CN106810851B - Glass fiber reinforced PA6 composition with improved floating fiber and preparation method thereof - Google Patents

Abstract

The invention provides a glass fiber reinforced PA6 composition with improved floating fiber and a preparation method thereof, wherein the composition is prepared by mixing, extruding and granulating 30-60 parts of PA6, 1-10 parts of PA66, 25-45 parts of glass fiber, 5-15 parts of mica, 0-5 parts of flexibilizer, 5-10 parts of nucleating agent and 5-10 parts of silicone powder. According to the invention, after the mica and the silicone powder are mixed, the compatibility between the PA6 and the glass fiber is enhanced, and similar anchoring nodes, namely cross-linking points, are formed between the glass fiber and the nylon resin, so that the bonding state of the glass fiber and the resin is improved, and the separation of the glass fiber and the resin is reduced; meanwhile, the nylon 66 also improves the mechanical strength of the composition.

Description

Glass fiber reinforced PA6 composition with improved floating fiber and preparation method thereof

Technical Field

The invention belongs to the field of polymer composite materials, and particularly relates to a glass fiber reinforced PA6 composition with improved floating fiber and a preparation method thereof.

Background

Polyamide (PA, colloquially referred to as nylon) was the first resin developed for fibers by DuPont in the united states and was commercialized in 1939. Polyamides have been developed and produced in the 50 th century to replace metals for the lightweight and cost-effective production of articles in downstream industries. The PA has good comprehensive properties including mechanical property, heat resistance, abrasion resistance, chemical resistance and self-lubricity, and is low in friction coefficient, certain in flame retardance and easy to process.

At present, in order to enhance the toughness of PA and reduce the production cost of PA, proper glass fiber is added into nylon materials to modify the PA materials, but the problem of fiber floating is easy to occur after the glass fiber is added. The phenomenon of fiber floating is generally caused by the exposure of glass fibers, white glass fibers are exposed to the outside in the process of filling the plastic melt into a mold and flowing, and after condensation molding, radial white marks are formed on the surface of a plastic part, and when the plastic part is black, the color difference is increased, so that the phenomenon is more obvious. Therefore, the fiber floating phenomenon not only affects the appearance aesthetic property of the PA part, but also affects the performance of the PA part as a pressure-resistant part.

Disclosure of Invention

The invention aims to provide a glass fiber reinforced PA6 composition with improved floating fiber and a preparation method thereof.

The technical scheme of the invention is as follows:

the invention provides a glass fiber reinforced PA6 composition with improved floating fiber, which is prepared from the following components in parts by weight:

630-60 parts of PA (polyamide),

PA 661-10 parts by weight of a synthetic resin,

25-45 parts of glass fiber,

5-15 parts of mica, namely,

0-5 parts of a toughening agent,

5-10 parts of a nucleating agent,

5-10 parts of silicone powder.

The intrinsic viscosity of the PA6 slice is in the range of 0.6-1.0 dl/g.

The glass fiber is chopped glass fiber, the length of the glass fiber is 2-5mm, and the diameter of the glass fiber is 7-13 microns.

The water content of the mica is less than or equal to 0.1 percent, the oil absorption is less than or equal to 25(g/100g), and the length-diameter ratio is 70.

The toughening agent is selected from one or more of maleic anhydride grafted ethylene-octene copolymer, ethylene-methyl acrylate copolymer or ethylene-methyl acrylate-glycidyl methacrylate;

the nucleating agent is sodium benzoate.

The invention also provides a preparation method of the glass fiber reinforced PA6 composition with the floating fiber improved, which comprises the following steps:

(1) respectively drying PA6 and PA 66;

(2) proportionally adding the dried PA6 and PA66, mica, glass fiber, toughening agent, nucleating agent and silicone powder into a high-speed mixer, and stirring for 3-5 min;

(3) and adding the uniformly mixed materials from a feed inlet of a double-screw extruder, and performing melt extrusion and granulation by the double-screw extruder to prepare the modified glass fiber reinforced PA6 composition.

In the step (1), the PA6 is dried for 4-5h at the temperature of 110-140 ℃; PA66 is dried for 4-5h at the temperature of 110-120 ℃;

in the step (3), the first zone temperature of the double-screw extruder is 220-250 ℃, the second zone temperature is 225-265 ℃, the third zone temperature is 235-275 ℃, the fourth zone temperature is 245-285 ℃, the fifth zone temperature is 240-280 ℃, the sixth zone temperature is 245-285 ℃, the head temperature is 245-285 ℃, and the rotating speed of the host is 15-35 HZ.

Compared with the prior art, the invention has the following beneficial effects:

1. after the mica and the silicone powder are mixed, the compatibility between the PA6 and the glass fiber is enhanced, similar anchoring nodes, namely cross-linking points, are formed between the glass fiber and the nylon resin, the bonding state of the glass fiber and the resin is improved, and the separation of the glass fiber and the resin is reduced.

2. Due to the fact that the thickness of the mechanical action layer between the surface of the glass fiber and the matrix resin is increased, the matrix near the surface of the glass fiber is easier to shear and yield, the absorption and dissipation effects on impact energy are increased, and the toughening effect of the glass fiber on the matrix resin is promoted. Therefore, the glass fiber is well coated in the resin, and the glass fiber and the resin flow synchronously in the processing process and are not easy to tear apart, thereby greatly reducing the exposure of the glass fiber.

3. The mica and the silicone powder reduce the exposure of the glass fibers, so that the friction between the glass fibers and the screw rod is correspondingly reduced, the torque of the screw rod is reduced, and the screw rod is easy to process.

4. PA66 has a higher melting point, and can maintain stronger strength and rigidity at higher temperature, so the PA66 is added in the invention to improve the mechanical strength of the PA6 composition.

5. The modified glass fiber reinforced PA6 composition prepared by the invention has excellent mechanical properties.

Detailed Description

The present invention will be further described with reference to the following examples.

The mechanical property test method comprises the following steps:

the composition prepared by the invention is injected and molded into a test sample at the temperature of 230-270 ℃ by using a plastic injection molding machine according to the GB standard, and the dimensions (length multiplied by width multiplied by thickness) of the test sample are as follows: tensile bars (dumbbell type), 170.0 × 10.0 × 4.0; curved splines, 80.0 × 10.0 × 4.0; unnotched impact specimen, 80.0 × 10.0 × 4.0; notched impact bar, 80.0X 10.0X 4.0, V notch, notch depth 1/5.

After the test specimens were molded, the specimens were placed in a standard environment at 23. + -. 2 ℃ and 50. + -. 5% humidity for 16 hours and then tested under the conditions of 23. + -. 2 ℃ and 50. + -. 5% humidity.

Tensile strength and elongation at break: the tensile rate was 5mm/min, as measured in GB 1040.

Flexural strength and flexural modulus: the bending speed was 1.25mm/min, measured according to GB 9341.

Impact strength of the simply supported beam notch: testing according to GB 1043.

The starting materials used in the examples below: the intrinsic viscosity of the PA6 slice is in the range of 0.6-1.0 dl/g;

the glass fiber is chopped glass fiber, the length of the glass fiber is 2-5mm, and the diameter of the glass fiber is 7-13 microns;

the water content of the mica is less than or equal to 0.1 percent, the oil absorption is less than or equal to 25(g/100g), and the length-diameter ratio is 70.

Example 1

(1) Drying PA6 at 110 ℃ for 4 h; PA66 is dried for 4 hours at the temperature of 110 ℃;

(2) weighing 60 parts of dried PA6, 1 part of PA66, 25 parts of glass fiber, 5 parts of mica, 5 parts of sodium benzoate and 5 parts of silicone powder;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 3 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 230 ℃, the temperature of a second zone is 245 ℃, the temperature of a third zone is 255 ℃, the temperature of a fourth zone is 265 ℃, the temperature of a fifth zone is 260 ℃, the temperature of a sixth zone is 265 ℃, the temperature of a machine head is 265 ℃, and the rotating speed of a main machine is 15 HZ. The results of the performance tests are shown in Table 1.

Example 2

(1) Drying PA6 at 110 ℃ for 4 h; PA66 is dried for 4 hours at the temperature of 110 ℃;

(2) weighing 40 parts of dried PA6, 10 parts of PA66, 30 parts of glass fiber, 5 parts of mica, 5 parts of toughening agent (ethylene-methyl acrylate copolymer and ethylene-methyl acrylate-glycidyl methacrylate are in a ratio of 1: 1), 5 parts of sodium benzoate and 5 parts of silicone powder;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 3 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 220 ℃, the temperature of a second zone is 225 ℃, the temperature of a third zone is 235 ℃, the temperature of a fourth zone is 245 ℃, the temperature of a fifth zone is 240 ℃, the temperature of a sixth zone is 245 ℃, the temperature of a machine head is 245 ℃, and the rotating speed of a main machine is 15 HZ. The results of the performance tests are shown in Table 1.

Example 3

(1) Drying PA6 at 140 deg.C for 4-5 h; PA66 is dried for 5 hours at the temperature of 120 ℃;

(2) weighing 40 parts of dried PA6, 5 parts of PA66, 35 parts of glass fiber, 10 parts of mica, 3 parts of toughening agent (maleic anhydride grafted ethylene-octene copolymer), 5 parts of sodium benzoate and 10 parts of silicone powder;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 3 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 240 ℃, the temperature of a second zone is 255 ℃, the temperature of a third zone is 265 ℃, the temperature of a fourth zone is 275 ℃, the temperature of a fifth zone is 270 ℃, the temperature of a sixth zone is 275 ℃, the temperature of a machine head is 275 ℃, and the rotating speed of a main machine is 35 HZ. The results of the performance tests are shown in Table 1.

Example 4

(1) Drying PA6 at 120 deg.C for 5 h; PA66 is dried for 5 hours at the temperature of 120 ℃;

(2) weighing 30 parts of dried PA6, 5 parts of PA66, 45 parts of glass fiber, 15 parts of mica, 10 parts of sodium benzoate and 5 parts of silicone powder;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 5 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 250 ℃, the temperature of a second zone is 265 ℃, the temperature of a third zone is 275 ℃, the temperature of a fourth zone is 285 ℃, the temperature of a fifth zone is 280 ℃, the temperature of a sixth zone is 285 ℃, the temperature of a machine head is 285 ℃, and the rotating speed of a main machine is 35 HZ. The results of the performance tests are shown in Table 1.

Comparative example 1

(1) Drying PA6 at 110 ℃ for 4 h; PA66 is dried for 4 hours at the temperature of 110 ℃;

(2) weighing 50 parts of dried PA6, 5 parts of PA66, 35 parts of glass fiber, 5 parts of toughening agent (maleic anhydride grafted ethylene-octene copolymer) and 5 parts of sodium benzoate;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 3 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 220 ℃, the temperature of a second zone is 225 ℃, the temperature of a third zone is 235 ℃, the temperature of a fourth zone is 245 ℃, the temperature of a fifth zone is 240 ℃, the temperature of a sixth zone is 245 ℃, the temperature of a machine head is 245 ℃, and the rotating speed of a main machine is 35 HZ. The results of the performance tests are shown in Table 1.

Comparative example 2

(1) Drying PA6 at 140 ℃ for 5 h; PA66 is dried for 5 hours at the temperature of 120 ℃;

(2) weighing 40 parts of dried PA6, 5 parts of PA66, 35 parts of glass fiber, 10 parts of calcium sulfate mica, 5 parts of a toughening agent (maleic anhydride grafted ethylene-octene copolymer) and 5 parts of sodium benzoate;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 5 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 220 ℃, the temperature of a second zone is 225 ℃, the temperature of a third zone is 235 ℃, the temperature of a fourth zone is 245 ℃, the temperature of a fifth zone is 240 ℃, the temperature of a sixth zone is 245 ℃, the temperature of a machine head is 245 ℃, and the rotating speed of a main machine is 35 HZ. The results of the performance tests are shown in Table 1.

Comparative example 3

(1) Drying PA6 at 120 deg.C for 5 h; PA66 is dried for 5 hours at the temperature of 120 ℃;

(2) weighing 40 parts of dried PA6, 5 parts of PA66, 35 parts of glass fiber, 5 parts of toughening agent (maleic anhydride grafted ethylene-octene copolymer) and 5 parts of sodium benzoate;

(3) stirring the materials weighed in the step (2) in a high-speed mixer for 5 min;

(4) then adding the uniformly mixed materials into a feed inlet of a double-screw extruder;

(5) melting and extruding the materials by a double-screw extruder, and granulating;

the processing technology of the double-screw extruder comprises the following steps: the temperature of a first zone of the double-screw extruder is 220 ℃, the temperature of a second zone is 225 ℃, the temperature of a third zone is 235 ℃, the temperature of a fourth zone is 245 ℃, the temperature of a fifth zone is 240 ℃, the temperature of a sixth zone is 245 ℃, the temperature of a machine head is 245 ℃, and the rotating speed of a main machine is 35 HZ. The results of the performance tests are shown in Table 1.

TABLE 1

Performance of	Test method	Unit of	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2	Comparative example 3
										Bending strength	GB 9341	MPa	192	203	210	210	170	172	176
Flexural modulus	GB 9341	MPa	7535	8501	9511	10632	7100	7700	7230
										Tensile strength	GB 1040	MPa	141	147	145	173	125	124	132
Elongation at break	GB 1040	%	18	18	21	22	5	4	4
										Impact strength of simply supported beam notch	GB 1043	KJ/m2	37	37	35	32	11	12	12
Surface of the article			Bright and has no floating fiber	Bright and has no floating fiber	Bright and has no floating fiber	Bright and has no floating fiber	With floating fibres	With floating fibres	With floating fibres

As can be seen from the comparison between the examples and the comparative examples in the above Table 1, the glass fiber reinforced PA composition prepared by the invention has the similar flexural strength as the comparative examples, but the flexural modulus, the tensile strength, the elongation at break and the impact strength of the notch of the simple beam are all obviously higher than those of the materials prepared by the comparative examples, and the surface of the part is bright and has no floating fiber. The compatibility between the PA6 and the glass fiber is enhanced after the mica and the silicone powder are mixed, and similar anchoring nodes, namely cross-linking points, are formed between the glass fiber and the nylon resin, so that the bonding state of the glass fiber and the resin is improved, and the separation of the glass fiber and the resin is reduced; meanwhile, the nylon 66 also improves the mechanical strength of the composition.

The embodiments described above are intended to facilitate one of ordinary skill in the art in understanding and using the present invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the embodiments described herein, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims (7)

1. The glass fiber reinforced PA6 composition with the floating fiber improved is prepared from the following components in parts by weight:

630-60 parts of PA (polyamide),

PA 661-10 parts by weight of a synthetic resin,

25-45 parts of glass fiber,

5-15 parts of mica, namely,

0-5 parts of a toughening agent,

5-10 parts of a nucleating agent,

5-10 parts of silicone powder,

the intrinsic viscosity of the PA6 slice is in the range of 0.6-1.0 dl/g.

2. The glass fiber reinforced PA6 composition with improved blooming, as claimed in claim 1, wherein: the glass fiber is chopped glass fiber, the length of the chopped glass fiber is 2-5mm, and the diameter of the chopped glass fiber is 7-13 microns.

3. The glass fiber reinforced PA6 composition with improved blooming, as claimed in claim 1, wherein: the mica water content is less than or equal to 0.1 percent, the oil absorption is less than or equal to 25(g/100g), and the length-diameter ratio is 70.

4. The glass fiber reinforced PA6 composition with improved blooming, as claimed in claim 1, wherein: the toughening agent is selected from one or more of maleic anhydride grafted ethylene-octene copolymer, ethylene-methyl acrylate copolymer or ethylene-methyl acrylate-glycidyl methacrylate.

5. The glass fiber reinforced PA6 composition with improved blooming, as claimed in claim 1, wherein: the nucleating agent is sodium benzoate.

6. A process for preparing a glass fiber reinforced PA6 composition according to claim 1, wherein: the method comprises the following steps:

(1) respectively drying PA6 and PA 66;

(2) proportionally adding the dried PA6 and PA66, mica, glass fiber, toughening agent, nucleating agent and silicone powder into a high-speed mixer, and stirring for 3-5 min;

(3) and adding the uniformly mixed materials from a feed inlet of a double-screw extruder, and performing melt extrusion and granulation by the double-screw extruder to prepare the modified glass fiber reinforced PA6 composition.

7. The method of claim 6, wherein: in the step (1), the PA6 is dried for 4-5h at the temperature of 110-140 ℃; PA66 is dried for 4-5h at the temperature of 110-120 ℃;

in the step (3), the first zone temperature of the double-screw extruder is 220-250 ℃, the second zone temperature is 225-265 ℃, the third zone temperature is 235-275 ℃, the fourth zone temperature is 245-285 ℃, the fifth zone temperature is 240-280 ℃, the sixth zone temperature is 245-285 ℃, the head temperature is 245-285 ℃, and the rotating speed of the host is 15-35 HZ.