JPS6356904B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyamide composition for profile extrusion molding. Profile extrusion molded products with complex cross-sectional shapes are applied in many fields such as civil engineering, architecture, furniture, and machine parts, and polyvinyl chloride is mainly used as the resin for this purpose. However, although the rheological properties of polyvinyl chloride are suitable for profile extrusion molding, when used alone, the strength and heat resistance of the molded product are inferior, so depending on the application, composite extrusion molding with metal may be performed. There is also. Polyamide is widely used as engineering plastics because of its excellent mechanical properties and heat resistance. However, polyamide not only has a low melt viscosity, but also has a sharp change from melt to solid, making it extremely difficult to extrude polyamide into a profile. That is, in the case of polyamide, the shape retention of the melt is poor when extruded from a irregularly shaped die, and furthermore, it is difficult to control the dimensions with a sizing die, resulting in poor sizing properties. For this reason,
Although polyamide has excellent physical properties, it can only be molded into simple profile extrusion molded products, and the development of applications for polyamide molded products with complex shapes has been delayed. In view of these circumstances, the present inventors have conducted repeated research with the aim of developing a method for stably obtaining polyamide profile extrusion molded products with complex cross-sectional shapes and with high dimensional accuracy. The present invention has been completed by discovering that the object can be achieved by profile extrusion molding using a composition in which specific amounts of a specific inorganic filler and ethylene-based ionomer resin are blended with polyamide. That is, the present invention is a polyamide composition consisting of three components: a high viscosity polyamide with a relative viscosity of 3.0 to 7.0, talc, and an ethylene-based ionomer resin, and the amount of each component is calculated based on the total amount of these three components. In Figure 1 (a triangular coordinate diagram with the apex at 100% weight percentage of each component), the blending ratio expressed in weight percentage is a, the weight percentage of the high viscosity polyamide is a, the weight percentage of talc is b, and the ethylene ionomer. When the weight percentage of the resin is c, point A (a=47, b=50, c=3), B
Point (a=67, b=30, c=3), point C (a=70,
b=10, c=20), point D (a=63, b=10, c=
27) and point E (a=35, b=50, c=15),
The object of the present invention is to provide a polyamide composition that is extremely suitable for profile extrusion molding, and is characterized in that the polyamide composition lies within a range surrounded by straight lines connected in this alpha-beta order. Japanese Patent Publication No. 54-4743 proposes an invention relating to a polyamide composition in which an inorganic filler and an ethylene ionomer resin are blended with polyamide. This invention focuses on improving the impact resistance of polyamide, and with regard to molding processability, only improvement in melt flowability (melt index) is recognized.
A composition for profile extrusion molding needs to have good shape retention and sizing properties of the melt during molding, and if fluidity during melting increases as in the invention, conversely profile extrusion molding becomes difficult. Become. In other words, in the invention, there is no recognition of a polyamide composition suitable for profile extrusion molding, and even more so, as in the present invention, a specific inorganic filler (i.e., talc) and an ethylene-based ionomer resin are added to the high-viscosity polyamide. It is not recognized at all that a composition containing a specific amount of the above is an extremely excellent composition for profile extrusion molding. Specific examples of polyamides used in the present invention include nylon 6, nylon 11, nylon 12
Polylactams such as nylon 66, nylon
610, polyamides obtained from dicarboxylic acids and diamines such as nylon 612, nylon 6/66,
Nylon 6/610, Nylon 6/12, Nylon 6/612, Nylon 6/66/610, Nylon 6/
Examples include copolyamides such as 66/12, nylon 6/6T (T: terephthalic acid component), and mixtures thereof. Among these, nylon 6, nylon 11, nylon 12, nylon 66 and copolymers thereof are particularly useful. In the present invention,
Among these polyamides, the relative viscosity is 3.0~
A high viscosity with a viscosity of 7.0 is used. If the relative viscosity is less than 3.0, the melt will have poor shape retention during extrusion, making stable molding impossible. On the other hand, if polyamide with a relative viscosity higher than 7.0 is used, not only will it require a high load on the screw rotation motor during extrusion molding, but the dispersibility with talc and ethylene-based ionomer resin will be poor, making the composition suitable for profile extrusion molding. I can't get things. Moreover, it is essential that the inorganic filler in the present invention is talc. The shape of the talc to be used is not particularly limited, and may be, for example, plate-shaped, needle-shaped, or fibrous, but plate-shaped is particularly preferred. If something other than talc is used as the inorganic filler, the effects of the present invention cannot be obtained. For example, when inorganic fillers such as calcium carbonate, clay, silica, calcium silicate, wollastonite, and kaolin are used, the shape retention of the melt is poor and the sizing properties are also poor. Furthermore, even when a fibrous reinforcing agent such as glass fiber is used, moldability is poor and the surface of the molded product becomes extremely rough. The ethylene-based ionomer resin used in the present invention is α-olefin containing ethylene and α,β-
It refers to an ionic polymer obtained by adding a metal ion having a valence of 1 to 3 to a copolymer with an unsaturated carboxylic acid derivative. Typical examples of α,β-unsaturated carboxylic acid derivatives include acrylic acid, methacrylic acid, itaconic acid, ethyl acrylate, and methyl methacrylate, and typical examples of metal ions with valences of 1 to 3 include Examples include Na ⁺ , K ⁺ , Zn ⁺⁺ , Al ⁺⁺⁺ , etc. Examples of this ethylene-based ionomer resin include "Corpolen" D580, among various grades commercially available under the trade names "Corpolen" manufactured by Asahi Dow Co., Ltd. and "Himilan" manufactured by Mitsui Polychemical Co., Ltd. “Himilan” 1605, 1706,
It is appropriate to use a grade with a high melt viscosity such as 1855. A feature of the present invention is to provide a polyamide composition for profile extrusion molding, in which a specific amount of talc and a specific amount of ethylene ionomer resin are blended with a high viscosity polyamide. When no ethylene-based ionomer resin is blended, the shape retention of the melt is good, but the sizing properties are poor, the molding is unstable, and the dimensional accuracy of the molded product is not sufficient. Furthermore, if talc is not blended, the shape retention of the melt is poor, making it impossible to obtain a profile extrusion molded product having a complicated cross-sectional shape. The composition of the present invention is made by blending talc and ethylene ionomer resin with a high viscosity polyamide having a relative viscosity of 3.0 to 7.0.
To stably obtain a profile extrusion molded product having a complex cross-sectional shape only when using a composition within the range surrounded by the straight line connecting each point C, D and E in this alphabetical order. Can be done. That is, when a composition within this range is used, both melt retention and sizing properties are good, so a profile extrusion molded product with high dimensional accuracy can be molded extremely stably. The composition range of the present invention shown in FIG. 1 will be explained in detail. First, the blending amount of talc is 10% by weight (linear CD)
The range is from above to 50% by weight (linear AE).
If the blending amount of talc is greater than the above range, the melt viscosity of the composition will be extremely high, resulting in poor moldability and, moreover, the molded product will become brittle. On the other hand, if the blending amount is less than the above range, even if the ethylene-based ionomer resin is blended, the moldability will not be stable and the dimensional accuracy of the molded product will deteriorate. Regarding the amount of ethylene ionomer resin blended, it is necessary that the weight ratio (c/a) of ethylene ionomer resin c to high viscosity polyamide a does not exceed 3/7 (linear DE), and 3% by weight (linear DE). AB) or above. If the amount of the ethylene-based ionomer resin is greater than the above range, not only will the rate of decrease in the tensile strength and heat distortion temperature of the composition increase, but also the swelling of the melt (die swell) will increase when extruded from a irregularly shaped die. This results in poor sizing properties. On the other hand, if the blending amount is less than the above range, the sizing properties of the melt will be poor and the dimensional accuracy of the molded product will be poor. In addition, the composition ratio of the three components in the present invention is from the straight line BC to the apex a
If it is on the side, the sizing property and shape retention of the melt of the composition are poor, and it is impossible to obtain a profile extrusion molded product having a complicated cross-sectional shape. Furthermore, point A' in Figure 1 (a=57, b=40, c=
3), point B (a=67, b=30, c=3), point C' (a
= 65, b = 20, c = 15), point D' (a = 60, b = =
20, c=20) and point E' (a=45, b=40, c=
Polyamide compositions within the range bounded by the straight line connecting 15) in this alphabetical order are particularly useful for profile extrusion molding. In the present invention, the method of blending talc and ethylene ionomer resin with polyamide includes:
There are no particular restrictions, and well-known methods can be used. For example, a melt mixing method using a single-screw or twin-screw extruder can also be employed. Also, prior to mixing the talc with the polyamide, the surface thereof may be treated with a surface treatment agent such as a silane coupling agent. In the present invention, a predetermined amount of talc and a predetermined amount of ethylene ionomer resin are blended into polyamide, but depending on the application, other modifiers such as antistatic materials, ultraviolet absorbers, stabilizers, dyes, pigments, etc. may be added. Agents may also be added. The method of profile extrusion molding of the polyamide composition in the present invention does not particularly require any special equipment, and can be easily carried out using, for example, the same equipment normally used for profile extrusion molding of polyvinyl chloride. Specifically, for example, an extruder, a profile die, a sizing die, a pulling machine, and a cutting machine are installed, and the extrusion temperature is
A molten profile of the desired shape is extruded through a deformed die at 220 to 300°C, passed through a cooled sizing die while applying tension with a pulling machine, and solidified while being corrected to the desired shape.Finally, the desired shape is solidified with a cutting machine. A molded article can be obtained by cutting to length. Next, examples of the present invention and comparative examples will be given.
The relative viscosity of the polyamide used in each example is
It was measured using a 98% sulfuric acid solution according to JIS K 6810-1970. Further, the shape of the talc used in each example was a plate shape. Furthermore, a cross-sectional view of the profile extrusion molded product molded in each example is shown in FIG. In Fig. 2, the wall thickness of the J section is 1.8 mm, and the wall thickness of the K section is 1.5 mm. In addition, in the molded product shown in Figure 2, there is a thin part (H part; standard size, 4.4 mm) and a protrusion (part; standard size, 2.2 mm) where dimensional stability is difficult.
mm) was measured and used as a measure of dimensional accuracy. Examples 1 to 7 and Comparative Examples 1 to 11 Nylon 6 pellets with a relative viscosity of 4.4 [product of Ube Industries, Ltd.; trade name, UBE nylon 1030B],
Talc [product of Hayashi Kasei Co., Ltd.; product name, Micron White S] and ethylene-based ionomer resin pellets [product of Asahi Dow Co., Ltd.; product name, Corporen D580]
The mixture was melt-kneaded in varying amounts using a 30 mm diameter two-shaft two-stage vent extruder (manufactured by Nakatani Kikai Co., Ltd.), and then pelletized. The pellets were extruded through a irregularly shaped die using a 30 mmφ extruder at a set temperature of 240 to 250°C.
The material was passed through a sizing die at a drawing speed of 80 cm/min while applying tension with a drawing machine, corrected and maintained the shape, and cooled and solidified to form a molded product with the cross-sectional shape shown in Figure 2. Table 1 shows the moldability and dimensional accuracy of each example. The evaluation of moldability and dimensional accuracy in Table 1 was based on the following criteria. (1) Evaluation of moldability 〇: Continuous molding is possible △: Molding is possible but unstable ×: Difficult to mold (2) Evaluation of dimensional accuracy 〇: Molded products close to standard dimensions can be obtained. △: Poor dimensional accuracy. ×: A molded product with the desired cross-sectional shape cannot be obtained.

[Table] *: Because it is not possible to maintain the shape of the molten material, it is difficult to pass it through a sizing die.
I couldn't do it.
Example 8 and Comparative Example 12 Instead of using nylon 6 pellets, the relative viscosity was 3.1.
The procedure was the same as in Examples 1 to 7, except that nylon 12 pellets (product name: UBE Nylon 3035B, manufactured by Ube Industries, Ltd.) were used, and the extrusion temperature from the irregular die was changed to 230 to 240°C. By this operation, a molded article having the cross-sectional shape shown in FIG. 2 was molded. The results are shown in Table 2. Note that the evaluation criteria for moldability and dimensional accuracy in Table 2 are the same as above.

[Table] Comparative Example 13 Profile extrusion molding was performed in the same manner as in Example 4, except that nylon 6 pellets with a relative viscosity of 2.9 (product name: UBE Nylon 1015B, manufactured by Ube Industries, Ltd.) were used. However, due to the poor shape retention of the melt,
Molding was not stable. Comparative Example 14 Profile extrusion molding was performed in the same manner as in Example 4, except that kaolin (product of Hayashi Kasei Co., Ltd.; trade name, Satenton No. 1) was used instead of talc, but the melt was Both shape retention and sizing properties were poor, and molding was unstable.

[Brief explanation of the drawing]

FIG. 1 is a triangular coordinate diagram showing the blending ratios of polyamide, talc, and ethylene-based ionomer resin, which are the constituent components of the composition in the present invention.
Moreover, FIG. 2 shows a cross-sectional view of a profile extrusion molded product molded in an example of the present invention and a comparative example.

Claims (1)

[Claims] 1 A polyamide composition consisting of three components: a high viscosity polyamide with a relative viscosity of 3.0 to 7.0, talc and an ethylene ionomer resin, which
In Figure 1 (a triangular coordinate diagram with the apex at 100% weight percentage of each component), the blending ratio, which represents the blending amount of each component as a weight percentage with respect to the total blending amount of the components, is the weight percentage of the high viscosity polyamide. Assuming that a, the weight percentage of talc is b, and the weight percentage of ethylene ionomer resin is c, point A (a = 47, b = 50, c = 3), point B (a = 67, b =
30, c=3), point C (a=70, b=10, c=20),
Point D (a=63, b=10, c=27) and point E (a
= 35, b = 50, c = 15) within a range surrounded by a straight line connecting these in the alphabetical order.