CN107189059A - A kind of polyamide solid phase thickening control ball and application - Google Patents

Abstract

The invention belongs to the technical field of polymer preparation, and discloses a polyamide solid-phase thickening control ball and its application. The control ball is composed of one end connected together, and the other end is spherically divergent in three-dimensional space. The blade is composed of a surface layer with a mesh structure, an inner filter layer and an inner space in sequence from the outside to the inside. The above-mentioned internal space is filled with inorganic particles, and the inner filter layer can realize the passage of gas and prevent the leakage of inorganic particles. The control ball blade of the present invention can provide a separation layer for solid polyamide or copolyamide slices, and promote the turning energy of the slices in the dynamic state, and control the movement of the polyamide or copolyamide slices in the ball along the blades, thereby strengthening the turning of the slices; At the same time, it can be adsorbed by the inorganic particles in the blade, which is beneficial to the overflow of water vapor in the polyamide or copolyamide slices, to achieve the effect of intensified stirring, and then slowly release the acid gas, thereby promoting the process of solid phase thickening.

Description

A polyamide solid-phase thickening control ball and its application

technical field

The invention belongs to the technical field of polymer preparation, and in particular relates to a polyamide solid-phase thickening control ball and its application.

Background technique

Polyamide (PA, commonly known as nylon) has a history of more than 70 years since it was developed and industrialized by DuPont in the United States in the 1930s. There are hydrogen bonds between polyamide molecules, which endow polyamide with good affinity and good adhesion to many materials. At the same time, polyamide also has excellent mechanical properties, high strength, wear resistance, self-lubrication, oil resistance, and Chemicals and other excellent properties, so polyamide can be used as fiber, also can be used as engineering plastics, has a wide range of application prospects in industry. In order to obtain better mechanical properties, it is often necessary to increase the molecular weight of the polymer in a certain way, so as to reduce the proportion of polymer molecular chain tails as much as possible, so as to obtain high molecular weight (high viscosity) polyamide raw materials.

In the polycondensation process of polyamide, prolonging the holding time in the late stage of polymerization can directly increase the molecular weight of the polymer, but it makes it difficult to discharge high-viscosity polyamide in the molten state. Therefore, it is necessary to realize the preparation of high-viscosity polyamide chips by other means. Solid state polycondensation is a common and effective method.

Solid-state polycondensation (SSP) is a polycondensation reaction carried out in a solid state. As early as the 1930s, Flory discovered that the polyamide obtained by melt polycondensation could continue to undergo polycondensation reaction at a certain temperature in the solid state. With the deepening of research, people have been able to obtain high-quality, high-performance, high-molecular-weight polymers through solid-state polycondensation, especially for the polycondensation process of monomers that have a high melting point or are easily decomposed above the melting point, and For high temperature resistant polymers, solid state polycondensation is an important polymerization method. Solid-state polycondensation is a process in which monomers or prepolymers with lower molecular weights are heated above the glass transition temperature and below the melting point for polycondensation. At this time, the macromolecular chain is still in a fixed state, and the terminal functional groups have obtained enough activity to approach and react with each other through diffusion. The polycondensation reaction proceeds forward, so that the molecular weight of the product is continuously increased, and finally a high-viscosity copolymer is obtained. The characteristics of solid-state polycondensation are as follows: (1) The reaction temperature is significantly lowered, and by-products and degradation reactions are significantly reduced. (2) The relative molecular weight of the polymer can be significantly increased, thereby improving its mechanical properties. (3) The solid-state polycondensation temperature is low, and the stirring of the high-viscosity melt is avoided, so that the energy consumption of the entire polycondensation process is reduced. (4) Solid-state polycondensation does not require the use of solvents, and is an environmentally friendly polymerization reaction. (5) The polymerization process is simple and flexible; the polymerization method can be operated continuously or intermittently. (6) The reaction is stable, and high pressure is not required, and the requirements for equipment and materials are low.

In the process of solid-phase thickening, the effective detachment of small molecules can make the polycondensation reaction proceed in the direction of polymerization, so it is more conducive to promoting the improvement of solid-phase thickening effect. Therefore, in actual industrial production, polyamide slices to be tackified are often in a certain state of motion. In addition, according to the polyamide polycondensation mechanism, the acidic environment is conducive to the polycondensation. Therefore, appropriately improving the pH value of the polycondensation environment is also conducive to the improvement of the solid-phase thickening effect.

The solid-phase thickening process in industry is usually carried out in a rotating vacuum drum (vacuum dryer). sticky process. However, only through the rotation of the vacuum drum, the removal efficiency and viscosity-increasing effect of small molecules need to be further improved.

Contents of the invention

In view of the above shortcomings and deficiencies in the prior art, the primary purpose of the present invention is to provide a polyamide solid-phase viscosity-increasing control ball.

Another object of the present invention is to provide the application of the above-mentioned solid-phase thickening control ball in polyamide or copolyamide solid-phase thickening.

The object of the invention is achieved through the following technical solutions:

A polyamide solid-phase viscosity-increasing control ball, which is composed of blades connected at one end and spherically diverging at the other end in three-dimensional space. The inner space is filled with inorganic particles, and the inner filter layer can realize the passage of gas while preventing the leakage of inorganic particles.

Preferably, the number of the blades is 3-12.

Preferably, the blade is a willow-like structure, the length a of the blade is not less than the width b, wherein the values of a and b range from 0.5 to 20 mm, and the twist angle of the blade ranges from 10 to 65°.

Preferably, the surface layer with a mesh structure is a stainless steel layer with a mesh structure, the mesh density is 50-800 mesh, the mesh is circular, elliptical or rectangular, and the diameter or length and width of the mesh are 0.2 ~2.0mm. The stainless steel includes but not limited to 301 stainless steel, 302 stainless steel, 304 stainless steel, 309 stainless steel, 316 stainless steel, 321 stainless steel, 440 stainless steel.

Preferably, the inner filter layer is a high temperature resistant polymer filter layer, including but not limited to a single layer or two or more layers with a grammage of 40g/m ² to 300g/m ² Polyphenylene sulfide non-woven or woven fabric, polyacrylonitrile non-woven or woven fabric.

Preferably, the inorganic particles include but not limited to citric anhydride, disodium hydrogen phosphate, and sodium dihydrogen phosphate. After absorbing water, the inorganic particles realize the slow-release overflow of acidic components as the water evaporates.

The application of the above-mentioned solid-phase thickening control balls in polyamide or copolyamide solid-phase thickening, the application process is: directly mix the control balls with the polyamide or copolyamide slices to be thickened, and then enter the intermittent solid phase The solid-state polycondensation reaction is carried out in the thickening device to obtain high-viscosity polyamide or copolyamide.

The control ball of the present invention has the following advantages and beneficial effects:

The control ball blade of the present invention can provide a separation layer for solid polyamide or copolyamide slices, and promote the turning of the slices in dynamic state, and control the movement of the polyamide or copolyamide slices in the ball along the blades, thereby strengthening the turning of the slices; At the same time, it can be adsorbed by the inorganic particles in the blade, which is beneficial to the overflow of water vapor in the polyamide or copolyamide slices, to achieve the effect of intensified stirring, and then slowly release the acid gas, thereby promoting the process of solid phase thickening.

Description of drawings

Fig. 1 is the three views (a: front view; b left view; c: top view) of polyamide solid-phase thickening control ball in embodiment 5;

Fig. 2 is a schematic diagram of the structure of the polyamide solid-phase thickening control leaf-like structure leaves in Example 5 (a: contour diagram; b: internal structure diagram).

detailed description

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

A polyamide solid-phase viscosity-increasing control ball in this embodiment is composed of three leaves with a willow-leaf structure that are connected together through a central sphere at one end and diverge spherically at the other end in three-dimensional space. The length a of the leaves is 20 mm, and the width b is 10mm, and the blade twist angle is 30°. The blade and the central sphere are composed of a surface layer with a mesh structure, an inner filter layer and an inner space. The surface layer uses No. 301 stainless steel layer, the mesh density is 800 mesh, and the diameter of the circular mesh is 0.2mm. The inner layer of the blade uses polyphenylene sulfide non-woven fabric as a high-temperature-resistant non-woven fabric filter layer, and the grammage of the non-woven material is 300g/ ^m2 ; the inner space uses sodium dihydrogen phosphate as inorganic particles to absorb moisture Finally, with the evaporation of water, the slow-release overflow of acidic ingredients is realized. The inner filter layer allows gas to pass through while preventing the leakage of inorganic particles.

The control ball of this example is used to prepare high-viscosity copolyamide 6/66 by the batch method, and the control ball is directly mixed with the copolyamide 6/66 chips that need to be thickened, and then enters a batch-type solid-phase thickening device for solid-state polycondensation reaction to obtain high-viscosity polyamide or copolyamide. The results show that the viscosity of copolyamide 6/66 increases from 2.8 to 4.0 in 16-24 hours in a vacuum rotary drying drum at 165°C. It takes 32 to 40 hours to achieve the same viscosity-increasing effect under the same drying equipment and drying temperature without adding control balls.

Example 2

A polyamide solid-phase viscosity-increasing control ball of this embodiment is composed of 12 willow-leaf-shaped blades with one end connected together by a central sphere and the other end spherically diverging in three-dimensional space. The length a of the blade is 0.5 mm, and the width b is 0.5mm, and the blade twist angle is 10°. The blade and the central sphere are composed of a surface layer with a mesh structure, an inner filter layer and an inner space. The surface layer uses No. 304 stainless steel layer, the mesh density is 50 mesh, the major axis diameter of the oval mesh is 1.0mm, and the minor axis diameter is 0.4mm. The inner layer of the blade uses two layers of polyacrylonitrile non-woven fabric as a high-temperature resistant non-woven layer filter screen, and the grammage of the non-woven material is 40g/m ² ; the internal space uses disodium hydrogen phosphate and sodium dihydrogen phosphate (The mass ratio is 1:1) As inorganic particles, after absorbing water, the slow-release overflow of acidic components can be realized with the evaporation of water. The inner filter layer allows gas to pass through while preventing the leakage of inorganic particles.

The control ball of this embodiment is used in the batch method to prepare high-viscosity polyamide 66. After the control ball is directly mixed with polyamide 66 slices that need to be thickened, it is put into a batch-type solid-phase thickening device for solid-phase polycondensation reaction to obtain high-viscosity polyamide 66. Adhesive polyamide or copolyamide. The results show that the time for the viscosity of polyamide 66 to increase from 2.8 to 4.0 in a vacuum rotary drying drum at 245°C is 18 to 24 hours. It takes 32 to 40 hours to achieve the same viscosity-increasing effect under the same drying equipment and drying temperature without adding control balls.

Example 3

A polyamide solid-phase viscosity-increasing control ball in this embodiment is composed of 12 willow leaf-shaped blades with one end connected together by a central sphere and the other end spherically diverging in three-dimensional space. The length a of the blade is 20 mm, and the width b is 15mm, and the blade twist angle is 45°. The blade and the central sphere are composed of a surface layer with a mesh structure, an inner filter layer and an inner space. The surface layer uses No. 302 stainless steel layer, the mesh density is 600 mesh, and the length and width of the rectangular mesh are divided into 2.0mm and 0.5mm. The inner layer of the blade uses polyphenylene sulfide warp and weft woven cloth as the high-temperature resistant filter screen layer, and the grammage of the woven cloth material is 250g/ ^m2 ; the inner space uses sodium dihydrogen phosphate as inorganic particles, and after absorbing water Slow-release overflow of acidic ingredients is achieved by evaporation. The inner filter layer allows gas to pass through while preventing the leakage of inorganic particles.

The control ball of this example is used to prepare high-viscosity copolyamide 6/66/10 by batch method, and the control ball is directly mixed with the slices of copolyamide 6/66/10 that need to be thickened, and then enters the batch solid phase thickening device Perform solid-state polycondensation reaction to obtain high-viscosity polyamide or copolyamide. The results show that the viscosity of copolyamide 6/66/10 increases from 2.8 to 4.0 in 16 to 24 hours in a vacuum rotary drying drum at 230°C. It takes 32 to 40 hours to achieve the same viscosity-increasing effect under the same drying equipment and drying temperature without adding control balls.

Example 4

A polyamide solid-phase viscosity-increasing control ball in this embodiment is composed of 8 willow-leaf-shaped blades with one end connected together by a central sphere and the other end spherically diverging in three-dimensional space. The length a of the blades is 16 mm, and the width b is 10.8mm, and the blade twist angle is 60°. The blade and the central sphere are composed of a surface layer with a mesh structure, an inner filter layer and an inner space. The surface layer uses No. 309 stainless steel layer, the mesh density is 400 mesh, and the diameter of the circular mesh is 0.8mm. The inner layer of the blade uses two layers of polyphenylene sulfide non-woven fabric as a high-temperature resistant non-woven layer filter screen, and the grammage of the single-layer non-woven material is 100g/m ² ; the inner space uses citric anhydride as inorganic particles, After absorbing water, the slow-release overflow of acidic ingredients is realized as the water evaporates. The inner filter layer allows gas to pass through while preventing the leakage of inorganic particles.

The control ball in this example is used to prepare high-viscosity copolyamide 6/12 by batch method, and the control ball is directly mixed with the copolyamide 6/12 chips that need to be thickened, and then enters a batch-type solid-phase thickening device for solid-state polycondensation reaction to obtain high-viscosity polyamide or copolyamide. The results show that the viscosity of copolyamide 6/12 increases from 2.8 to 4.0 in a vacuum rotary drying drum at 140°C for 20 to 28 hours. It takes 32 to 40 hours to achieve the same viscosity-increasing effect under the same drying equipment and drying temperature without adding control balls.

Example 5

A kind of polyamide solid-phase thickening control ball of this embodiment, its three views are as shown in Figure 1 (a: front view; b left side view; c: top view), connected together by a central sphere at one end, the other end is in It is composed of 10 willow-like structural leaves that are spherically divergent in three-dimensional space. The structure schematic diagram of the willow-like structure blade is shown in Figure 2 (a: outline; b: internal structure diagram), the blade length a is 20mm, the width b is 8mm, and the blade twist angle 2θ is 65°. The blade and the central sphere are composed of a surface layer with a mesh structure, an inner filter layer and an inner space. The surface layer uses No. 440 stainless steel layer, the mesh density is 600 mesh, and the diameter of the circular mesh is 0.4mm. The inner layer of the blade uses polyacrylonitrile warp and weft woven cloth as the high-temperature resistant filter screen layer, and the grammage of the woven cloth material is 240g/m ² ; the inner space uses sodium dihydrogen phosphate as inorganic particles, and after absorbing water, it is Evaporates to achieve a slow-release overflow of the acidic ingredient. The inner filter layer allows gas to pass through while preventing the leakage of inorganic particles.

The control ball of this embodiment is used in the batch method to prepare high-viscosity polyamide 6. After the control ball is directly mixed with polyamide 6 slices that need to be thickened, it is put into a batch-type solid-phase thickening device for solid-phase polycondensation reaction to obtain high-viscosity polyamide 6. Adhesive polyamide or copolyamide. The results show that the time for the viscosity of polyamide 6 to increase from 2.8 to 4.0 in a vacuum rotary drying drum at 210° C. is 16 to 24 hours. It takes 32 to 40 hours to achieve the same viscosity-increasing effect under the same drying equipment and drying temperature without adding control balls.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (7)

1. A polyamide solid-phase viscosity-increasing control ball is characterized in that: the control ball is connected together by one end, and the other end is made of spherically divergent blades in three-dimensional space, and the blades are sequentially composed of The surface layer of the mesh structure, the inner filter layer and the inner space are composed, the inner space is filled with inorganic particles, and the inner filter layer can realize the passage of gas while preventing the leakage of inorganic particles. 2. A polyamide solid-phase thickening control ball according to claim 1, characterized in that: the number of the blades is 3-12. 3. A polyamide solid-phase thickening control ball according to claim 1, characterized in that: the blade is a willow-like structure, and the length a of the blade is not less than the width b, wherein the value range of a and b is 0.5~20mm, blade twist angle range is 10~65°. 4. A polyamide solid-phase thickening control ball according to claim 1, characterized in that: the surface layer with a mesh structure is a stainless steel layer with a mesh structure, and the mesh density is 50 to 800 meshes, The meshes are circular, elliptical or rectangular, and the diameter or length and width of the meshes range from 0.2 to 2.0mm. 5. A polyamide solid-phase thickening control ball according to claim 1, characterized in that: the inner filter layer is a single layer or two or more layers with a grammage of 40g/m ² -300g/m 2 . ^m2 polyphenylene sulfide non-woven or woven fabric, polyacrylonitrile non-woven or woven fabric. 6. A polyamide solid-phase thickening control ball according to claim 1, characterized in that: the inorganic particles are citric anhydride, disodium hydrogen phosphate or sodium dihydrogen phosphate. 7. The application of a polyamide solid-phase thickening control ball according to any one of claims 1 to 6 in polyamide or copolyamide solid-phase thickening, characterized in that the application process is: the control ball is directly After being mixed with the polyamide or copolyamide chips that need to be thickened, it enters the intermittent solid-phase thickening device for solid-state polycondensation reaction to obtain high-viscosity polyamide or copolyamide.