JPH02235613A - Manufacture of fiber reinforced thermosetting synthetic resin molding - Google Patents

Abstract

PURPOSE:To make material sizing unnecessary and enable automatic molding by molten-kneading a web-shaped material containing thermoplastic synthetic resin and fibrous substance of 3-100mm in length at a specified volumetric rate by a screw type kneading extruding machine, and obtaining a molding then. CONSTITUTION:A web-shaped material containing thermoplastic synthetic resin of 60-90vol.%, fibrous substance of 10-40vol.% and fibers of 3-100mm in length is introduced into a screw type kneading extruding machine equipped with a heating unit inside a barrel and/or screw, and molten-kneading them, and then the molten kneaded matters are supplied into a molding mold or injection mold, and thus obtaining a molding. Olefin resin of polypropylene, polyethylene, ethylene-propylene copolymer or the like, and amide resin of nylon 6, nylon 6-10 or the like are sued as thermoplastic resin. And,inorganic fibers of glass fiber, carbon fiber, boron fiber or the like as well as organic fibers of synthetic or natural fiber can also be used as a fibrous substance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a fiber-reinforced thermoplastic synthetic resin molded article. More specifically, the present invention relates to a method for producing fiber-reinforced thermoplastic synthetic resin molded products having excellent moldability, material loss, molding efficiency, etc.

[Conventional technology and its problems]

Materials for producing fiber-reinforced thermoplastic synthetic resin molded articles include so-called compound materials in which short fibers are kneaded into resin, and materials in which mats of long fibers are impregnated with resin.

Further, there is a composite material using fibers in the intermediate region (3 to ttx) as the fiber length. The compound material is supplied in the form of pellets, but the material is supplied in the form of a flexible web-like sheet due to its manufacturing method, or in the form of a plate-like sheet by melting the resin once and pressing it.

To obtain a molded product using the above-mentioned material in the form of a sheet, first the original sheet is cut according to the weight and shape of the molded product, and then this sheet is heated with an infrared heater, hot air heater, etc. The resin is molten, transferred onto a mold of a hot press machine, and press-molded to obtain a molded product.

However, this method K has the following problems.

a) The raw sheet must be cut and sized according to each individual molded product, making the process complicated and inefficient, and there is a lot of material loss due to the production of cut edges.

b) Sheets in a heated and molten state must be transported and dried, making handling complicated and difficult to automate.

C) Since the sheet in the heated and molten state remains in the ohnon state for a relatively long time, smoke, odor, etc. deteriorate the working environment.

[Means to solve the problem]

As a result of intensive studies aimed at solving all of the above-mentioned problems, the present inventors have developed a method for completely specifying a thermoplastic synthetic resin material in the form of a web containing all fibrous substances in a specific amount and length within a specific range. It was discovered that the object could be achieved by melt-kneading and molding, and the present invention was completed.

That is, the gist of the present invention is that thermoplastic synthetic resin 60-9
Q volume %, fibrous material / 0 = - uθ capacity ratio, and all web-like raw materials containing all fibers with a length of 3 to ioo The present invention relates to a method for producing a fiber-reinforced thermoplastic synthetic resin molded article, in which the melt-kneaded product is introduced, melt-kneaded, and supplied to a press mold or injection mold to obtain a molded product.

The thermoplastic synthetic resin that can be used in the method of the present invention includes:
Olefin resins such as polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-hinyl acetate copolymer, nylon 6, nylon 6-6, nylon A
-/0, amide resins such as nylon 7.2, ester resins such as polyethylene terephthalate and polybutylene terephthalate, styrene resins such as polystyrene and acrylonitrile-styrene copolymers, polyvinyl chloride, polyvinylidene chloride, etc. Examples include thermoplastic synthetic resins commonly used in extrusion molding and injection molding, such as vinyl chloride resins.

Among these, ole7-based resins are preferably used from the viewpoint of moldability, strength, etc.

As the fibrous material that can be used in the method of the present invention, in addition to inorganic fibers such as glass fibers, carbon fibers, metal fibers, whiskers, and pilon fibers, synthetic or natural organic fibers can also be used. Usually glass fiber or carbon fiber is used.

As the fibrous material, a material having a length of about 3 to 0.theta. and a thickness of about 3 to 50 W is preferably used.

In the present invention, the web-like raw material is defined as a fibrous material having a length of about 3 to 0 θ fins, preferably about 3 to 0 SO, a diameter of 50 or less, and an average particle size of 2 Contains the following granular thermoplastic synthetic resin (granular resin) {ijO-90 by volume, and the fibrous material has a thickness of 0. It has a structure in which granular resin is dispersed in an adhesive or non-adhesive state in the form of a pine-like, sheet-like, etc. (hereinafter referred to as a sheet-like) material of about 30 mm, and is breathable as a whole. It is made of metal and has enough flexibility and self-retention ability to be wound into a roll.

As a means to hold the shape of the fibrous material itself and the granular resin dispersed in the fibrous material, an adhesive of about θ, θ/~5% by weight is applied to the total amount of the granular resin and fibrous material. By applying heat to the granular resin dispersed in the fibrous material, a part (surface) of the granular resin can be bonded by using a fibrous material to bond the contact points between the fibrous materials or between the fibrous material and the granular resin, or by applying heat to the granular resin dispersed in the fibrous material. Means such as completely melting the fibrous material and bringing it into a state where the fibrous material intersects with the fibrous material and/or the fibrous material and the granular resin material are bonded is used.

As the above adhesive, for example, polyvinyl acetate, polyacrylic acid ester, synthetic rubber, carpoquin methylcellulose, dextrin, polyvinyl alcohol, starch, etc. are suitably used.

It is necessary that the ratio of the thermoplastic synthetic resin and the fibrous material constituting the entire raw material sheet in the form of a web is such that the fibrous material has a volume of /θ to lIo.

If the /O capacity is less than 11%, it will not serve as a reinforcement, and if it exceeds 1Io volume%, the fluidity of the molten material will decrease, which will be disadvantageous during molding.

Hereinafter, an example of the method of the present invention will be explained in more detail using the drawings.

FIG. 1 is a partial cross-sectional view of an example of an apparatus suitable for use in the method of the present invention.

In the figure, l is the raw material (web), c is the kneading machine, 3 is the heater, l is the accumulator, 5 is the valve, 6 is the conduit, 7 is the valve, g:, g' are the lower and upper molds. .

Raw material l is a thermoplastic synthetic resin with a capacity of 60 to 90 and a length of 3.
It is a web-like raw material consisting of a fibrous material of ~/00■/0-g θ capacity Q.

Since the web-like raw material 1 is flexible, it can be handled by being wound around a core as shown in the figure, and of course, it can also be handled as a sheet-like material cut into predetermined dimensions.

The web-shaped raw material is then sent to a screw-type kneader B equipped with a heater B, where it is melted and kneaded. It is preferable that the kneader has a structure in which a heater is also provided inside the screw.

If this melt-kneading is carried out too vigorously, the fibrous material will break, so light kneading is preferred, and the purpose is to melt, degas, pressurize, and uniformly disperse the resin in the raw materials/inside. For this reason, it is desirable to have a screw shape and rotation speed that provides a long residence time so that the material passes through the screw for at least /S seconds.

The molten and kneaded material may be sent as is to a press mold, etc., but as shown in the figure, it is best to pass through a valve and accumulate it in an accumulator for accurate metering and smooth delivery all at once. preferred above.

The molten kneaded material stored in the accumulator is supplied onto the lower mold g through the conduit 6. Preferably, the conduit 6 is flexible. This makes it possible to supply an arbitrary amount of the melt-kneaded material to an arbitrary position of the lower mold, and it is possible to handle molded products with large thickness changes. On the contrary, mold g, g
A similar effect can be obtained even if ' is moved so that it can be moved. The timing of supply to the mold is done at Nolf 7.

The figure shows a press mold g. Although g'+ is shown, it is also possible to place an injection mold here and perform injection molding.

In this case, the melted and kneaded material may be injected all at once from the accumulator tag and filled into the cavity of the injection mold.

In the case of injection molding, short length fibrous materials,
That is, it is preferable to use one having a length of less than /Owr, preferably less than 3 ms, from the viewpoint of dispersibility and the like.

The apparatus used in the method of the present invention is preferably a one-type accumulator, but it is a place where the screer retreats during kneading to accumulate the melted mixture at the tip of the cylinder, and the screier moves forward all at once to inject (extrude) the melted mixture. ．． A so-called screw in-line molding machine or the like can also be employed.

[Effects of the Invention] Since there is no need for processes such as sizing the original web-like raw material for each molded product, there is less occurrence of edge loss. In addition, it can easily handle molded products with changes in wall thickness, and the work is simple and easy. Since the heated sheets do not open, there are no problems with smoke, odor, etc. It is very effective in practical terms, such as the ease of automating the molding system.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a device suitable for use in the method of the present invention, partially in section. In the figure, l is the raw material (web), c is the kneading machine, 3 is the heater, Hiro is the accumulator, 5 is the bulb, 6 is the conduit, 7 is the bulb, and g and g' are the lower and upper molds, respectively.

Claims (1)

[Claims] (1) Thermoplastic synthetic resin 60-90% by volume, length 3-1
A web-like raw material containing 10 to 40% by volume of 00 mm fibrous material is introduced into a screw-type kneading extruder equipped with a heating device inside the barrel and/or screw to perform melt-kneading, and this melt-kneaded product is press-molded. 1. A method for producing a fiber-reinforced thermoplastic synthetic resin molded article, which comprises supplying a molded article to a mold or an injection mold to obtain a molded article.