JPS6040455B2 - Method for manufacturing reinforced thermoplastic resin - Google Patents

Description

[Detailed Description of the Invention] This invention is a reinforced thermoplastic resin pellet (hereinafter simply referred to as a reinforced pellet) that improves the mechanical strength of a thermoplastic resin.
The present invention relates to a continuous manufacturing method.

The manufacturing method for this type of reinforced pellet is to mix cylindrical thermoplastic resin pellets or powdered plastic resin with three ribs of short fibers such as glass fibers of different lengths, and then mold the pellets using an extruder or the like. In other words, it is known that the material is heated and melted and then shaped.

However, in this manufacturing method, the mixing process and the molding process are different, so it is not possible to continuously manufacture reinforced pellets, and it has been a technical issue to simplify the manufacturing method. Furthermore, in this method, when the mixture of fibers and thermoplastic resin is supplied to the extruder via the hopper, it must pass through a narrow passage in the supply port, so long fibers cannot be used. In addition, these short fibers exhibit the phenomenon of fiber breakage during mixing and due to the screw inside the extruder main body,
According to the inventors' analysis and observation, when the thus obtained reinforced pellets are used as a molding material and molded using an injection molding machine, most of the fiber lengths dispersed inside the molded product are approximately 0. It was confirmed that there was an almost normal distribution with a median value on the .3 side. On the other hand, it is known that the longer these fibers are, the more the mechanical strength of the thermoplastic resin is improved. Therefore, it is not an effective method in terms of performance regarding the mechanical strength of the reinforced pellet. Furthermore, a technique is known in which single fibers such as glass fibers are assembled into glass fibers using a binding agent and a coupling agent.

Here, the binding agent is a substance that has the effect of bundling fibers with binding properties as is well known, and the coupling agent is a substance that increases the interfacial bond between the fiber and the thermoplastic resin.
This has the effect of improving the strength of the reinforced pellet. However, it is known that the binding agent reduces the effect of the coupling agent, and the mainstream of the industry is focusing on the development of a binding agent that reduces the effect of the coupling agent. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing reinforced pellets continuously without reducing the effect of the coupling agent and with less breakage of glass fibers.

The purpose of this invention is to use graphite, which has a lubricating effect, instead of a focusing agent, and to wash tens to thousands of rovings, soak them in a coupling agent solution in which graphite is suspended, and then add gold. It is guided into a mold and placed inside the thermoplastic resin supplied from an extruder connected to the mold at the same time, drawn out linearly from the mold by a drawing machine, and then cut into the desired length by a cutting machine. achieved by.

This invention will be described in detail below with reference to FIGS. 1 to 3.

First of all, in the first illustration, 1 is a roving, and a bundle of linear fibers 2 taken out from this is usually made of several tens to rovings in advance.
It is a bundle of several hundred single fibers, and the predetermined number of filaments can be gathered together, or the predetermined number of fibers can be individually placed at intervals in the cleaning tank 8.
, the concentrating agent previously deposited on the roving is washed, and the cleaning solution deposited on the surface is dried in a drying oven in step 4, followed by surface treatment containing a coupling agent solution 5 in which graphite is suspended. The surface is treated in tank 6, and the solvent deposited here is removed in tank 7.
After being volatilized in a dryer, it is passed through a mold 8. The fibers are coated with thermoplastic resin supplied by an extruder 9 when passing through the mold, and are then drawn into a line by a drawing machine 10 and cut by a cutting machine 11 to form reinforced pellets 12. Become. Here, 13 is a guide loaf. The outline of this invention is as follows, however, any of the known rovings obtained by consolidating several tens to hundreds of single fibers using a consolidating agent is applicable to the present invention. but preferably without a coupling agent,
It is obtained by concentrating fibers using consolidating agents, lubricants, etc.

In addition, the washing tank 8 is used to wash the dust collecting agent that has adhered to the roving in advance, and the cleaning liquid used here is one that can wash the dust collecting agent that has adhered to the roving in advance. Since water-soluble concentration agents are usually used, it is better to use water as the cleaning liquid. Further, the dryer 4 may be any type as long as it has the ability to dry the cleaning liquid. Further, instead of this washing step, the fibers may be heated to melt and remove the toning agent. The surface treatment tank 6 is preferably one in which the coupling agent contained therein does not cause rust, and the surface treatment liquid 5 may be one in which graphite is suspended in a coupling agent as described above.

The dryer 7 may be any type as long as it has the ability to dry the solvent contained in the surface treatment liquid.

It is sufficient that the mold 8 has a structure capable of covering a predetermined number of surface-treated fibers obtained through the above-described steps with the thermoplastic resin supplied from the extruder 9.

It is sufficient that the pulling machine 10 has the ability to take off the product obtained by the mold, and the cutting machine is sufficient as long as it can continuously cut a predetermined length.

The structure of the reinforced pellet obtained in this way will be explained with reference to the second diagram. 20 is a reinforced pellet, and the long fiber east 2
1 are disposed in the thermoplastic resin 22 over the entire length of this reinforced pellet almost parallel to the width direction. This long fiber is made up of tens to thousands of vertical single fibers coated almost on the circumference with a coupling agent and dotted with graphite. It is necessary to place more than a bundle inside the reinforced pellet. Next, referring to FIG. 8, which is a partially enlarged view of the long fiber east, the structure of the above-mentioned single fibers will be explained. 30 is a single fiber, 31 is a coupling agent, and 32 is graphite. Next, to explain the raw materials that are the starting materials for the reinforced pellet obtained by the method of this invention, the types of single fibers that are the constituent elements of the long fiber east are as follows: When placed inside the reinforced pellet as the long fiber east, Any fiber that can improve mechanical strength, especially tensile strength, flexural strength, and tensile modulus, can be used; typical examples include glass fiber, carbon fiber, aromatic amide fiber, and phenol. fibers, asbestos fibers, cellulose fibers, jute (hemp) fibers, sisal fibers, etc., and preferably glass fibers and carbon fibers. As explained above, the coupling agent should be one that strengthens the interfacial bonding force with the thermoplastic resin when applied to the fibers compared to the different bonding force between the fibers and the thermoplastic resin. Although any of these coupling agents can be used in the present invention, typical examples of these coupling agents are boron-based coupling agents, milan-based coupling agents, and organic coupling agents, with silane-based coupling agents being preferred. Furthermore, any graphite having a granular appearance can be used in the present invention, and preferably has a particle size of one peak or less.
Hereinafter, the method of this invention will be specifically explained with reference to Examples.

(Example 1) Eight bundles of glass rovings made by converging 800 single glass fibers were assembled in advance as shown in the first diagram, washed with water in a washing tank, and then passed through a dryer maintained at 300 o'clock for 1 minute. Dried with 8.4 methanol, 9.6 ml of ion-exchanged water, 8-(3.4 epoxycyclohexyl)
After blending 10 pieces of ethyltrimethoxysilane and 2 pieces of graphite and then uniformly treating the surface with a surface treatment solution obtained, a reinforced pellet was obtained as shown in the first diagram.

The thermoplastic resin used here was a nylon 66 molding material, and the glass fibers accounted for 3 parts by weight in the weight parts of the reinforced pellet 10.

The reinforced beret has an outer diameter of 3 ribs and a length of 7 ribs. (Example 2) As a surface treatment liquid, a mixture of 8.4% methanol, 9.6% ion-exchanged water, 8% N-8(aminoethyl)-y-aminopropyltrimethoxysilane, and 2% graphite was used. However, in the same manner as in Example 1 except that polybutylene terephthalate was used as the thermoplastic resin,
A reinforced beret with a similar shape was obtained.

(Example 3) As a surface treatment liquid, 84% of methanol and 9% of ion-exchanged water were used.
．． 6 So, y-glycidoxyto. Propyle. Trimethoxy. A reinforced pellet having the same shape was obtained in the same manner as in Example 1, except that a mixture of 100 g of silane and 3 female graphite was used.

(Comparative Examples 1 and 3) After mixing 66 nylon molding material and chopped short glass fibers, the mixture was extruded using an extruder, taken off using a take-off machine, and then cut using a cutting machine to obtain reinforced pellets.

The glass fiber content and the shape of the reinforced pellets are as in Example 1.
I made it the same as (Comparative Example 2) A reinforced pellet with the same shape was obtained using the same compounding ratio and method as in Comparative Example 1, except that a polybutylene terephthalate molding material was used.

Test pieces were made from the reinforced pellets obtained in Examples 1 to 3 and Comparative Examples 1 to 3 using an injection molding machine at an injection speed of 2 seconds and an injection pressure of 800k9/uniform, and ASTM-
Tensile strength was measured individually according to D638, and bending strength was measured according to ASTM-D790.

The results are shown in Table 1 below.

Table 1 As is clear from the foregoing, the method of the present invention provides a method for manufacturing reinforced pellets with extremely high work efficiency through continuous operation.

Furthermore, as is clear from Table 1 above, the method of the present invention does not use a fiber concentration agent and arranges the concentrated fibers along the entire length of the reinforced pellet, so the mechanical properties of the reinforced pellet, especially A method is provided for improving important tensile and flexural strength.

[Brief explanation of the drawing]

FIG. 1 is a manufacturing schematic diagram of the present invention, FIG. 2 is a perspective view showing one embodiment of a reinforced pellet obtained by the manufacturing method of the present invention, and FIG. FIG. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 or more fiber rovings are washed with a liquid or heated to remove the sizing agent, and after surface treatment with a surface treatment liquid containing at least a coupling agent and graphite suspended in a solvent, the surface is treated with a mold. A method for producing reinforced thermoplastic resin pellets, which comprises coating the treated roving with thermoplastic resin, taking it with a take-off machine, and cutting it with a cutting machine.