CN1158172C - Preparation method of sisal fiber modified granules - Google Patents

Abstract

The invention relates to sisal fiber modified granules, a preparation method thereof and application thereof in composite materials, which is characterized in that: the sisal hemp short fiber modified granular material is prepared by mixing a sisal hemp fiber string with a modifier, cooling and then cutting into granules, wherein the length of the sisal hemp short fiber modified granular material obtained by cutting into granules is 2-20 mm; the preparation method comprises the following steps: preparing a sisal hemp fiber raw material string, enabling the string to pass through a molten modifier, enabling the modifier to permeate into gaps among independent fiber filaments of the string and wrap the string, and cutting the string into sisal hemp short fiber modified granules after cooling. The invention is suitable for producing corresponding composite materials by injection, extrusion or hot pressing and other forming methods, and has the advantages of simple process, environmental protection and the like.

Description

Preparation method of sisal fiber modified pellets

technical field

The invention relates to sisal fiber modified pellets, a preparation method thereof, and an application in composite materials, and belongs to the technical field of sisal fiber resin-based composite materials, a manufacturing method and application thereof.

Background technique

The preparation method of the sisal fiber/resin matrix composite material of prior art has following three kinds: the first, hot-press method prepares unidirectional sisal fiber/unsaturated polyester laminated composite material, or hot-press method prepares unidirectional sisal fiber Hemp fiber/epoxy laminate composite. This process has the disadvantages of complex equipment structure, complex preparation process, and is only suitable for the preparation of unidirectional sisal fiber and unsaturated polyester composite materials (narrow application range). Second, the melt blending or solution blending method is used to manufacture short sisal fiber/low-density polyethylene composites, but the melt blending method is easy to damage the sisal fiber, and there are shortcomings such as product strength, toughness and other performance declines; solution blending The method uses toxic solvents, which has the disadvantages of polluting the environment and high cost. Third, an invention patent application with the name "Preparation Method of Sisal Fiber/Resin Matrix Composite Material" and application number "97108948.5" disclosed in the Chinese Patent Gazette is characterized by the use of pretreated and chopped swords Hemp tow or woven non-woven fabric is used as raw material, mixed with a certain amount of thermoplastic resin PVC, thermosetting resin phenolic resin PF or epoxy resin Epo matrix under certain conditions, after drying, it is hot-pressed under certain temperature and pressure conditions. This patent application cannot be injection molded or extruded, and has the disadvantages of single production method, low efficiency, and long cycle.

Contents of the invention

The object of the present invention is to provide a kind of sisal fiber modified pellet and Its preparation method and application in composite materials, the sisal fiber modified pellets are suitable for injection or extrusion molding, and the preparation method has high efficiency, short cycle time and environmental protection.

The purpose of the present invention can be achieved by taking the following measures: sisal fiber modified pellets, which are characterized in that: by mixing and granulating sisal fiber strings and modifiers, the modifiers penetrate into the strings The gaps between the independent fiber filaments and the strings are wrapped, and the length of the sisal fiber modified pellets obtained by granulation is 2-20 mm.

A kind of preparation method of sisal fiber modified pellet as mentioned above, it is characterized in that: first prepare sisal fiber raw material string, let described string pass through the modifier of melting, make modifier infiltrate Describe the space between the independent fiber filaments of the string and wrap the string, and make sisal fiber modified pellets after cooling, the specific steps are:

①First prepare the sisal fiber single-strand string with a diameter of 1-8mm: use a special spinning machine to spin the sisal fiber raw material into a single-strand string with a diameter of 1-8mm or buy a ready-made sword with a diameter of 1-8mm Hemp fiber single-strand thin rope;

② passing the aforementioned sisal fiber single-strand thin rope through the molten low-viscosity modifier, so that the modifier penetrates into the spaces between the independent fiber filaments of the thin rope, and the thin rope is covered by the low-viscosity modifier. Wrapped up, cooled to form a solidified string, and then cut into sisal fiber modified pellets with a length of 2 to 20 mm;

③Put the sisal fiber modified pellet packaging product obtained in step ② into storage or sell.

As mentioned above, the preparation method of sisal fiber modified pellets is characterized in that the whole preparation process is completed by a set of special equipment, and the special equipment consists of a spinning device, a fixing and winding device, a traction and a conveyor, an improved It is composed of a modifier container, a cooling and controller, and a granulator, and a heating and thermostat are installed on the modifier container.

The sisal fiber raw material is spun into a single-strand thin rope with a diameter of 1-8mm by the rope spinning device 1, and the single-strand thin rope is wound into a coil by the fixed and winder 2, and the coil is pulled by the traction and conveyor 6 Down through the modifier holder 3 and soaked in the molten modifier 7, the modifier 7 infiltrates the space between the independent fiber filaments of the string and wraps the string, and is absorbed by the modifier 7. The wrapped single-strand thin rope is cooled by the controller 5 to become a hardened thin rope. The hardened thin rope enters the granulator 8 under the traction of the traction and the conveyor 6 and is chopped into sisal hemp with a length of 2-20 mm. Fiber modified pellets 9, sisal fiber modified pellets 9 are arranged in bundles, and the gaps between the independent fiber filaments 10 of each pellet 9 are filled by cured modifier 7, so that the sisal fiber 10 and modified Agent 7 constitutes a modified pellet as a whole.

As mentioned above, the sisal fiber modified pellet is characterized in that the modified agent used has the following characteristics:

① consisting of one or more components, the main component in the modifier can improve the compatibility between the sisal fiber raw material and the selected thermoplastic resin-based raw material;

② It is thermoplastic, its melting temperature is lower than the melting point of the thermoplastic resin-based raw material used, and its decomposition temperature is higher than the processing and molding temperature of the corresponding composite material;

③The viscosity is low enough after melting, and can penetrate into the space between the individual filaments of the string and wrap the string through the action of the capillary;

4. After cooling, each independent sisal fiber filament in the string can be bonded and fixed together, and the solidified string obtained can be cut into shaped sisal fiber modified pellets through a pelletizer.

As mentioned above, the sisal fiber modified pellet is characterized in that the weight ratio of modifier to sisal fiber is 3-50:100.

As previously mentioned, the purposes of sisal fiber modified pellets in composite materials is characterized in that: the abovementioned sisal fiber modified pellets are mixed with a certain amount of thermoplastic resin raw materials, and stirred by mechanical stirring at normal temperature to Fully mixed to make a sisal fiber/thermoplastic resin base composite premix, and then further extruding and granulating the composite premix to obtain a sisal fiber/thermoplastic resin base suitable for direct injection, extrusion or thermocompression molding Composite pellets.

As mentioned above, the use of sisal fiber modified pellets in composite materials is characterized in that: under certain conditions, the composite premix is made into composite material products by molding methods such as injection, extrusion or hot pressing .

As previously mentioned, the purposes of sisal fiber modified pellets in composite materials is characterized in that: in the sisal fiber/thermoplastic resin matrix composite premix, the weight ratio of modified pellets and thermoplastic resin raw materials is at 2: Adjust between 98 and 90:10.

As mentioned above, the use of sisal fiber modified pellets in composite materials is characterized in that: in the sisal fiber/thermoplastic resin-based composite premix, the thermoplastic resin raw materials used include polypropylene (PP), polyethylene (PE), polystyrene (PS), ABS, polyvinyl chloride (PVC), polyester and polyamide (PA).

As mentioned above, the use of sisal fiber modified pellets in composite materials is characterized in that: in the sisal fiber/thermoplastic resin-based composite premix, the thermoplastic resin raw material used is a biodegradable polymer base raw material.

Compared with the prior art using thermosetting resin-based raw materials, the present invention has the following outstanding advantages:

1. the present invention owing to be to prepare sisal fiber single-strand thin rope earlier: sisal fiber raw material is spun into single-strand thin rope or directly adopts ready-made sisal fiber single-strand thin rope; Single-strand thin rope is made of special modifier treatment, the modifier penetrates into the space between the individual filaments of the string and wraps the string, and cuts into pellets after cooling; therefore, it can be produced by efficient injection and extrusion molding, with high production efficiency, low cost;

2. The special modifier used can improve the compatibility between the sisal fiber raw material and the selected thermoplastic resin-based raw material, and the melting temperature is lower than the melting point of the thermoplastic resin-based raw material, and the decomposition temperature is higher than that of the corresponding composite material. Molding temperature, the performance of the finally prepared sisal fiber/thermoplastic resin-based composite material is controllable, and the performance-price ratio is high;

3. The processing and molding process is safe and harmless, and will not cause environmental pollution;

4. Can be recycled;

5. Biodegradable treatment is possible.

Description of drawings

Fig. 1 is the structural representation and process flow diagram of special equipment used in the present invention.

Fig. 2 is a structural schematic diagram of sisal fiber modified pellets.

Fig. 3 is a process flow diagram of an application example of the present invention.

Fig. 4 is a process flow diagram of an application example of the present invention.

Detailed ways

What application example 1 of the present invention has described is the method for preparing sisal fiber/thermoplastic resin matrix composite material, used raw material comprises: sisal fiber string, modifier → low molecular weight maleic anhydride grafted propylene copolymer, thermoplastic resin Base material → general purpose polypropylene resin. The preparation process is firstly to make modified pellets, and then to make sisal fiber/thermoplastic resin matrix composite material. The specific methods and steps are as follows:

①Prepare the sisal fiber single-strand thin rope with a diameter of 3mm: you can use special equipment to spin the sisal fiber raw material into a single-strand thin rope with a diameter of 3mm, or directly purchase a single-strand thin rope with a diameter of 3mm;

② Melting the modifier into a low-viscosity melt;

3. the aforementioned single-strand string passes through the modifier melt melted on the special equipment, the cooler 5, and the pelletizer 8, and the modifier melt penetrates into the space between each independent fiber filament of the string, so that the The thin rope is wrapped by the low-viscosity modifier, and after cooling, it becomes a solidified thin rope, and then cut into sisal fiber modified pellets with a length of 4 to 6 mm. In the modified pellets, the modifier and the sisal fiber The weight ratio is 15:100;

④Pack the modified sisal fiber pellets obtained in step ③ into products; or mix them with quantitative general-purpose polypropylene resin, and stir them with mechanical stirring at normal temperature until they are fully mixed to obtain a product suitable for direct injection, extrusion, etc. The premix of sisal fiber/thermoplastic resin-based composite material is produced by extruding or thermocompression molding, and the weight ratio of modified pellets and general-purpose polypropylene resin is 30:70;

5. Further extruding and granulating the composite premix obtained in 4. to obtain sisal fiber/thermoplastic resin-based composite material pellets suitable for direct injection, extrusion or thermocompression molding; or under certain conditions, use injection , Extrusion or hot pressing and other molding methods to make composite products.

The special equipment used in this embodiment is composed of spinning rope 1, fixing and winder 2, traction and conveyer 6, modifier holder 3, cooling and controller 5, pelletizer 8, modifier holder The bottom of device 3 is equipped with heating and thermostat 4.

The raw materials used in the application example 2 of the present invention include: sisal fiber, modifier → low molecular weight ethylene-vinyl acetate copolymer, thermoplastic resin-based raw material → high-density polyethylene resin. The weight ratio of the modifying agent to the sisal fiber is 20:100; the weight ratio of the prepared modified pellets to the thermoplastic resin is 20:80. The preparation method and steps are the same as those in Application Example 1.

In the application example 3 of the present invention, the raw materials used include: sisal fiber, modifier → low molecular weight polyhydactam; thermoplastic resin-based raw material → polybutylene terephthalate resin. The weight ratio of the modifying agent to the sisal fiber is 20:100; the weight ratio of the prepared modified pellets to the thermoplastic resin is 20:80. The preparation method and steps are the same as those in Application Example 1.

The raw materials used in Application Example 4 of the present invention include: sisal fiber, modifier → low molecular weight styrene-butylene-styrene copolymer; thermoplastic resin-based raw material → high-impact polystyrene resin. The weight ratio of the modifying agent to the sisal fiber is 20:100; the weight ratio of the prepared modified pellets to the thermoplastic resin is 20:80. The preparation method and steps are the same as those in Application Example 1.

Application example 5 of the present invention is: the sisal fiber raw material is spun into the single-strand thin rope that diameter is 2mm with special-purpose equipment, and the modified granular material that step 2 is made in application example 1 is cut into the sisal hemp that length is 5mm Fiber modified pellets. The rest are the same as application example 1 or example 2 or example 3.

Application example 6 of the present invention is: the sisal fiber raw material is spun into the single-strand thin rope of 4mm in diameter with special equipment, and the modified granular material that step 2 is made in application example 1 is cut into the sisal hemp of 7mm in length Fiber modified pellets. The rest are the same as application example 1 or example 2 or example 3.

Application example 7 of the present invention is: the sisal fiber raw material is spun into the single-strand thin rope of 5mm in diameter with special equipment, and the modified granular material that step 2 is made in application example 1 is cut into the sisal hemp of 8mm in length Fiber modified pellets. The rest are the same as application example 1 or example 2 or example 3.

Application example 8 of the present invention is: the sisal fiber raw material is spun into the single-strand thin rope that diameter is 6mm with special equipment, and the modified pellet that step 2 in application example 1 is made is cut into the sisal hemp that length is 7mm Fiber modified pellets. The rest are the same as application example 1 or example 2 or example 3.

Application example 9 of the present invention is: among the application example 1, the modified pellet that the ② step is made is cut into the sisal fiber modified pellet that length is 11mm. All the other are the same as application example 5 or example 6 or example 7 or example 8.

Application example 10 of the present invention is: in the application example 1, the modified pellet that the ② step is made is cut into the sisal fiber modified pellet that length is 12mm. The rest are the same as application example 1 or example 6 or example 2 or example 3.

Application example 11 of the present invention is: among the application example 1, the modified granular material that the ② step is made is cut into the sisal fiber modified granular material that length is 13mm. All the other are the same as application example 5 or example 6 or example 7 or example 8.

Application example 12 of the present invention is: in application example 1, the modified granular material that step 2 is made is cut into the sisal fiber modified granular material that length is 15mm. All the other are the same as application example 5 or example 6 or example 7 or example 8.

Application example 13 of the present invention is: in the application example 1, the modified pellet that the ② step is made is cut into the sisal fiber modified pellet that length is 16mm. All the other are the same as application example 5 or example 6 or example 7 or example 8.

Application example 14 of the present invention is: among the application example 1, the modified granular material that the ② step is made is cut into the sisal fiber modified granular material that length is 18mm. All the other are the same as application example 5 or example 6 or example 7 or example 8.

Application example 15 of the present invention is: among the application example 1, the modified granular material that the ② step is made is cut into the sisal fiber modified granular material that length is 20mm. All the other are the same as application example 5 or example 6 or example 7 or example 8.

Claims (2)

1. the preparation method of a modified particles of sisal hemp fibre, it is characterized in that: at first be ready to sisal fiber raw material cord, allow the modifier of described cord by fusion, make modifier infiltrate the space between the individual fibers silk of described cord and cord wrapped up, make modified particles of sisal hemp fibre after the cooling, concrete steps are:

1. at first being ready to diameter is the sisal fiber sub-thread cord of 1～8mm: spin the rope device to be spun into diameter be the sub-thread cord of 1～8mm or buy the sisal fiber sub-thread cord that ready-made diameter is 1～8mm the sisal fiber raw material with special-purpose;

2. with the low viscosity modifier of aforementioned sub-thread cord by fusion, make modifier infiltrate space between each individual fibers silk of described cord, described cord is wrapped up by described low viscosity modifier, and the cooling back becomes to solidify cord, is cut into the modified particles of sisal hemp fibre that length is 2～20mm again;

3. with the 2. the modified particles of sisal hemp fibre that obtains of step be packaged into product warehousing or sale.

2. the preparation method of modified particles of sisal hemp fibre according to claim 1; be characterized in: whole process of preparation is finished by a cover isolated plant; described isolated plant is formed by spinning rope device (1), fixing and coiler (2), traction and conveyer (6), modifier holder (3), cooling and controller (5), pelleter (8), and heating and thermostat (4) composition is set on the modifier holder (3).

Images