JPH04149234A - Polyamide, its resin composition and blow molded product thereof - Google Patents

Abstract

PURPOSE:To obtain a polyamide, composed of a hexamethylene adipamide component, a hexamethylene terephthalamide component and a hexamethylene isophthalamide component, having specific melting point and crystallization temperature and excellent in resistance to heat and antifreezing agents for roads, dimensional stability, etc. CONSTITUTION:The objective crystalline polyamide is composed of (A) 50-90wt.% hexamethylene adipamide component, (B) 5-40wt.% hexamethylene terephthalamide component and (C) 5-30wt.% hexamethylene isophthalamide component. The aforementioned polyamide has >=225 deg.C melting point (Tm) and <=220 deg.C crystallization temperature (Tc). Furthermore, 99-50wt.% aforementioned polyamide is blended with 1-50wt.% fibrous reinforcing agent to afford the objective composition having 2000000-2000 P melt viscosity measured at (Tm+20 deg.C) and 10(sec<-1>) shearing rate. The resultant composition is further blow molded to provide the objective molded product.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a polyamide resin composition with excellent heat resistance, chemical resistance, road antifreeze properties, low water absorption, and dimensional stability; The present invention relates to blow molded products used for mechanical parts and automobile parts using the composition.

(Prior Art) Polyamide resins are widely used as engineering plastics due to their excellent physical properties. In particular, with the recent weight reduction of automobiles, there is a desire for polyamide resins with well-balanced physical properties such as heat resistance, chemical resistance, road antifreeze resistance, low water absorption, and dimensional stability.

In order to obtain a polyamide resin with well-balanced physical properties as described above, the present inventors used (a) a hexamethylene adipamide component (hereinafter abbreviated as 66) and (b) a hexamethylene terephthalamide component (hereinafter referred to as 6T). A detailed study was conducted on a polyamide consisting of (c) hexamethylene isophthalamide component (hereinafter abbreviated as 6). 66.6T
, 6I as a component is known.
A copolyamide containing 1.5% by weight of the 6I component, 48.5-60% by weight of the 6I component, and 0-10% by weight of the 6N component is shown.

Polyamides in this composition range have very poor thermal stability, and the properties of molded products tend to fluctuate, making it difficult to obtain reproducibility.
Although polyamide in this composition range is crystalline, T
c exceeds 220°C, making it impossible to solidify the parison quickly in three-dimensional blow molding. 66.6T and 6I polyamides as blow molding materials are disclosed in JP-A-63-94842 and JP-A-63-1206.
45, JP-A-176555, and the like. These known examples commonly describe polycaprolactam (hereinafter simply abbreviated as 6) or a copolymerized polyamide consisting of aliphatic polyamide/6T and/6I components as the polyamide. That is, specifically 6
Component 15% by weight, 6I component 28.3% by weight, 6I component 5
6.7% by weight of polyamide is shown.

The polyamide in this composition was a non-quality polyamide according to the experiments conducted by the present inventors, and did not have the physical properties intended by the present inventors. In other words, since it is of inferior quality, it has particularly poor chemical resistance, and it is not possible to obtain a material that is well-balanced in terms of physical properties such as heat resistance and rigidity. Also 66, /
There is also no description of polyamides consisting of 6T/61 components.

Therefore, the reality is that a 66/6T/6I polyamide material with well-balanced physical properties has not been obtained.

In addition, as polyamide-based glass blow molding materials, materials such as nylon 6.66 and materials made by adding impact-resistance improving side and reinforcement to nylon 6.66 are widely known (Japanese Patent Publication No. 55-41659). ), however, even if one attempts to obtain a three-dimensional blow-molded product with a relatively long parison length using these materials, the appearance of the molded product may be poor, the heat resistance may be poor, or even if the heat resistance is good, crystallization may occur. Due to the high temperature, the parison solidifies quickly, making it impossible to obtain a long parison, and the material is not sufficiently satisfactory for obtaining three-dimensional blow-molded products.

(Problems to be Solved by the Invention) However, in recent years, along with the weight reduction of automobile parts, the current situation is that the required characteristics for resin molded products that replace metals have become even more severe.

Particularly in the engine compartment and directly connected parts to the engine, such as resonators, air spoilers, air inlet tubes, duct air intakes, intake manifolds, water pipes, radiator tanks, etc. Heat resistance - Recommended product resistance - Low water absorption. Materials with well-balanced physical properties such as road antifreeze resistance and dimensional stability are required. In making these resins, we need materials that not only have the above-mentioned balance of physical properties but also can be three-dimensionally blow molded into complex shapes, that is, materials that have improved drawdown properties, can easily form long parisons, and have a good surface appearance. Must.

Therefore, the present inventors conducted a more detailed study on the above-mentioned 66.6T and 6I polyamides, and found that by limiting the composition of each to a specific range and setting Tm and Tc at appropriate temperatures. The inventors of the present invention have discovered that it is possible to easily obtain a relatively long parison with well-balanced physical properties and to prepare a polyamide resin material that can be three-dimensionally blow molded.

(Means for Solving the Problems) That is, the present invention includes (1) (a) 50 to 90% by weight of the 66 component, (b) 5 to 40% by weight of the 6I component, and (c) 5 to 301% of the 6I component! % of crystalline polyamide, characterized in that its melting point (Tm) and crystallization temperature (Tc) satisfy Tm5225°C Tc≦220'C, (2
) A polyamide resin composition comprising 99 to 50% by weight of the above polyamide and 1 to 50% by weight of a fibrous reinforcing agent, (3) (a) 50 to 90% by weight of 66 component, (b) 5 to 40% by weight of 6I component, (c) Polyamide consisting of 5 to 30% by weight of 61 components, Tm, Tc and Tm + 20°C
, melt viscosity μ measured at a shear rate of 10 (sec-1)
m. (Poise) or a blow-molded product obtained by blow-molding a crystalline polyamide satisfying the following: Tm5225°C Tc6220°C 2000000≧μ61°≧2000, and (4) the polyamide resin composition of (2) above, which has a Tm
-1-2 The melt viscosity μa10 (poise) measured at Q'C shear IQ (sec-1>) is 2.000,000
≧μ1. . A blow-molded product is provided by blow-molding a polyamide resin composition that satisfies ≧2,000.

In other words, the feature of the present invention is that by specifying the composition of each polyamide component, the melting point, crystallization temperature, and melt viscosity of the polyamide can be adjusted to 1/2, thereby making it possible to prepare a material with well-balanced physical properties. Furthermore, it has been found that the present material is a crystalline polyamide resin composition material that can easily be formed into a long parison by blow molding, and is particularly suitable for three-dimensional blow molding.

The present invention will be described in detail below.

The polyamide that can be used in the present invention is (a>66
component 50-90% by weight, (b) 6I component 5-40% by weight
, (c) A polyamide prepared within the composition range of 5 to 30% by weight of the 61 component. 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 exceed 220°C and the blowing This is not preferable because it becomes impossible to obtain a sufficiently long parison during molding. If the 6I component is less than 5% by weight, the melting point of the resulting polyamide will be lower than 225°C, resulting in decreased heat resistance and unbalanced physical properties; if it exceeds 40% by weight, although the heat resistance will improve, crystallization will occur. The temperature exceeds 220°C, which is undesirable because it causes the parison to solidify during blow molding. Furthermore, if the 6I component is less than 5% by weight, it will essentially become a 66/6T copolymer, and although the heat resistance will improve, the crystallization temperature will also exceed 220°C, which will accelerate the solidification of the parison during blow molding. 61 when exceeding
If the ingredients are unqualified, the melting point will be lowered, and the crystallinity and heat resistance will be lowered. That is, the polyamide of the present invention is nylon 6
It is based on the design idea that the crystallization temperature of 6 is lowered by introducing the 61 component to improve blow moldability, and the decrease in heat resistance due to the addition of the 6I component is compensated for by the addition of the 6I component. A blow moldable polyamide with well-balanced physical properties cannot be obtained without such a design concept. Furthermore, in order to obtain a polyamide that satisfies the conditions of Tm 5225°C and Tc 6220°C, a polymerization test was conducted one by one within the above composition range of the 66.6T and 6I components, and the 'rm, Tc, and crystallinity of the obtained polyamide were differentially scanned. The determination was made by measuring with a calorimeter (DSC).

The blow moldability of the obtained polyamide material was Tm+20℃1
Melt viscosity μa+ at shear rate to (sec-1)
o (poise) was measured using a melt indexer manufactured according to ASTM-D-1238. Blow moldability and parison condition were evaluated by molding with a blow molding machine.

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 each component may be charged into the polymerization kettle in the form of 66.6T and 6I salts, or in the form of their respective monomers.

The degree of polymerization of the polyamide used here is not particularly limited, but from the viewpoint of the dischargeability of the polyamide from the polymerization pot, the relative viscosity (1 g of polymer is dissolved in 1.0 ml of 98% drifting acid and C-measured at 25°C. It is desirable to use a polyamide in which the value (same) is in the range of 15 or more and less than 5.

A preferred embodiment also includes further performing solid phase polymerization after the melting process to obtain a desired melt viscosity.

In the same phase polymerization, a phosphorus compound or the like may be added before promoting polymerization. As the phosphorus compound, phosphoric acid, phosphorous acid, hypophosphorous acid, birophosphoric acid, polyphosphoric acid, and their alkaline earth metal salts can be effectively used. In particular, phosphoric acid is commonly used.

The amount of the phosphorus compound added is not particularly limited, but is preferably 0.01 to 5%, more preferably 0.05 to 2%.
%. 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 an aqueous solution of a phosphorus compound to pellets, powder, and pieces of polyamide resin,
8. A mixing method using a Schillermi A mixer, tumbler, ribbon mixer, etc. is preferably used. In addition to the method of adjusting the melt viscosity and L'C field phase polymerization, it is also possible to melt and cross-wire the polyamide resin to which the above phosphorus compound has been added.
1 ability. A known extruder can be used for melt-kneading.

The melting point of the polyamide used here is preferably 225°C or higher; if the melting point is lower than 225°C, sufficient heat resistance cannot be obtained.

There is no particular upper limit to the melting point, but from the viewpoint of operability during polymerization and moldability during molding, a value of 300'C or less is appropriate.

It is effective for the crystallization temperature to be 220° C. or lower in order to obtain a relatively long parison. If the temperature is higher than 220"C, the parison solidifies quickly and it becomes impossible to obtain the desired parison length. There are no particular restrictions on the crystallization temperature, but crystallization can generally be performed at room temperature. It's true that the temperature is about 40 degrees Celsius.

There is no particular limit to the degree of crystallinity, and any polyamide within the composition range of the present invention can be used without any problems with crystallinity.

T m, +-20℃ 1 shear rate 10 (sec-1,
) Melt viscosity μ4. . (Poise) is 2, oo
o, ooo≧μalo≧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.

Examples of fibrous reinforcing agents that can be used in the present invention include aramid fibers, polyamide fibers, glass fibers, carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, zirconia fibers, and potassium titanate whiskers. Glass fiber, carbon fiber, etc. are preferably used. These fibrous reinforcing agents can be used untreated or with thermally stable silane camping agents such as triethoxygamma-amitsunorovirdyrane, N-β(aminoethyl)-γ-aminopropyltrimethoxy. Those surface-treated with dylan, vinyl 1-ethoxysilane, γ-crisidoxib+7-viltrimethoxysilane, etc. are preferred, and it is also possible to use two or more of these fibrous reinforcing agents. In addition to the fibrous reinforcement, the so-called! ! Organic fillers, such as talc, kaolin, stone, mica, quartz, calcium carbonate, magnesium hydroxide, calcium phosphate, titanium phosphate, sericite, anhydrous mica, wollastonite, white clay, white carbon,
Capon black, zinc powder, etc. can be added.

The polyamide resin composition of the present invention preferably includes 99 to 50% by weight of polyamide and 1 to 50% by weight of fibrous reinforcing agent. . ,
Particularly preferably, the material is composed of 1% polyamide 95 to 55 fibers and 5 to 45% by weight fibrous reinforcing agent.If the amount of reinforcing agent exceeds 50% by weight, the characteristics of polyamide will not be exhibited. This is not desirable because it differs from the original purpose. On the other hand, if the amount of indigo in the fibrous reinforcing agent is less than 1% by weight, the effect of the reinforcing agent will not be exhibited and the purpose of obtaining a reinforced polyamide molded article will not be achieved.

The method of mixing the polyamide resin and the fibrous reinforcing agent is not particularly limited, and a commonly known method can be employed. For example, polyamide resin pellets, powders, strips, etc. and fibrous reinforcing agents are uniformly mixed in a known mixer (Heshisiel mixer, tumbler, ribbon mixer, etc.) and then melted in an extruder with sufficient mixing capacity. A suitable method is to knead the polyamide resin composition and then blow mold it. In blow molding, it is also possible to use an extruder or the like in advance to knead the mixture, melt and knead it directly in the molding machine without forming it, and then mold it.

Mixed glue of polyamide and fibrous reinforcing agent, which is the raw material for obtaining the blow-molded product of the present invention, is mixed at m-t-20°C,
Melt viscosity μ measured at shear rate 1.0 (sec-1)
a10 (Poise) Rikishaku 2, 000. 000≧μm,. ≧2. It must be within the range of 000.

When the polyamide composition, which is the raw material for obtaining the blow molded product of the present invention, is molded using a blow molding machine equipped with an accumulator, when the polyamide is kept in a high temperature molten state for a long time, the heat resistance stability of the polyamide It is useful to add a heat resistant agent for this purpose. 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 usually 0.005 to 100 parts by weight of polyamide.
The amount is preferably 0.05 parts by weight, more preferably 0.001 to 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 alkali halide added is usually 0.05 to 1 part by weight, more preferably 0.1 to 0.5 part by weight, per 100 parts by weight of the polyamide.

In addition, as other #4 heat agents, antioxidants or commercially available antioxidant phenol compounds, phosphite compounds, thioether compounds, etc. can be suitably used.

These antioxidants and oxidation stage 1F agents can be used in combination of one or more kinds. The amount added is usually 0.01 to 5 parts by weight, more preferably 0.05 to 2 parts by weight, per 100 parts by weight of polyamide.

The blow-molded product of the present invention may contain other components, such as polyamide components other than the present invention, to the extent that its moldability and physical properties are not impaired.
It is possible to add impact modifiers, pigments, lubricants, mold release agents, seedlings, nucleating agents, etc.

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.

Examples 1 to 2, Comparative Example 1 Component 66, component 6T, and component 6I were prepared into the compositions shown in Table 1 and put into a polymerization pot to obtain pellets of solution polymerized I to copolyamide. The properties of this copolyamide were as shown in Table 1. It shows well-balanced physical properties compared to nylon 66, especially Tc is lower than nylon 66 at 23℃~43℃.
The material has a low temperature and is suitable for two-dimensional blow molding, and its water absorption properties are also significantly reduced.

Table Comparative Examples 2 to 4 Component 66, component 6T, and component 6I were prepared to have the compositions shown in Table 2, and put into a polymerization kettle and subjected to solution polymerization to obtain a copolyamide pellet. The properties of this copolyamide were as shown in Table 2.6 With a composition outside the composition range of the present invention, it was not possible to obtain a polyamide satisfying the conditions of the present invention. In particular, Comparative Example 2 has Tm=210°C and nylon 6 (Tm=2
(25°C), and its heat resistance is inferior to nylon 6.

In addition, since the crystallinity has decreased, chemical resistance has also been lost, and the purpose of using the 66/6T/6I system has been lost.

Examples 3-4. Comparative Example 5 Examples 1-2. 70% by weight of the polyamide obtained in Comparative Example 1 was mixed with 30% by weight of glass fibers, melted and kneaded using an extruder with a diameter of 30 mm, and then pelletized. After drying this pellet in vacuum, a test piece was molded and the physical properties were measured, and the results shown in Table 3 were obtained. All of the materials had well-balanced physical properties, and in particular, the Tc was sufficiently lower than that of Comparative Example 2, and materials suitable for use as three-dimensional blow molding materials were prepared.

Table 3 Examples 5 to 6, Comparative Examples Examples 1 to 2, and Comparative Example 1 The polyamide pellets obtained in Examples 1 to 2 and Comparative Example 1 were solid-phase polymerized to form polyamides with melt viscosity characteristics shown in Table 4. This pellet was formed into a parison with an outer diameter of 20 mm and a wall thickness of 4 mm using a blow molding machine with an extruder having a diameter of 40 mmφ, and was molded into a complex-shaped vibrator with an outer diameter of 50 mm and a length of 1000 mm using a three-dimensional blow mold. . With the materials of Examples 5 and 6, there was no solidification at the tip of the parison, and a molded product with a good appearance and conforming to the mold dimensions was obtained.

On the other hand, in the case of nylon 66 (Comparative Example 6), the tip of the parison was not molded to the shape according to the mold dimensions, and it seems that the tip of the parison solidified early and did not expand sufficiently. The results are shown in Table 4.

Table Comparative Examples 7 to 9 The polyamide pellets obtained in Comparative Examples 2 to 4 were solid-phase polymerized to thicken them into polyamides with melt viscosity characteristics shown in Table 5.The pellets were then extruded into a 40 mm diameter extruder. A parison with an outer diameter of 20 mm and a wall thickness of 4 mm was formed using a blow molding machine, and a parison with an outer diameter of 50 mm was formed using a three-dimensional blow molding mold.
It was molded into a complex-shaped pipe with a length of 1000 mm. In Comparative Example 7, the drawdown of the parison was severe and a molded product with uniform thickness could not be obtained. In Comparative Examples 8 and 9, the tip of the parison was not molded to the shape according to the mold dimensions, and it seems that the tip of the parison solidified early and did not expand sufficiently.

In particular, in Comparative Example 9, thermal decomposition of the polymer occurred, gas was generated from the surface of the parison, and the surface appearance of the obtained molded product was also poor. The results are shown in Table 5.

Table Examples 7 to 8, Comparative Examples 10 to 12 30 m
The mixture was melt-kneaded using an m-diameter extruder and then formed into pellets. After vacuum drying this pellet, the melt viscosity was measured and Table 6
The material shown in was obtained. This pellet was made into a diameter of 40 m.
Using a blow molding machine with mφ extruder, the outer diameter is 20 mm.
A parison having a diameter of 4 mm and a wall thickness of 4 mm was formed and molded into a complex-shaped pipe with an outer diameter of 50 nm and a length of 1000 mm using a three-dimensional blow molding mold. In the materials of Examples 7 and 8, there was no solidification at the tip of the parison, and a molded product with good appearance and conforming to the mold dimensions was obtained, but in the materials of Comparative Examples 10, 11, and 12, the tip of the parison did not expand sufficiently. It seems that the tip of the parison solidified at an early stage. The results are shown in Table 6.

Table Example 9 Iodination @ 0.0311 parts per 100 parts by weight of the polyamide of Example 5. and 0.4 parts by weight of potassium iodide were added and mixed in a 30+n, nn diameter extruder set at 280°C. After vacuum drying this pellet, 280″C1 shear rate 10 s
When the melt viscosity was measured at e c -1, jl a,
t.

It was 103,000 poise. Next, this pellet was molded at 280°C using a molding machine with a diameter of 40 m and an extruder equipped with an accumulator to an external diameter of 20 m rri.
, A parison with a wall thickness of 4 mm was formed, and 20 pipes with a complex shape with an outer diameter of 50 nm and a length of 550 mm were successively formed in a −=dimensional blow mold. A molded product with a good appearance was obtained without solidification at the tip of the parison.

For comparison, the above blow molding was carried out in the same manner without adding a heat resistant agent to the polyamide of ρ15, and the result was 10
From the time the pipe was finished forming, a slight amount of gas was observed to be generated from the surface of the pipe.

Example 10 ij teramide 80 weight of Example 5? mini glass fiber 2
0 weight? (-) and added and mixed 0.03 parts of fI of iodide and 0.4 parts of potassium iodide to 10 parts by weight of this composition Th, and after melt-kneading in an extruder with a diameter of 30 mm set at 280°C. After vacuum drying, the melt viscosity was measured at 280°C and a shear rate of IQsec-1, and it was found to be μmlo = 210.00.
It's 0 poise 7'j. Next, this Peshisoto is 40m in diameter.
Using a blow molding machine with an accumulator and an extruder of mφ, it was molded at 280°C with an outer diameter of 20 nm and a thickness of FF' 4.
(7) Parison] was formed, and 20 complex-shaped pipes with an outer diameter of 50 mm and a length of 550 mm were successively molded into a mold for dimensional blow molding. A molded product with a good appearance was obtained without solidification at the tip of the parison.

(Invention, 7) Effect W) It is now possible to create yaw-dimensional blow molded products with complex shapes, which could not be obtained with conventional heat-resistant materials, in a specific composition range consisting of 66.6T and 6T components. It can contribute to energy saving.

It has great commercial value.

Claims (4)

[Claims] (1) (a) Hexamethylene adipamide component 50-90
Weight %, (b) hexamethylene terephthalamide component 5~
40% by weight, (c) hexamethylene isophthalamide component 5 to 30% by weight, and has a melting point (T
m) A crystalline polyamide characterized in that its crystallization temperature (Tc) satisfies Tm≧225°C and Tc≦220°C, respectively. (2) 99 to 50% by weight of the polyamide according to claim (1)
and a polyamide resin composition containing 1 to 50% by weight of a fibrous reinforcing agent. (3) The polyamide according to claim (1), wherein Tm+
Melt viscosity μ_a_1_0 (poise) measured at 20°C and shear rate of 10 (sec-1) is 2,000,000≧
A blow-molded product made of polyamide that satisfies μ_a_1_0≧2,000. (4) The polyamide resin composition according to claim (2), which has a melt viscosity μ_a_1_0 (poise) of 2,000 when measured at Tm+20°C and a shear rate of 10 (sec-1),
A blow-molded product obtained by blow-molding a polyamide resin composition satisfying 000≧μ_a_1_0≧2,000.