CN102677217B - Modified POM (polyoxymethylene) fiber and preparation method thereof - Google Patents

Abstract

A kind of modified POM fiber of the present invention and preparation method thereof firstly use nano-calcium carbonate to modify POM, adopt the method for blending and enveloping to prepare nano-CaCO ₃ /POM composite material, it is to mix nano-CaCO ₃ with POM after modification , and then the mixture is extruded with a twin-screw, pelletized, dried after pelletizing, and then spun. The blending and encapsulation method of the present invention makes the nano- _CaCO3 particles stick to the softened POM, saves the steps of twin-screw extrusion and granulation, has simple operation process and low cost, and overcomes many problems of existing blending defect. Secondly, the market price of nano-calcium carbonate is low, and the modification effect on resin is good. Thirdly, the melt-spinning method has simple process, high production efficiency, and is easy to realize industrialized production. Finally, compared with water bath stretching, hot air bath stretching can be stretched at a temperature above 100°C, improving the stretching conditions and obtaining fibers with better properties.

Description

A kind of modified POM fiber and preparation method thereof

technical field

The invention relates to a modified POM fiber and a preparation method thereof, in particular to a nano _CaCO3 modified POM fiber and a preparation method thereof.

Background technique

Polyoxymethylene (POM) fiber has high strength, high modulus, excellent dimensional stability, alkali resistance, chemical corrosion resistance, light resistance, weather resistance and other properties. It is one of the synthetic fibers with the best comprehensive properties. With the development of the economy and the improvement of the industrial level, the application fields of polyoxymethylene materials are expanding day by day due to their good comprehensive properties. The consumption of polyoxymethylene products is also growing rapidly, but for a long time, the development of polyoxymethylene in my country has been relatively backward. There is almost no polyoxymethylene fiber, and proprietary materials have always relied on imports. Therefore, it is a long way to go to carry out research on polyoxymethylene. And because of its outstanding comprehensive properties, it is urgently hoped that polyoxymethylene can be made into fibers to meet different needs. Therefore, we should vigorously strengthen the research and development of polyoxymethylene fiber, find out a suitable process route, prepare functional and high-performance products, and broaden its application fields. There is an urgent realistic demand.

Although POM has superior comprehensive performance, it has shortcomings such as insufficient thermal stability and toughness of POM. In order to improve the performance of polyoxymethylene and improve its application field, it is very important to modify polyoxymethylene. For a long time, people have been blending and modifying POM by means of elastomer toughening and non-elastomer toughening, and some research results have been obtained. However, elastomer toughened POM is at the expense of other mechanical properties of POM. Even for thermoplastic polyurethane (TPU), which is currently recognized as having the best compatibility with POM, its addition amount must not be less than 35% to make the blended material There is an obvious brittle-ductile transition, adding a large amount of TPU not only reduces the strength of the material, but also increases the cost of the product.

Since the concept of nanocomposites was first proposed in 1984, nanocomposites have become a hot research topic for material scientists. Compared with traditional composite materials, nanocomposites have the characteristics of good mechanical properties, high thermal stability, superior flame retardancy and barrier properties. CaCO ₃ is the most commonly used filling material for thermoplastic polymers, and nano-calcium carbonate is the best among calcium carbonates, and it is the cheapest nano-material. Filling the nano-CaCO ₃ particles into the polymer can obtain a composite material with excellent comprehensive properties. Spinning the modified nano-CaCO ₃ /POM composite material is expected to obtain fibers with better mechanical and thermal properties.

Contents of the invention

The purpose of the present invention is to address the existing above-mentioned defects of pure POM fibers, adopt the method of modifying POM first, and then optimize the conditions of melt spinning and stretching to obtain nano-CaCO ₃ /POM with better mechanical and thermal properties Composite fibers. In terms of fiber-reinforced cement, compared with pure fiber, the surface of modified fiber is attached with small nano-calcium carbonate particles, which becomes rough, forming a greater grip force between the fiber surface and cement, so that the strength of cement is effectively improved. improve. In addition, the current price per ton of calcium carbonate on the market is 2,000 yuan per ton, which is only equivalent to one fourteenth of the price. The cost of the modified nano-CaCO ₃ /POM composite fiber can be greatly reduced, which is conducive to the popularization and application of fiber products, and fiber production plants can also obtain better economic benefits. Thirdly, the affinity between calcium carbonate and cement is good, the density ratio is nearly doubled, which is almost the same as that of cement, and the density of the modified fiber is higher than that of pure POM fiber. During the mixing process of fiber and cement and actual paving, fibers with low density are easily thrown to the edge layer or float on the surface of cement concrete, which seriously affects the distribution and reinforcement of fibers in concrete. The modified fiber with higher density can suppress this phenomenon to a certain extent, so that the fiber and cement can be fully mixed evenly in the actual use process, which also overcomes many defects of pure POM fiber in strengthening cement. .

The modified POM fiber of the present invention refers to that 1-9 wt% of nano-calcium carbonate and stearic acid with a mass fraction of 0.5-1.5% of the nano-calcium carbonate are uniformly dispersed in the POM fiber.

As a preferred technical solution:

A kind of modified POM fiber as described above, the mass fraction of described nanometer calcium carbonate accounting for described modified POM fiber is 5%.

A kind of modified POM fiber as described above, the massfraction that described stearic acid accounts for described nano calcium carbonate is 1.5%.

A modified POM fiber as described above, the particle size of the nanometer calcium carbonate is 50 to 500nm.

A modified POM fiber as described above, the particle size of the nano-calcium carbonate is 78nm.

The present invention also provides a kind of preparation method of modified POM fiber, comprises the following steps:

(1) Modified nano-CaCO ₃

First, modify nano-CaCO ₃ with stearic acid, put a certain amount of nano-CaCO ₃ into the drier, dry at 110°C for 1 hour, and add surface treatment agent stearic acid evenly when cooling to 80°C, its mass fraction It is 1.5% of the amount of nano-CaCO ₃ , mixed for 20 minutes, stopped stirring, and took it out for use.

(2) Blending and sticking

Before the pellets are put in, heat for 1 hour. When the temperature reaches 140°C, put the modified nano-CaCO ₃ and POM particles in a high-speed mixer with a rotation speed of 3000 to 5000r/min, using blending heating and oil The method of heating outside the bath is to heat to 150°C, and then close the high-speed blender after blending for 3 to 4 minutes, so that the nano-CaCO ₃ adheres firmly to the melted and softened POM particles, and there is no serious adhesion between the POM particles

(3) Melt spinning

The as-spun fibers were obtained by melt spinning, and the spinning parameters were set as follows: the spinning temperature was 205° C., the screw speed was 100 r/min, and the godet roll speed was 15 r/min;

(4) Stretch

The final modified POM fiber is obtained by stretching in a hot air bath, and the temperature in the heating device in the hot air bath stretching machine is set to 90-120°C, and the stretching ratio is 1-8 times;

According to a method for preparing modified POM fibers as described above, the mass fraction of the stearic acid in the nano-calcium carbonate is 0.5-1.5%.

According to a method for preparing modified POM fibers as described above, the mass fraction of the nano-calcium carbonate in the modified POM fibers is 1-9 wt%.

According to the preparation method of a modified POM fiber as described above, the particle size of the nanometer calcium carbonate is 50 to 500nm.

The modified fiber obtained by the invention is a nano CaCO ₃ /POM composite fiber, and compared with the pure POM fiber, the toughness and thermal stability are both improved. Compared with the pure POM fiber, the surface of the modified POM fiber becomes rough and the density becomes larger. Beneficial effect

Compared with pure POM, the mechanical and thermal properties of the modified nano-CaCO ₃ /POM composite fiber are better improved. At the same time, the surface of the modified POM fiber becomes rough, and the interface force with cement is enhanced; the density becomes larger, and the mixing effect is better in the blending with cement; the price of nano-CaCO ₃ is much lower than that of POM, and the cost of fiber is obvious Reduced, the economic benefit is remarkable. Therefore, the modified POM composite fiber has outstanding advantages in strengthening cement in the field of construction.

Detailed ways

The present invention will be further described below in combination with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

The modified POM fiber of the present invention refers to that 1-9 wt% of nano-calcium carbonate and stearic acid with a mass fraction of 0.5-1.5% of the nano-calcium carbonate are uniformly dispersed in the POM fiber. After modification, the surface of the fiber is roughened, and other materials are reinforced by the fiber, and the bonding effect of the interface will be improved. The mass fraction of the nano-calcium carbonate accounting for the modified POM fiber is 5%.

Described stearic acid accounts for the massfraction of described nano-calcium carbonate and is 1.5%.

The particle size of the nanometer calcium carbonate is 50 to 500nm.

The particle size of the nano-calcium carbonate is 78nm.

Example 1

A preparation method of modified POM fibers, comprising the following steps:

(1) Modified nano-CaCO ₃

First, modify nano-CaCO ₃ with stearic acid, put a certain amount of nano-CaCO ₃ into the drier, dry at 110°C for 1 hour, and add surface treatment agent stearic acid evenly when cooling to 80°C, its mass fraction It is 1.5% of the amount of nano-CaCO ₃ , mixed for 20 minutes, stopped stirring, and took it out for use.

(2) Blending and sticking

Before the pellets are put in, heat them for 1 hour. When the temperature reaches 140°C, put the modified nano-CaCO ₃ and POM particles in a high-speed mixer with a rotation speed of 3000r/min. The heating method is to heat to 150°C, and then close the high-speed blender after blending for 3 minutes, so that the nano-CaCO ₃ firmly adheres to the melted and softened POM particles, and there is no serious adhesion between the POM particles

(3) Melt spinning

The as-spun fibers were obtained by melt spinning, and the spinning parameters were set as follows: the spinning temperature was 205° C., the screw speed was 100 r/min, and the godet roll speed was 15 r/min;

(4) Stretch

The final modified POM fiber is obtained by stretching in a hot air bath, and the temperature in the heating device in the hot air bath stretching machine is set to 90°C, and the stretching ratio is 1 times;

A kind of preparation method of modified POM fiber as described above, the mass fraction of described nano-calcium carbonate accounting for described modified POM fiber is 1wt%.

According to the preparation method of a modified POM fiber as described above, the particle size of the nanometer calcium carbonate is 50 to 500nm.

Example 2

First weigh 1000g POM and 10g modified nano-CaCO ₃ , the mass of nano-CaCO ₃ is 1% of POM. Before the pellets are put in, the 200-liter high-speed blender is heated for 1 hour, and when the temperature reaches 140° C., the modified nano _CaCO and POM particles are put into the high-speed mixer, and the number of revolutions is 5000r/min. Heat to 150°C by means of blending heating and external heating in oil bath, and then close the high-speed blender after blending for 3 minutes, so that nano-CaCO ₃ is firmly adhered to the melted and softened POM particles, and there is no occurrence between POM particles. Severe adhesions. Then the nano-CaCO ₃ /POM composite was spun in a micro-blended spinning machine, and the spinning parameters were set as follows: the spinning temperature was 205°C, the screw speed was 100r/min, and the godet roll speed was 15r/min, and the obtained primary fiber.

Example 3

First weigh 1000g POM and 30g modified nano-CaCO ₃ , the mass of nano-CaCO ₃ is 3% of POM. Before the pellets are put in, the 200-liter high-speed blender is heated for 1 hour, and when the temperature reaches 140° C., the modified nano _CaCO and POM particles are put into the high-speed mixer, and the number of revolutions is 5000r/min. Heat to 150°C by means of blending heating and external heating in oil bath, and then close the high-speed blender after blending for 3 minutes, so that nano-CaCO ₃ is firmly adhered to the melted and softened POM particles, and there is no occurrence between POM particles. Severe adhesions. Then the nano-CaCO ₃ /POM composite was spun in a micro-blended spinning machine, and the spinning parameters were set as follows: the spinning temperature was 205°C, the screw speed was 100r/min, and the godet roll speed was 15r/min, and the obtained primary fiber.

Example 4

First weigh 1000g POM and 50g modified nano-CaCO ₃ , the mass of nano-CaCO ₃ is 5% of POM. Before the pellets are put in, the 200-liter high-speed blender is heated for 1 hour, and when the temperature reaches 140° C., the modified nano _CaCO and POM particles are put into the high-speed mixer, and the number of revolutions is 5000r/min. Heat to 150°C by means of blending heating and external heating in oil bath, and then close the high-speed blender after blending for 3 minutes, so that nano-CaCO ₃ is firmly adhered to the melted and softened POM particles, and there is no occurrence between POM particles. Severe adhesions. Then the nano-CaCO ₃ /POM composite was spun in a micro-blended spinning machine, and the spinning parameters were set as follows: the spinning temperature was 205°C, the screw speed was 100r/min, and the godet roll speed was 15r/min, and the obtained primary fiber.

Example 5

First weigh 1000g POM and 70g modified nano-CaCO ₃ , the mass of nano-CaCO ₃ is 7% of POM. Before the pellets are put in, the 200-liter high-speed blender is heated for 1 hour, and when the temperature reaches 140° C., the modified nano _CaCO and POM particles are put into the high-speed mixer, and the number of revolutions is 5000r/min. Heat to 150°C by means of blending heating and external heating in oil bath, and then close the high-speed blender after blending for 3 minutes, so that nano-CaCO ₃ is firmly adhered to the melted and softened POM particles, and there is no occurrence between POM particles. Severe adhesions. Then the nano-CaCO ₃ /POM composite was spun in a micro-blended spinning machine, and the spinning parameters were set as follows: the spinning temperature was 205°C, the screw speed was 100r/min, and the godet roll speed was 15r/min, and the obtained primary fiber.

Example 6

First weigh 1000g POM and 90g modified nano-CaCO ₃ , the mass of nano-CaCO ₃ is 8% of POM. Before the pellets are put in, the 200-liter high-speed blender is heated for 1 hour, and when the temperature reaches 140° C., the modified nano _CaCO and POM particles are put into the high-speed mixer, and the number of revolutions is 5000r/min. Heat to 150°C by means of blending heating and external heating in oil bath, and then close the high-speed blender after blending for 3 minutes, so that nano-CaCO ₃ is firmly adhered to the melted and softened POM particles, and there is no occurrence between POM particles. Severe adhesions. Then the nano-CaCO ₃ /POM composite was spun in a micro-blended spinning machine, and the spinning parameters were set as follows: the spinning temperature was 205°C, the screw speed was 100r/min, and the godet roll speed was 15r/min, and the obtained primary fiber.

Example 7

The as-spun fiber obtained in Example 4 is placed in a hot air bath drawing device, the rotating speed of the godet roller is 1r/s, the rotating speed of the right godet roller is 3r/s, and the draw ratio is 3. The temperature is set at 120°C to obtain a stretched fiber product.

Claims (3)

1. a preparation method of modified POM fiber is characterized in that comprising the following steps: (1) Modified nano-CaCO ₃ First, modify nano-CaCO ₃ with stearic acid, put a certain amount of nano-CaCO ₃ into the drier, dry at 110°C for 1 hour, add surface treatment agent stearic acid evenly when cooling to 80°C, and mix for 20 minutes Stop stirring, take out and set aside; (2) Blending and sticking Before the pellets are put into the high-speed blender, heat the high-speed blender for 1 hour. When the temperature reaches 140°C, put the modified nano-CaCO ₃ and POM particles into the high-speed blender with a rotation speed of 3000 to 5000r/min. The method of blending heating and heating outside the oil bath is heated to 150°C, and the high-speed blender is turned off after blending for 3 to 4 minutes, so that the nano-CaCO ₃ is firmly adhered to the melted and softened POM particles, and there is no gap between the POM particles. Severe adhesions occur; (3) Melt spinning The as-spun fibers were obtained by melt spinning, and the spinning parameters were set as follows: the spinning temperature was 205°C, the screw speed was 100r/min, and the godet roll speed was 15r/min; (4) Stretch The final modified POM fiber is obtained by stretching in a hot air bath, and the temperature in the heating device in the hot air bath stretching machine is set to 90 to 120°C, and the stretching ratio is 1 to 8 times; The obtained modified POM fiber is uniformly dispersed with nano-calcium carbonate and stearic acid in the POM fiber; Described stearic acid accounts for the massfraction of described nano-calcium carbonate to be 0.5～1.5%; The mass fraction of the nano-calcium carbonate in the modified POM fiber is 1-9 wt%. the 2. the preparation method of a kind of modified POM fiber according to claim 1 is characterized in that, described nanometer calcium carbonate particle diameter is 50 to 500nm. the 3. the preparation method of a kind of modified POM fiber according to claim 1 and 2 is characterized in that, described nano calcium carbonate particle diameter is 78nm. the