP-A-63-120645, and JP-A-1-1.
Publication No. 76555 may be cited.

[0004] These known examples commonly describe copolyamides consisting of 6 or aliphatic polyamide/6T/6I components as polyamides. That is, specifically, the 6 components were 15% by weight, the 6T component was 28.3% by weight, and the 6T component was 28.3% by weight.
A polyamide comprising 56.7% by weight of component I is shown. The polyamide in this composition is an amorphous polyamide according to the experiments conducted by the present inventors, and is not a polyamide having the physical properties intended by the present inventors. In other words, it has poor thermal stability because it contains a large amount of 6I component, and its chemical resistance is particularly poor because it is amorphous in terms of physical properties, so it is difficult to find a material with a good balance of heat resistance and rigidity. I can't do it.

[0005] Also, as materials for polyamide plastic blow molding, nylon 6, 66, etc., and materials in which impact modifiers and reinforcing agents are added to nylon 6, 66, etc. are widely known (Japanese Patent Publication No. 55-41659). Publication No.). However, even if one attempts to obtain a three-dimensional blow-molded product with a relatively long parison length using these materials, the product may thicken or decompose due to residence at high temperatures during molding, or the appearance of the resulting molded product may deteriorate. The heat resistance is poor, and even if the heat resistance is good, the parison solidifies quickly due to the high crystallization temperature.
The reality is that there is no material for three-dimensional blow molding with well-balanced physical properties, as it is not possible to obtain long parisons or it is not a material that is sufficiently satisfactory for obtaining three-dimensional blow molded products.

[0006]

[Problem to be Solved by the Invention] However, as mentioned above, in recent years, as automobile parts have become lighter, the characteristics required for resin molded products that replace metals have become even more stringent. . Particularly in the engine room and directly connected to the engine, such as resonators, air spoilers, air inlet tubes, duct air intakes, intake manifolds, water pipes, radiator tanks, etc. Heat resistance, chemical resistance, low water absorption, road anti-freezing Materials with well-balanced physical properties such as agent properties and dimensional stability are required. These resins not only have the above-mentioned balance of physical properties, but also materials that can be three-dimensionally blow molded into complex shapes, that is, long parisons with improved drawdown properties can be easily formed, and thermal stability during molding. The material must have good properties and the surface appearance of the resulting molded product.

The object of the present inventors is to obtain polyamides, polyamide resin compositions, and blow-molded products thereof having well-balanced physical properties as described above.

[0008]

[Means for Solving the Problems] That is, the present invention provides (1)
) (a) hexamethylene adipamide component 50-90% by weight, (b) hexamethylene terephthalamide component 5-4
0% by weight, (c) hexamethylene isophthalamide component 4 to 30% by weight, (d) polyamide components 1 to 1 made from a cyclic lactam having 6 to 12 carbon atoms and/or an aminocarboxylic acid having 6 to 12 carbon atoms. A crystalline polyamide (2
) A polyamide resin composition comprising 50 to 99% by weight of the polyamide described in (1) above and 1 to 50% by weight of a fibrous reinforcing agent; (3) A polyamide described in (1) above, which has Tm+
A blow-molded product made of a polyamide whose melt viscosity μa (poise) measured at 20° C. and a shear rate of 10 (1/sec) satisfies 2,000,000≧μa≧2,000, and (4) the above ( 2
) The polyamide resin composition described in Tm+20°C
, melt viscosity measured at a shear rate of 10 (1/sec) (
The present invention provides a blow molded product using a polyamide resin composition that satisfies the following: 2,000,000≧μa≧2,000. In the present invention, (a) 66, (b)
) 6T, (c) 6I, (d) It is important to use a polyamide made from a cyclic lactam having 6 to 12 carbon atoms and/or an aminocarboxylic acid having 6 to 12 carbon atoms. Furthermore, the inventors have discovered that it is possible to prepare a material that can be three-dimensionally blow-molded, which allows relatively long parisons to be easily obtained, and which has significantly improved retention stability compared to conventional compositions, resulting in the present invention. did.

In other words, the characteristics of the present invention are to optimize the melting point, crystallization temperature, and melt viscosity of the polyamide by specifying the composition of each polyamide component, and to improve the retention stability during molding, thereby improving the physical property balance. swollen,
Moreover, it has made it possible to prepare a material with excellent thermal stability. In other words, it was surprisingly discovered that the stability during melt retention is significantly improved by introducing component (d).Moreover, this material can easily be used to obtain long parisons in blow molding, and is especially suitable for three-dimensional blow molding. The present invention is based on the discovery that it is a crystalline polyamide resin material that can be molded.

The present invention will be described in detail below.

The polyamide of the present invention contains (a) 50 to 90% by weight of the 66 component, (b) 5 to 40% by weight of the 6T component,
(c) 6I component 4-30% by weight (d) Number of carbons, 6-30% by weight
This is a crystalline polyamide prepared within a composition range of 1 to 10% by weight of the polyamide component, which is made from 12 cyclic lactams and/or an aminocarboxylic acid having 6 to 12 carbon atoms. If the amount of component 66 is less than 50% by weight, the crystallinity of the resulting polyamide will be low and the balance of physical properties such as chemical resistance will be poor, and if it exceeds 90% by weight, the crystallization temperature will be 2.
If the temperature exceeds 30°C, it becomes impossible to obtain a sufficiently long parison during blow molding, which is not preferable. Moreover, when the 6T component is less than 5% by weight, the melting point of the obtained polyamide is 2.
If it becomes lower than 25℃, the balance of heat resistance will deteriorate, and the temperature will decrease to 40℃.
If it exceeds % by weight, the heat resistance will improve, but the crystallization temperature will exceed 230°C, which will cause the parison to solidify during blow molding, which is undesirable. Furthermore, regarding the 6I component 4
If it is less than 23% by weight, the heat resistance will improve, but the crystallization temperature will also be 23%.
If it exceeds 0°C, it becomes a factor that promotes solidification of the parison during blow molding, and if it exceeds 30% by weight, thermal stability deteriorates.
Since the 6I component is amorphous, crystallinity and heat resistance are reduced, which is not preferable. Furthermore, the component (d) is 1% by weight.
If it is less than 10% by weight, thermal stability will not be improved, and if it exceeds 10% by weight, thermal stability will be improved, but crystallinity and heat resistance will deteriorate, which is not preferable. That is, the polyamide of the present invention reduces the crystallinity of nylon 66 by introducing the 6I component, improves blow moldability, and improves the blow moldability of nylon 66.
It is based on the design concept of compensating for the decrease in heat resistance due to the addition of components by adding the 6T component, and providing thermal stability with component (d). The component (d) used here is a polyamide component obtained from a cyclic lactam having 6 to 12 carbon atoms and/or an aminocarboxylic acid having 6 to 12 carbon atoms, specifically caprolactam, ε-
Examples include nylon 6, nylon 11, and nylon 12 components obtained from aminocarboxylic acids, aminododecanoic acid, laurolactam, aminoundecanoic acid, etc., and nylon 6 components are usually preferably used.

The degree of polymerization of the polyamide used here is not particularly limited, but in order to obtain stable polymer discharge from the polymerization pot, it is usually 98 in accordance with JIS K6810.
% Concentration in sulfuric acid 1%, relative viscosity measured at 25°C is 1.5
It is desirable that it be in the range of 1.5 or more and less than 5.0, particularly 1.5 or more and less than 5.0.

Polyamide polymerization methods include melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid phase polymerization, and combinations thereof, with melt polymerization being generally most suitable. The raw materials for the components (a), (b), and (c) may be charged into the polymerization reactor in the form of 66 salt, 6T salt, or 6I salt, or may be charged in the form of their respective monomers.

[0014] A preferred embodiment also includes further performing solid phase polymerization after melt polymerization in order to obtain a desired melt viscosity.

In solid phase polymerization, a phosphorus compound or the like may be added as a polymerization accelerator. As the phosphorus compound, phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid, and alkaline earth metal salts thereof are effectively used. In particular, phosphoric acid is commonly used. The amount of the phosphorus compound added is not particularly limited, but is 0.01 or more and less than 5%,
In particular, 0.05 or more and less than 2% is preferably used. One or more types of phosphorus compounds can be used in combination. A commonly known method can be used for adding the phosphorus compound. For example, by adding a phosphorus compound or an aqueous solution of a phosphorus compound to polyamide resin pellets, powder, pieces, etc.,
A mixing method using a Henschel mixer, tumbler, ribbon mixer, etc. is preferably used. As a method of adjusting the melt viscosity, in addition to solid phase polymerization, it is also possible to melt-knead the polyamide resin to which the above-mentioned phosphorus compound is added. A known extruder can be used for melt-kneading.

The melting point of the polyamide used here is 22
It is necessary that the temperature is 5°C or higher, more preferably 235°C or higher. If the melting point is lower than 225°C, sufficient heat resistance cannot be obtained. Although there is no particular upper limit to the melting point, approximately 300°C is appropriate from the viewpoint of operability during polymerization and moldability during molding.

[0017] The crystallization temperature is 220°C or less, preferably 220°C or less.
A temperature of 10° C. or lower is effective for obtaining a relatively long parison. If the temperature is higher than 220°C, the parison solidifies quickly, making it impossible to obtain the desired parison length. The lower limit of the crystallization temperature is not particularly limited, but is generally the temperature at which crystallization can occur at room temperature, that is, 4
Approximately 0°C is appropriate.

[0018] Tm+20°C, shear rate 10 (1/se
The melt viscosity μa (poise) measured in c) is 2,00
It is preferable that the range is 0,000≧μa≧2,000. If the melt viscosity is less than 2,000 poise, drawdown of the parison occurs, which is undesirable, and if it is greater than 2,000,000 poise, moldability deteriorates, which is undesirable. The above also applies to polyamide resin compositions reinforced with fibrous reinforcing agents.

Fibrous reinforcing agents that can be used in the present invention include, for example, aramid fibers, polyamide fibers, glass fibers,
Examples include carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, zirconia fibers, potassium titanate whiskers, and glass fibers and carbon fibers are particularly preferred. Even if these fibrous reinforcements are left untreated,
Or a silane coupling agent with good thermal stability, such as triethoxy-γ-aminopropylsilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxy It may be surface-treated with silane or the like, and it is also possible to use two or more of these fibrous reinforcing agents. Furthermore, in addition to fibrous reinforcing agents, so-called inorganic fillers such as talc, kaolin, gypsum, mica, quartz, calcium carbonate, magnesium hydroxide, calcium phosphate, titanium phosphate, sericite, anhydrous mica, wollastonite, diatomaceous earth can be added. , white clay, white carbon,
Carbon black, zinc powder, etc. can be added.

The polyamide resin composition of the present invention contains 50 to 99% by weight, preferably 55 to 95% by weight of polyamide, and 1 to 50% by weight, preferably 5 to 45% by weight, of fibrous reinforcing agent.
It is composed of materials that are mixed by weight%. If the blending amount of the reinforcing agent exceeds 50% by weight, the characteristics of the polyamide will not be exhibited and the original purpose will be different, which is not preferable. On the other hand, if the amount of the fibrous reinforcing agent is less than 1% by weight, the effect of the reinforcing agent will not be expressed, and the purpose of obtaining a reinforced polyamide molded product will not be achieved.

The method of mixing the polyamide resin and the fibrous reinforcing agent is not particularly limited, and any commonly known method can be used. For example, polyamide resin pellets, powder, pieces, etc. and a fibrous reinforcing agent are mixed uniformly in a known mixer (Henschel mixer, tumbler, ribbon mixer, etc.), and then melt-kneaded in an extruder with sufficient mixing capacity. A suitable method is to prepare a polyamide resin composition and then blow mold it. Further, in blow molding, it is also possible to use an extruder or the like to knead and mold the material directly in the molding machine without kneading and pelletizing it, followed by molding. The mixture of polyamide and fibrous reinforcing agent, which is the raw material for obtaining the blow molded article of the present invention, also has a Tm+
It is necessary that the melt viscosity μa (poise) measured at 20° C. and a shear rate of 10 (1/sec) is within the range of 2,000,000≧μa≧2,000.

When the polyamide composition, which is the raw material for obtaining the blow-molded product of the present invention, is to be kept in a high-temperature molten state for a long time as in the case of molding the polyamide composition using a blow molding machine equipped with an accumulator, the It is useful to add a heat stabilizer for heat stability. As the heat-resistant agent, copper compounds such as copper halides such as copper acetate, copper iodide, copper chloride, and copper bromide can be used. The amount of copper compound added is 0.0 per 100 parts by weight of polyamide.
It is preferably 0.05 or more and less than 0.5 parts by weight, particularly preferably 0.01 or more and less than 0.1 parts by weight. Copper compounds are also effective in combination with alkali halides such as potassium iodide, potassium chloride, and sodium iodide. The amount of the alkali halide added is preferably 0.05 or more and less than 1 part by weight, particularly 0.05 or more and less than 1 part by weight, based on 100 parts by weight of the polyamide.
1 or more and less than 0.5 parts by weight are preferably used. Further, as other heat-resistant agents, antioxidants or hindered phenol compounds, phosphite compounds, thioether compounds, etc., which are commercially available as antioxidants, can also be suitably used. These antioxidants and antioxidants are 1
A mixture of more than one species can be used. The amount added is generally 0.01 or more and less than 5 parts by weight, particularly preferably 0.05 or more and less than 2 parts by weight, per 100 parts by weight of the polyamide. The timing of adding the above-mentioned heat-resistant stabilizer is not particularly limited, and may be added before, during, or after polymerization of the polyamide, and in the composition, it may be added at any stage before, during, or after kneading. You may.

The blow-molded product of the present invention may contain other components such as polyamide components other than the present invention, impact modifiers, pigments, lubricants, mold release agents, flame retardants, etc. to the extent that their moldability and physical properties are not impaired. can be added and introduced.

[0024] The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Regarding each evaluation,
It was measured according to the method described below.

(1) Melting point, crystallization temperature DSC (PER
The melting point (Tm) and crystallization temperature (Tc) were measured using a KIN-ELMER Model 7). Conditions are temperature increase 20℃/min
, hold at Tm+20℃ for 5 minutes, cool down 20℃/min
, Tc was maintained at -20°C for 5 minutes, and the temperature was increased at a rate of 20°C/min. The sample amount was approximately 8 mg.

(2) Melting point +20°C using retention stability melt indexer (Toyo Seiki Seisakusho)
The thermal stability of the polymer was examined.

(3) Water Absorption The saturated water absorption rate at 23°C was determined according to ASTM D570.

Examples 1 to 2, Comparative Example 1 Component 66, component 6T, component 6I, and caprolactam (6 components) were prepared in the composition shown in Table 1, melt polymerized, and further solid-phase polymerized to form copolyamide pellets. I got it. 4 more
Using a blow molding machine with an extruder of 0 mmφ, the outer diameter is 20 mm.
A parison with a thickness of 4 mm and a wall thickness of 4 mm was molded into a complex-shaped pipe with an outer diameter of 50 mm and a length of 1,000 mm using a mold for a three-dimensional blow molding machine. Examples 1 and 2 are nylon 6
It had lower water absorption than Nylon 66 and excellent thermal stability, and its blow moldability was also good with a Tc lower than that of Nylon 66 by 33 to 43°C. Comparative Example 1 had no problem with thermal stability, but due to the high Tc, the tip of the parison solidified during blow molding, and a good molded product could not be obtained.

Comparative Examples 2 to 5 Evaluation was carried out in the same manner as in Example 1, but in the case where the composition of 66 components was outside the range of the present invention (Comparative Example 2), drawdown occurred during blow molding. There was unevenness in the wall thickness of the molded product. In addition, the heat resistance is nylon 6 (Tm=22
5°C). The product in which the aminocarboxylic acid component was outside the range of the present invention (Comparative Example 3) had good blow moldability, but could not be said to have good thermal stability. The product in which the 6I component was outside the range of the present invention (Comparative Example 4) became amorphous and could not be subjected to solid phase polymerization, and could not be evaluated. 6
A product in which the 6, 6T, and 6I components were outside the range of the present invention (Comparative Example 5) had poor thermal stability, the polymer tended to decompose even when blow molded, and good molded products could not be obtained due to the high Tc. Ta.

Example 3 70% by weight of the polyamide of Example 1 and 30% by weight of glass were melt-kneaded in a 30 mmφ single screw extruder, and the blow moldability was evaluated in the same manner as in Example 1. A molded product with a good appearance was obtained without solidification at the tip of the parison.

Comparative Example 6 An attempt was made to melt and knead 45% by weight of the polyamide of Example 1 and 55% by weight of glass fiber in a 30 mmφ single screw extruder, but the extrusion stability was poor and pellets of good shape could not be obtained.

[0032]

[Table 1]

[0033]

[Effects of the Invention] By using the polyamide resin composition of the present invention, complicated three-dimensional blow molding, which was not possible in the past, has become possible. In addition, heat resistance is significantly improved, and molded products with excellent physical properties such as chemical resistance and low water absorption can be obtained, which can contribute to weight reduction of automobiles and the like.

Claims (4)

[Claims] Claim 1: (a) 50 to 90% by weight of hexamethylene adipamide component, (b) 5 to 40% by weight of hexamethylene terephthalamide component, (c) 4 to 30% by weight of hexamethylene isophthalamide component, (d) Carbon number 6-1
A copolyamide consisting of 1 to 10% by weight of a polyamide component made from a cyclic lactam of 2 and/or an aminocarboxylic acid having 6 to 12 carbon atoms, which has a melting point (Tm),
A crystalline polyamide whose crystallization temperature (Tc) satisfies Tm≧225°C and Tc≦220°C, respectively. 2. Polyamide 50-99 according to claim 1.
A polyamide resin composition containing 1 to 50% by weight of a fibrous reinforcing agent. 3. The polyamide according to claim 1, comprising:
A blow-molded product made of polyamide whose melt viscosity μa (poise), measured at Tm+20°C and a shear rate of 10 (1/sec), satisfies the following: 2,000,000≧μa≧2,000. 4. The polyamide resin composition according to claim 2, at Tm+20° C. and a shear rate of 10 (1/sec).
A blow-molded article using a polyamide resin composition whose melt viscosity μa (poise) as measured by satisfies 2,000,000≧μa≧2,000.