CN1412366A - Preparation method of composite fibre formed from glass fibre and polypropylene fibre - Google Patents

Abstract

The invention discloses a manufacturing method of composite fiber composed of glass fiber and polypropylene fiber. The method adopts a high-temperature heat-setting process for the stretched polypropylene fiber, which greatly reduces the shrinkage of the polypropylene fiber. The modified polypropylene raw material is used to effectively combine the glass fiber and polypropylene fiber interface. In the composite fiber produced by the method, the added amount of glass fiber is large, the distribution is uniform, and the strength is high.

Description

A kind of manufacturing method of composite fiber composed of glass fiber and polypropylene fiber

1. Technical field

The invention relates to the field of glass fiber-reinforced resin composite materials, and further relates to a manufacturing method of composite fibers formed by combining glass fibers and thermoplastic resin fibers.

2. Background technology

Due to the composite materials made of glass fiber reinforced various resin matrices have the characteristics of light weight, high strength, electrical insulation, corrosion resistance, flame retardancy, long service life, etc., they have been widely valued in the world, especially glass Fiber-reinforced thermoplastic resins such as polypropylene, polyethylene, etc., have occupied the dominant position of resin-based composite materials for a considerable period of time because of their economy, good impact toughness, easy molding, easy repair, and easy regeneration. This kind of composite material is generally made of glass fiber chopped particles mixed with thermoplastic resin particles, and then extruded through a screw extruder. The disadvantages of this method are: the amount of glass fiber added is not high, the strength is low, and the distribution of glass fibers is uneven. The alignment direction of glass fibers, etc. cannot be controlled. US patent specification US-5454846 discloses a composite fiber manufacturing process. In this process, the glass fiber flows out of the mold and moves along the first channel at a certain speed, while the thermoplastic fiber flows out of the wire drawing machine and moves along the second channel at another speed. The two fibers are bundled by a bundler and become a composite fiber. Due to the shrinkage of the thermoplastic fiber after being stretched, the composite fiber has corrugations. When winding into a coil, the winding is difficult due to the bulkiness of the fiber, and there are many adverse effects such as uneven mixing. In order to solve this problem, U.S. patent specification US-5454846 has adopted the method that makes thermoplastic fiber move faster than glass fiber move speed, makes after thermoplastic fiber shrinks in composite fiber and the length of glass fiber is consistent. Theoretically, this process can make the two fibers mix evenly, effectively control the arrangement direction of the fibers, increase the amount of glass fiber added, and improve product performance. However, the above-mentioned method is not easy to control in actual production, so industrialized production has not been realized all the time. In addition, polypropylene is a non-polar polyolefin, which has poor affinity with glass fibers, and it is difficult for it to form an effective interfacial bond with glass fibers. In order to give full play to the reinforcing effect of glass fibers and obtain glass fiber reinforced polypropylene composites with excellent performance, it is necessary to try to improve the interface bonding strength between glass fibers and polypropylene. Since the surface of the glass fiber contains a large amount of silanol groups, the sizing agent is generally used to infiltrate the glass fiber directly, and the sizing agent mainly contains a polypropylene film-forming agent in addition to the coupling agent. This method is very effective for glass fiber-reinforced polar thermoplastic resins because the coupling agent can form chemical bonds with the resin, but for glass fiber-reinforced polypropylene, because polypropylene is a non-polar resin, the interface bond strength can only be slightly reduced. There is improvement.

3. Contents of the invention

In order to solve the problem of fluffy composite fibers caused by the shrinkage of polypropylene fibers and more effectively improve the interfacial bonding strength between glass fibers and polypropylene, and obtain composite fibers with excellent performance, the present invention conducts secondary thermal stretching on polypropylene fibers And high temperature heat setting treatment to reduce shrinkage. After stretching, the aggregated structure of the polypropylene fiber has changed greatly, usually in an unbalanced state, and its structure and properties can change with time. High-temperature heat-setting treatment can eliminate internal tension generated during stretching. Stress and new structural defects make the final structure of the fiber basically stable and its properties basically fixed, so that the shrinkage rate is greatly reduced. The heat treatment temperature is 100-120°C, preferably 110°C, and the treatment time is 5-10 seconds, preferably 6 seconds. In the present invention, by using the method of mixing raw materials of polypropylene and modified polypropylene, the polar groups in the polypropylene fibers are chemically bonded to the surface of the soaked glass fibers so as to improve the interfacial bonding strength between the glass fibers and the polypropylene, preferably Maleic anhydride modified polypropylene, the modified polypropylene content is 3-8%, preferably 5%.

4. Description of drawings and specific implementation

The technological process and beneficial effects of the present invention will be described in detail in conjunction with the accompanying drawings and specific implementation methods.

Accompanying drawing is the technological process schematic diagram of the present invention.

The invention adopts the method that the glass fiber forming system and the polypropylene fiber forming system are arranged side by side, respectively formed into filaments, stretched in a plane, combined in a plane, and bundled into bundles. The specific instructions are as follows: the clarified glass liquid flows out from the bushing (1) to form glass fibers (2), and the glass fibers are quickly cooled by spraying water to cool down, and then pass through a graphite roller oiler (3) to coat the sizing agent and infiltrate The agent contains silane coupling agent and photoinitiator. The leaking plate adopts a rectangular design to increase the diffusion area of fibers. There is a passage of glass liquid on the leakage plate, and the glass liquid is kept at a certain temperature by electric heating. The bushing material is platinum-rhodium alloy. Keep a certain distance between the nozzles so that the glass fibers are stretched in a plane. The polypropylene pellets containing 5% maleic anhydride-modified polypropylene are fed into the screw extruder from the hopper, and antioxidants, light stabilizers, and functional additives such as flame retardants can also be added as needed. It is melted by heating, and then flows out from the spinneret (4) to form polypropylene fibers (5), which are also rectangular. The polypropylene fiber is stretched in a plane, and after passing through a blowing cooling channel at a certain speed, it is drawn to three pairs of stretching rollers (7, 8), (9, 10), (11, 12) by the guide roller (6), In order to improve the strength of polypropylene fiber, reduce elongation, change molecular orientation, and control fiber diameter, it must be stretched by the above three pairs of stretching rollers. The first pair of stretching rollers (7, 8) are heated by resistors so that the temperature is controlled above the glass transition temperature of polypropylene and below the softening point. The rotating speed of the third pair of drawing rolls (11,12) is greater than the second pair and the same as the linear speed of the wire drawing machine (18), the rotating speed of the second pair of drawing rollers (9,10) is greater than the first pair, and the three pairs of drawing The stretching rollers are controlled by frequency conversion. In this way, the polypropylene fiber is stretched twice after passing through three pairs of stretching rollers. The stretched polypropylene fibers are drawn to a pair of heating rollers (13, 14). The heating rollers are heated by electricity, and the temperature is controlled at about 120°C. After 6 seconds of heat treatment, the shrinkage of the polypropylene fibers is greatly reduced. . Make it rapidly cooled to about 70 ℃ by cooling water roller (15) again. At this moment, the polypropylene fiber having composite requirements is co-extruded into a composite fiber between the press roller (16) place and the glass fiber. The composite fiber is finally integrated into a bundle by a bundler (17), and wound into a roll by a wire drawing machine (18), that is, the finished composite fiber. When using this composite fiber to make a composite material, it must be heated above the melting point of polypropylene. At this time, the polypropylene fiber acts as a matrix material and flows around the glass fiber to better coat and impregnate the glass fiber and produce better The interfacial bonding enables rapid molding under low pressure.

The composite fiber prepared by the above process is uniformly mixed, the glass fiber content in the composite fiber can reach 50-70%, the diameter of the glass fiber is between 13-17 μm, and the diameter of the polypropylene fiber is between 20-30 μm. The composite material made of the composite fiber has uniform fiber distribution, high strength, can effectively control the direction of fiber arrangement, and makes the product have excellent performance.

Claims (5)

1. the manufacture method of a composite fibre of forming by glass fibre and polypropylene fibre, glass fibre (2) flows out from a rectangle platinum-rhodium alloy bushing (1), apply sizing agent through water spray cooling back at baster (3), polypropylene fibre (5) flows out from a rectangle spinnerets (4), be drawn to draw roll (7 by lateral blowing cooling back by a guide roller (6), 8), (9,10), (11,12) on, at this polypropylene fibre is added hot-stretch, make it meet the requirements of diameter, locate alternate co-extrusion at pressure roller (16) then and become composite fibre with glass fibre, it is characterized in that: polypropylene fibre is drawn to warm-up mill (13 again after three pairs of draw roll places are through the secondary hot-stretch, 14) carry out high-temperature shaping on, use chill roll (15) cooling again, make the structure of polypropylene fibre and character basicly stable, contain polypropylene and modified polypropene in the raw material of polypropylene fibre.

2. method according to claim 1, the elevated temperature heat setting temperature of glass fibre is 110-125 ℃.

3. method according to claim 1 and 2, preferred 120 ℃ of the elevated temperature heat setting temperature of glass fibre.

4. method according to claim 1, the preferred maleic anhydride modified polypropylene of modified polypropene, its content is 3-8%.

5. method according to claim 4, maleic anhydride modified polyacrylic content preferred 5%.

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