JPH0623745A - Mixture of long-fiber-reinforced resin pellet and low-fiber-content pellet - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a resin molding pellet which is capable of obtaining a highly reliable resin molded product with little variation in quality. [Constitution] In a mixed raw material composed of long fiber reinforced resin pellets and a low fiber content pellet having a fiber content smaller than the long fiber reinforced resin pellets, the fiber content of the long fiber reinforced resin pellets and the average fiber content of the mixed raw materials Difference of 50
2% or more, which is less than or equal to% by weight, the pellet length of the long fiber reinforced resin pellets is 5 mm or more and 15 mm or less, and the pellet length of the low fiber content pellets is 1/2 or more of the pellet length of the long fiber reinforced resin pellets. A mixture of long fiber reinforced resin pellets and low fiber content pellets, which is made up of the above pellets and has a small variation in the fiber content depending on the molding quantity of the resin molded product.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a long fiber reinforced resin pellet having a large fiber content, an unreinforced resin pellet having a fiber content smaller than that of the long fiber reinforced resin pellet, or a fiber reinforced resin pellet having a small fiber content. (Hereinafter, referred to as "low fiber content pellets".) When using a raw material mixed, injection molding, extrusion molding, etc., strength,
A long fiber reinforced resin that can provide a molded product with little variation in mechanical properties such as elastic modulus, thermal properties such as thermal conductivity and coefficient of thermal expansion, and various physical property values such as fiber content and specific gravity. It relates to a mixture of pellets and low fiber content pellets.

[0002]

2. Description of the Related Art Commercially available short fiber reinforced resin compounds today are produced by kneading molten resin and reinforcing fibers with an extruder.
Although the pellet manufacturing process is performed to form the pellets, there are problems in this pellet manufacturing process such as breakage of fibers and difficulty in high packing.

In order to solve such a problem, a method of infiltrating a molten thermoplastic resin into long fibers and cutting the long fibers (Japanese Patent Publication No. 43-7448 and Japanese Patent Publication No. 44-16).
No. 793, Japanese Patent Publication No. 63-37694), or pellets formed by a pull-through method in which a continuous reinforcing filament bundle impregnated with and coated with a thermoplastic resin is cut into a predetermined length. A method for obtaining a structure (Japanese Patent Publication No. 63-252724), and further, a resin sheet is impregnated with a resin to prepare a composite sheet, which is cut and pelletized, and then pressed into a mold to be molded. There is a method (Japanese Patent Laid-Open No. 3-30916).

In addition, as the currently marketed products,
"VERTON" (trade name) of ICI, UK, "CELLSTRAN" (trade name) of Polyplastics Co., Ltd., "MTC-TPCM (LFP)" of Mitsui Toatsu Chemicals, Inc.
(Product name) and so on.

[0005]

However, in the method for producing long fiber reinforced resin pellets described in JP-B-43-7448 and JP-B-63-37694,
Since the continuous reinforcing filament bundle is impregnated and covered with a thermoplastic resin, the wettability between the filament and the resin is poor, and it is difficult to obtain a molded product having a uniform fiber distribution. If the content is high, the screws will be sheared at the time of contact between pellets, when the hopper of the injection molding machine is put in, or when the resin is not plasticized and melted in the cylinder of the injection molding machine. Moreover, there is a problem that the fibers fall off, and as a result, the expected mechanical properties cannot be obtained.

On the other hand, in the case of the method for producing long fiber reinforced pellets using the fiber-impregnated mat as a raw material, as described in JP-A-3-30916, dropping of the pellets can be prevented, but the production thereof The process is Sho 63-2
In the case of the pultrusion method described in Japanese Patent No. 52724, only the drawing / cutting process is mainly performed, whereas in the method described in Japanese Patent Laid-Open No. 30916/1993, production of a mat, impregnation of resin, cutting and molding. Etc., the manufacturing process is very complicated, and unlike the case of manufacturing by the pultrusion method, the fibers are not necessarily oriented in the longitudinal direction of the pellets, so at the time of pelletizing, The fibers have an orientation distribution. For this reason,
Although the wettability between the filament and the resin is excellent, the mechanical properties are equal to or less than those when manufactured by the pultrusion method.

By laminating continuous fiber reinforced resin sheets in which the fibers are aligned in one direction instead of a randomly oriented mat and heating and compressing to form a unidirectional fiber reinforced resin molded product, it is cut into a predetermined shape. The long-fiber-reinforced thermoplastic resin pellets produced have excellent wettability and the fibers are easily dispersed uniformly, so that it is possible to provide a molded product having extremely excellent physical properties and quality.

However, like the long-fiber-reinforced resin pellets made of the above-mentioned mat as a raw material, there is a problem that the manufacturing cost becomes very large because the manufacturing process becomes complicated.

For this reason, as a method of making it possible to provide it at a price similar to that of the pultrusion method, a method of extremely increasing the fiber content of the long fiber reinforced resin pellets may be used.

In the method for producing long-fiber-reinforced resin pellets based on a sheet, resin impregnation is relatively good,
It is possible to manufacture pellets having a high fiber content of 70 to 80% by weight or more, which is difficult to manufacture by the plutotrusion method (manufacturing is possible if imperfection is poor).

Usually, the fiber content of the fiber-reinforced resin pellets used for injection molding is often set to 30 to 40% by weight from the viewpoint of moldability and appearance quality, and the non-reinforced resin may have some rigidity. Pellets with a relatively low fiber content of 10 to 20% by weight are also used for application purposes.

Therefore, a method for obtaining a molded article having a predetermined fiber content by mixing unreinforced resin pellets with long fiber reinforced pellets having a very high fiber content,
That is, if the masterbatch method is used, the cost can be significantly reduced.

For example, if the cost of the non-reinforced resin pellets is significantly lower than the cost of the long fiber reinforced resin pellets, if the mixing ratio of the non-reinforced resin pellets and the long fiber reinforced resin pellets is n: 1, the unit The cost per weight can be reduced to about 1 / (n + 1).

Although such a cost reducing method can be applied to any pellet manufacturing method, it is particularly suitable for a sheet-based long fiber reinforced resin pellet manufacturing method capable of manufacturing pellets having a high fiber content.

By the way, various characteristics such as strength and elastic modulus of the molded product molded using the long fiber reinforced resin pellets are generally larger than those of the molded product molded using the short fiber reinforced resin pellets having the same fiber content. Although excellent, the variation in the physical property values is often larger than when the short fiber reinforced resin pellets are used.

Therefore, in the case of reliability design, although the molded product molded using the long fiber reinforced resin pellets is superior in average strength to the molded product molded using the short fiber reinforced resin pellets. In consideration of variations, the short fiber reinforced resin pellets are often less likely to cause defects. In addition, the variation in quality and physical properties of molded products is a master batch method in which long fiber reinforced resin pellets with high fiber content and non-reinforced resin pellets are mixed compared to the case of using a single pellet with a predetermined fiber content. Seems to be generally larger when using.

The molded product molded using the long fiber reinforced resin pellets has very excellent average values, but its merit is not utilized because of the large variation. Therefore, there is an urgent need to reduce the dispersion of quality and physical properties of molded products in order to spread the long fiber reinforced resin pellets.

[0018]

SUMMARY OF THE INVENTION The present invention has been made by paying attention to the problems in the above-mentioned conventional techniques, and it is possible to reduce variations in molded articles molded using long fiber reinforced resin pellets produced by the masterbatch method. The aim is to provide molded products with excellent reliability and excellent quality by reducing it.In addition, in the case of a resin with high material cost, in-process recycling is necessary, but recycled materials have physical properties. Since it is somewhat inferior, it is necessary to recover the physical properties, and the present invention is intended to use long fiber reinforced resin pellets as a recovery material.

[0019]

The present inventor has made diligent studies in view of such circumstances, and as a result, the variation in molded articles molded using long fiber reinforced resin pellets is mainly due to the following three factors. Therefore, when the masterbatch method is used, it was found that the improvement of the factors is particularly important, and the present invention was completed.

In other words, the cause of the variation is as follows: The manufacturing method of the long fiber reinforced pellets ...
When producing long fiber reinforced resin pellets, voids are generated between fibers unless the fiber bundle is sufficiently impregnated with resin. If the fibers are not sufficiently opened at the time of molding, these voids will be directly introduced as defects in the molded product. This factor depends mainly on the resin impregnation method, resin selection, and fiber aggregation.

Factors: Caused by molding conditions: In order to take full advantage of the long fiber reinforced resin pellets, the molding conditions are often set so that the fibers are not easily cut. However, the conditions under which the fibers are unlikely to break are also conditions under which the fibers and fiber bundles are difficult to uniformly disperse in the molded product, and the variation essentially increases.

For example, if the screw rotational speed of the injection molding machine is set to a large value, the average value of the static strength decreases, but the variation decreases, so that the reliability may be improved in total consideration.

Factors: Caused by mixing of a plurality of pellets ... In the masterbatch method, a long fiber reinforced resin pellet having a large fiber content and a non-reinforced resin pellet are mixed to obtain a molded article having a desired fiber content. It has gained. Therefore, if the mixed state of the pellets is not uniform, the fiber content of the molded product itself fluctuates greatly. This is a factor that need not be taken into consideration when using a single long fiber reinforced resin pellet having a fiber content equal to that of the molded product.

In the masterbatch method, long-fiber-reinforced resin pellets are often mixed with normal-grade non-reinforced resin pellets mainly for cost reasons. It does not have to be pellets and may be reinforced with chopped fibers or may be long fiber reinforced resin pellets having different fiber contents. Needless to say, the pellets may contain various fillers.

By the way, it is a well known fact that variations in various characteristics occur due to non-uniformity of mixing when mixing two or more types of pellets.
Mixers have been invented and devised. Even in the production of long-fiber-reinforced resin pellets using the masterbatch method, it is a fact that the mixing methods and mixers that have been invented and devised so far contribute to some improvement in characteristics. However, in injection molding using long fiber reinforced resin pellets using the masterbatch method, it is the multiple pellets that the previous inventions and inventions are trying to improve that influences the variation in various characteristics of the molded products. It was found that it was not due to non-uniformity in the pre-mixing process.

When the change in the tensile strength of the test piece is examined in the order of molding, the tensile strength often changes regularly.
Moreover, it has been found that this change has several tens of test pieces as one cycle. Therefore, when the relationship between the number of test pieces required for one cycle and the molding process was examined, it was found that the feeding interval of the raw material and one cycle of the strength change were substantially the same.

The variation in tensile strength is also related to the length of the long fiber reinforced resin pellet, and the variation increases as the pellet length increases.

Further, it was found that a condition in which the variation becomes large is a case where a molded product having a fiber content slightly smaller than the fiber content of the long fiber reinforced resin pellets is obtained.

From the above test results, the present inventor
Factors for increasing variations in various properties of long fiber reinforced resin pellets using the masterbatch method were estimated as follows.

In ordinary mixing of short fiber reinforced resin pellets, if uniform mixing can be obtained in the premixing process of pellets, the degree of non-uniformity generated in the hopper charging step is very high as shown in FIG. 1 (a). small.

However, when the long fiber reinforced resin pellets having a large pellet length and the low fiber content pellets having a small fiber length are mixed, even if they are uniformly mixed in the preliminary mixing stage,
The ideal state as shown in FIG.
In reality, as shown in (c) of FIG.

When the normal short fiber reinforced resin pellets pass through the hopper, they are fed in a uniform mixed state as shown in FIG. 2 (a), but when the fiber length becomes large, it becomes as shown in FIG. 2 (b). As shown, the long fiber reinforced resin pellets cause hopper bridges, and the low fiber content pellets having a small pellet length preferentially fall into the molding machine through the voids formed by the long fiber reinforced resin pellets. Therefore, the variation increases as the pellet length of the long fiber reinforced resin pellet increases.

When the fiber content of the desired molded article is much smaller than the fiber content of the long fiber reinforced resin pellets, the quantity ratio of the long fiber reinforced resin pellets and the low fiber content pellets becomes very large. That is, the number of pellets with a low fiber content is very large compared to the number of pellets of a long fiber reinforced resin. As a result, most of the pellets that pass through the hopper mouth are pellets with a low fiber content, so hopper bridging is less likely to occur, and since the voids between the pellets are reduced, the variation in fiber content of the molded product is reduced. Inevitably, variations in various characteristics caused by the difference in pellet shape should be reduced.

Since the low fiber content pellets preferentially fall into the molding machine, the fiber content of the molded product immediately after the raw material is charged is often smaller than the desired fiber content. Get closer to the rate. Further, just before the raw material is exhausted, the low fiber content pellets having a small size are in an insufficient state, so that the fiber content of the molded product becomes very large as shown in FIG. 1 (c).

Therefore, the strength and elastic modulus of the molded product immediately after the introduction of the raw materials are generally small, and increase as the molding quantity increases. Then, one cycle is completed when the raw material is used up, and the next one cycle is started by feeding the raw material again.

Therefore, the influence of the uniformity of pellets in the premixing stage on the quality variation of the molded article is relatively small.

Based on the above consideration, the present invention prevents the low fiber content pellets from being preferentially supplied into the molding machine through the voids formed by the long fiber reinforced resin pellets. Therefore, it was decided to solve the problem by making the pellet length of the low fiber content pellet larger than usual.

However, by simply increasing the pellet length of the low fiber content pellets, the excellent mechanical properties and the effect of reducing dispersion, which are the advantages of the long fiber reinforced resin pellets, cannot be obtained at the same time.

The pellet length of the long fiber reinforced resin pellet is
When the effect of increasing the fiber length in the molded product is emphasized, it is preferably 5 mm or more, and from the viewpoint of preventing hopper bridge, it is necessary to be 15 mm or less.

On the other hand, the low fiber content pellets have long fiber reinforced resin pellet lengths in order to prevent them from preferentially passing through between the bridged long fiber reinforced resin pellets and the voids formed by the long fiber reinforced resin pellets. 1/2
It is necessary to have the above pellet length.

Further, in order to obtain the variation reducing effect by the combination of the long fiber reinforced resin pellets having the above pellet length and the low fiber content pellets, the following conditions must be satisfied.

That is, the difference between the fiber content of the long fiber reinforced resin pellets and the average fiber content of the mixed raw materials (raw material obtained by mixing the long fiber reinforced resin pellets and the low fiber content pellets) is 5
It should be 0% by weight or less. When the difference between the fiber content of the long fiber reinforced resin pellets and the average fiber content of the mixed raw material is very large, for example, when the difference of the fiber content exceeds 50% by weight, the mixed raw material contains a relatively small amount of high fiber content. In this state, a large amount of low fiber content pellets are mixed with the long fiber reinforced resin pellets. In this state, the number of long-fiber-reinforced resin pellets is overwhelmingly smaller than the number of low-fiber-content pellets, and therefore there is little possibility that voids will be formed due to the presence of the long-fiber-reinforced resin pellets.
In addition, the proportion of the long fiber reinforced resin pellets in the pellets passing through the hopper mouth is extremely reduced, so that bridging is unlikely to occur.

Even in the case of a molded product molded using the raw materials mixed under such conditions, there is a large variation in quality. This is because the long fiber reinforced resin pellets having a high fiber content occupy a small proportion of the total number of pellets, and thus the fiber content fluctuates greatly if the mixed state of the long fiber reinforced resin pellets is not appropriate. However, the variation in the quality of the molded product due to such factors depends on the mixing state in the pre-mixing stage and is not a region where the present invention can be solved, so that the fiber content of the long fiber reinforced resin pellets and the mixing ratio The case where the difference in fiber content of the raw materials exceeds 50% by weight is not covered by the present invention.

In the present invention, the resin constituting the long fiber reinforced resin pellets, particularly the thermoplastic resin, is, for example, a polyolefin resin such as polyethylene or polypropylene, a polyester resin such as polyethylene terephthalate or polybutylene terephthalate, or a polyamide 6.
6, polyamide 6, polyamide 12, polyamide 46,
Polyamide resins such as polyamide 11 and polyamide 610, general-purpose resins such as AS resin, ABS resin, and polycarbonate, and further polyphenylene sulfide, polyether sulfone, polyetherimide, polyamideimide, polyetherketone, polyetheretherketone , Heat-resistant engineering plastics such as polyallyl ether ketone, polyether nitrile, thermoplastic polyimide, polyketone sulfide, and polysulfone, or super heat-resistant engineering plastics can be used.

The reinforcing fiber is not particularly limited as long as it has an elastic modulus higher than that of the matrix resin, and examples thereof include glass fiber, carbon fiber, ceramic fiber, mineral fiber and the like. Inorganic fiber, stainless steel, brass, metal fiber such as nickel, polyacrylonitrile fiber, cellulose fiber, polyphenylene benzothiazole fiber, polyethylene terephthalate fiber,
Examples include organic fibers such as liquid crystal aromatic polyester fibers, polyvinyl alcohol fibers, and aromatic polyamide (aramid) fibers.

In addition, various stabilizers and fillers such as flame retardants, antioxidants, ultraviolet absorbers, lubricants, colorants, and heat stabilizers are added within a range that does not impair moldability and mechanical properties. May be.

More specifically, as the filler, calcium carbonate, zinc oxide, magnesium oxide, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, talc, silicic acid, calcium silicate, mica, glass, glass balloon, quartz balloon , Inorganic powder such as graphite, boron, alumina, silicon carbide, boron carbide, boria, boron nitride, silicon nitride, aluminum nitride, silica, beryllium, beryllium oxide, asbestos, potassium titanate, carbon, graphite, boron, alumina, carbonization Inorganic whiskers such as silicon, boron carbide, boria, quartz, silica, beryllium, and boron nitride, aramid pulp, microcellulose, thermosetting resin powder, and the like. As the release agent and the inorganic filler,
There are lower alcohol esters of higher fatty acids, polyhydric alcohol esters of fatty acids, liquid paraffin, barium sulfate, shirasu, antimony oxide, etc. Other crystallization accelerators are alkylene glycol derivatives, polyalkylene glycol derivatives, ionomers, mica, titanium dioxide. Etc.

As a method for producing long fiber reinforced resin pellets, known production methods can be arbitrarily used,
For example, a method for producing long fiber reinforced resin pellets based on a pultrusion method such as an electric wire coating pellet method or a melt impregnated pellet method, or a mat made of fibers as described in JP-A-3-30916. After impregnating with resin, cutting and molding to make pellets, or prepreg sheets, preferably prepreg sheets containing unidirectionally oriented continuous fibers, are laminated on [0 °] x (x is determined by the plate thickness) After that, a method of pelletizing by cutting so that the orientation direction of the fiber coincides with the longitudinal direction of the pellet may be adopted, and the melt-spun thermoplastic resin and the above-mentioned fiber used for reinforcement may be used by a known method. A method of pelletizing by heating to a temperature above the melting temperature of the thermoplastic resin and performing roller compression after mixing to obtain a mixed fiber It may be.

The low fiber content pellets to be mixed with the long fiber reinforced resin pellets produced by the known production method may contain fibers and fillers, but if non-reinforced resin is used, it is cost effective. Is advantageous to It is an object of the present invention and a means for achieving this object to reduce the dispersion of various properties of molded articles by optimizing the pellet length of low fiber content pellets mixed with long fiber reinforced resin pellets. .

Although the variation improving margin according to the present invention varies depending on the premixing method, the premixing method is particularly limited because a clear variation reducing effect can be obtained by any of the premixing methods. Not a thing.

Examples of the premixing method include a method using a Henschel mixer, a super mixer, a V type blender, a ribbon blender and the like.

[0052]

In the mixture of the long fiber reinforced resin pellets and the low fiber content pellets according to the present invention, the pellet length of the long fiber reinforced resin pellets is set to 5 mm or more. Is increased to improve the mechanical properties, and the pellet length of the long fiber reinforced resin pellets is set to 15 mm or less.
Since the hopper bridge is easily prevented, the pellet length of the low fiber content pellets is set to be 1/2 or more of the pellet length of the long fiber reinforced resin pellets.
It becomes easy to prevent low fiber content pellets from preferentially passing through the voids formed between bridged long fiber reinforced resin pellets and through the voids formed by long fiber reinforced resin pellets. The difference in the average fiber content of the mixed raw material (raw material in which long fiber reinforced resin pellets and low fiber content pellets are mixed) is set to 50% by weight or less, which results in reduction in quality variation and is reliable. It becomes easy to provide a molded article having high properties.

[0053]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 E glass (SiO ₂ -Al _{2
O 3 -CaO-MgO-B 2} O 3 based glass) fibers (Total fineness: 67.5 tex, number of filaments: 400)
With a diameter of 40 mm-2 vent extruding machine at 400 ° C. (exit cross-sectional area: width 3.0 mm, thickness:
1.5 mm) and then polyether sulfone (UK ICI: "VICTREX" PES 4100G)
Was supplied from an extruder, melted and kneaded at 370 to 380 ° C., and while being extruded into a heating die, E glass fiber fused with polyethersulfone was pulled out at 10 m / min. The drawn product was run in a water tank to be cooled and solidified, and then cut to a length of 10 mm to obtain 50 wt% long glass fiber reinforced polyether sulfone resin pellets.

The long fiber reinforced resin pellets thus obtained and the polyether sulfone resin pellets which are low fiber content pellets (ICT, UK: "VICTRE")
X "PES 4100P (powder) was pelletized and the pellet length was cut to 7 mm) and blended so that the average glass fiber content of the mixed raw material would be 30% by weight, followed by hot air drying at 180 ° C for 5 hours, Mold clamping pressure 75T
Using an ON injection molding machine, a JIS No. 1 tensile and bending test piece having a thickness of 3 mm was molded at a cylinder temperature of 380 ° C. and a mold temperature of 200 ° C.

The mixed raw materials were charged with 20 test pieces as one charging amount (the same applies hereinafter).

The effects of the present invention were evaluated on the following items.

(1) Fiber content of test piece (determined by dissolving and drying resin with concentrated sulfuric acid, and then measuring fiber weight) (2) Tensile strength / tensile modulus (according to JIS K6911) ( 3) Bending strength / flexural modulus (according to JIS K6911) Evaluation results for each item of (1) to (3) are shown in FIGS. 3 to 7.

(Comparative Example 1) 50 wt% long glass fiber reinforced polyether sulfone resin pellets obtained by the same method as used in Example 1 and commercially available polyether sulfone resin pellets (UK ICI: "VICTR
EX "PES 4100G) was blended so that the average glass fiber content of the mixed raw material was 30% by weight,
Molding was performed under the same drying conditions and molding conditions as in Example 1 to obtain a test piece.

The evaluation results for the items (1) to (3) described in Example 1 are shown in FIGS.

(Evaluation Result 1) As shown in FIG. 3, in the case of Comparative Example 1, the fiber content was low at the beginning of molding and high at the latter stage of molding. Since the variation in modulus is large, there is a large variation in any of the tensile strength shown in FIG. 4, the tensile elastic modulus shown in FIG. 5, the bending strength shown in FIG. 6, and the bending elastic modulus shown in FIG. On the other hand, in the case of Example 1 of the present invention, as shown in FIG. 3, the change in the fiber content was small from the initial stage of molding to the latter stage of the molding, and the variation in fiber content was small. Therefore, the tensile strength shown in FIG. 4, the tensile elastic modulus shown in FIG. 5, the bending strength shown in FIG. 6, and the bending elastic modulus shown in FIG. 7 do not have such large variations as seen in Comparative Example 1, Highly reliable production with little quality variation It has been confirmed it is possible to obtain the goods.

(Example 2) A prepreg sheet of polyetheretherketone (UK ICI: APC-2, carbon fiber: AS4, 1 mm = about 8 plies) was used at [0 °].
₂₄ (24 plies in the 0 degree direction) stacked and (vertical) 250
mm × (width) 250 mm × (thickness) 3 mm Unidirectional carbon continuous fiber reinforced polyetheretherketone resin laminate (carbon fiber weight fraction: 67%) was prepared, and the laminate was cut to 10 mm × 3 mm × 3 mm long fiber reinforced resin rectangular solid pellets were obtained.

Polyether ether ketone resin pellets (ICI UK: "VICTRE") were added to the pellets so that the average carbon fiber content of the mixed raw material was 50% by weight.
X "PEEK 450P (powder) was pelletized and the pellet length was cut to 5 mm, 7.5 mm, and 10 mm) was dry-blended with a V-type blender, and a cylinder temperature was used using an injection molding machine with a clamping pressure of 75 TON: Three
JIS 1 with a thickness of 3 mm at 80 ° C and a mold temperature of 180 ° C
No. tensile and bending test pieces were molded.

FIGS. 8 to 10 show the measurement results of the variations for the items (1) to (3) described in Example 1.

(Comparative Example 2) Using the same method as in Example 2 for producing continuous fiber reinforced resin pellets made from a unidirectional carbon continuous fiber reinforced polyether ether ketone resin laminate, 67% by weight of continuous fiber reinforcement was used. Polyether ether ketone resin pellets were obtained.

Commercially available polyether ether ketone resin pellets (UK ICI:
VICTREX PEEK 450G) was mixed with V so that the average carbon fiber content of the mixed raw material was 50% by weight.
Dry blend using a mold blender and mold clamping pressure 75
Cylinder temperature: 380 using TON injection molding machine
C., mold temperature: 180.degree. C., and a JIS No. 1 tensile and bending test piece having a thickness of 3 mm was molded.

FIGS. 8 to 10 show the results of measurement of variations in the items (1) to (3) described in Example 1.

(Evaluation Result 2) As shown in FIG. 8, in the case of Comparative Example 2, since the fiber content varies greatly, the elastic modulus (tensile and bending elastic modulus) shown in FIG. 9 is obtained. While the variation in strength (particularly tensile strength) shown in FIG. 10 is considerably large, in the case of Example 2 of the present invention, the variation in fiber content is small as shown in FIG. Therefore, the elastic modulus shown in FIG. 9 and the strength shown in FIG. 10 do not have such a large variation as seen in Comparative Example 2, and it is possible to obtain a highly reliable molded product with little quality variation. It was confirmed to be possible.

(Example 3) 250 mm x 250 mm x 3 mm unidirectional mixed fiber laminate of polyether ether ketone and carbon fiber (Nitto Boseki Co., Ltd .: TEXXES hy)
bridge fabrics CWC 1013 D, 1
9 × 13 (COUNT / inch), carbon fiber weight: matrix weight = 150: 78, 1 ply thickness = 0.
13 mm) was manufactured under the following molding conditions.

That is, temperature condition: from room temperature to 400 ° C., about 1
Raise at 0 ° C / min, hold at 400 ° C for 30 minutes, 400 ° C
→ Temperature is lowered to about 10 ° C / min to room temperature Pressure condition: 0 to 60 minutes, 5 kg / cm ² , 60 minutes to 1
Up to 00 minutes, 15 kg / cm ² This unidirectional mixed fiber laminate was cut in the same manner as in Example 2 to produce long fiber reinforced resin pellets having a pellet length of 5 mm.

Polyetheretherketone resin pellets (“VICTREX” PEEK 450, manufactured by British ICI, Inc.) were added to the long fiber reinforced resin pellets thus obtained.
P (powder) is pelletized and the pellet length is 2.5m
m, cut into 5 mm) was dry blended using a V-type blender so that the average carbon fiber content of the mixed raw material was 50% by weight, and the above was carried out under the molding machine and molding conditions adopted in Example 2. The same test pieces as those in Examples and Comparative Examples were obtained.

Table 1 shows the evaluation results for the items (1) to (3) described in Example 1.

Comparative Example 3 Using the same manufacturing method as that used in Example 3, long fiber reinforced resin pellets having a pellet length of 5 mm were obtained. Example 3 in this pellet
Polyetheretherketone resin pellets having a pellet length of 2.0 mm produced by the same method as in Example 3 were dry-blended, and the same 50 wt% carbon long fibers as in Example 3 were used under the molding machine and molding conditions adopted in Example 2. A test piece made of a reinforced polyether ether ketone resin was obtained.

Table 1 shows the evaluation results for the items (1) to (3) described in Example 1.

(Evaluation result 3)

[Table 1]

As shown in Table 1, in the case of Comparative Example 3,
Since the variation in fiber content is large,
In contrast to the large variations in the strength and the elastic modulus, in the case of Example 3 of the present invention, the variations in the fiber content are small and the variations in the strength and the elastic modulus are small. confirmed.

(Examples 4 to 9) (Comparative Examples 4 and 5) In Examples 4 to 9 and Comparative Examples 4 and 5, 60 wt% glass long fiber reinforced polyamide 6 as long fiber reinforced resin pellets was used.
Using 6 resin pellets and 67 wt% carbon long fiber reinforced polyether ether ketone resin pellets, the relationship between the fiber content of the mixed raw material and the effect of improving dispersion was investigated.

(Examples 4 to 6) (Comparative Example 4) Long glass fiber reinforced polyamide 66 resin pellets (UK I
CI Company: "Verton" Grade: RF-700
-12: Polyamide 66 pellets in glass fiber weight fraction = 60% by weight (UK ICI: "Maranil")
A225 pellets were melted and kneaded again, and the pellet length was cut to 7 mm), and the mixed raw materials were blended so that the average fiber content was 5% by weight, 10% by weight, 30% by weight, and 50% by weight.

Using this mixed raw material, an injection pressure of 220
Using a TON injection molding machine, cylinder temperature: 310 ° C,
Mold temperature: JIS with a thickness of 3 mm under molding conditions of 100 ° C
A No. 1 tensile test piece was prepared.

FIG. 11 shows the calculation result of the Weibull coefficient concerning the tensile strength of 20 molded articles.

(Examples 7 to 9) (Comparative Example 5) Using the same manufacturing method as that used in Example 2, 67 wt% carbon long fiber reinforced polyether ether ketone resin pellets having a pellet length of 10 mm were prepared. It was made.

Polyetheretherketone resin pellets having a pellet length of 7 mm were added to the long fiber reinforced resin pellets (UK ICI: "VICTREX" PEEK 4).
50P (powder) is pelletized and the pellet length is 7m
m) was dry-blended so that the average fiber content of the mixed raw material was 10% by weight, 20% by weight, 30% by weight, and 40% by weight, and the same molding conditions as those adopted in Example 2 were used. A test piece was prepared.

FIG. 11 shows the calculation result of the Weibull coefficient concerning the tensile strength of 20 molded articles.

(Evaluation results 4 to 9) As shown in FIG.
In Comparative Examples 4 and 5, the Weibull coefficient was small and the variations in the tensile strength of the molded product were large, whereas in Examples 4 to 9 of the present invention, the Weibull coefficient was large and the variation in the tensile strength of the molded product was large. It was found to be small.

(Comprehensive Evaluation) As is clear from the above Examples and Comparative Examples, it can be understood that when the pellet length of the low fiber content pellets is increased, the variation in the physical property values of the molded product is reduced.

Further, Examples 4 to 6 and Comparative Examples 4 and 7
As can be seen from 9 to 9 and Comparative Example 5, when the difference between the fiber content of the mixed raw material and the fiber content of the long fiber reinforced resin pellet becomes large, the effect margin of the present invention gradually decreases. And
It can be seen that the present invention is obtained when the difference in fiber content is 50% by weight or less.

Further, as can be seen from the results of Example 3 and Comparative Example 3, when the pellet length of the long fiber reinforced resin pellets is 5 mm, it corresponds to 1/2 of the pellet length of the long fiber reinforced resin pellets. Although the effect can be seen from 2.5 mm, the effect margin is small compared to the case where the pellet length of the long fiber reinforced resin pellet is long (for example, Example 2). As a result, when the pellet length of the long fiber reinforced resin pellets is less than 5 mm, the voids formed by the long fiber reinforced resin pellets are very small, and the difference in pellet length of the low fiber content pellets does not affect the pellet length. It means that it will end up.

Therefore, the effective range of the present invention is that the pellet length of the long fiber reinforced resin pellets is 5 mm or more and 15 mm or less, and the pellet length of the low fiber content pellets is 1/2 or more of the pellet length of the long fiber reinforced resin pellets. In addition, the difference between the average fiber content of the mixed raw material and the fiber content of the long fiber reinforced resin pellets is 50% by weight or less.

[0089]

According to the present invention, the mixed raw material containing the long fiber reinforced resin pellets obtained as described above is used, and the long fiber reinforced resin pellets and the low fiber content ratio made of such mixed raw material are used. The use of a mixture of pellets as a molding raw material brings about a remarkably excellent effect that it is possible to provide a highly reliable molded product with little quality variation.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the influence of a pellet shape, a mixed state, and a fiber content rate.

FIG. 2 is an explanatory diagram showing changes in the fiber content of a molded product due to bridging of long fiber reinforced resin pellets.

FIG. 3 is a graph showing the results of examining the molding quantity dependency of the fiber content in Example 1 and Comparative Example 1 of the present invention.

FIG. 4 is a graph showing the results of examining the molding quantity dependency of tensile strength in Example 1 and Comparative Example 1 of the present invention.

FIG. 5 is a graph showing the results of examining the molding quantity dependency of the tensile elastic modulus in Example 1 and Comparative Example 1 of the present invention.

FIG. 6 is a graph showing the results of examining the molding quantity dependency of bending strength in Example 1 and Comparative Example 1 of the present invention.

FIG. 7 is a graph showing the results of examining the molding quantity dependency of flexural modulus in Example 1 and Comparative Example 1 of the present invention.

FIG. 8 is a graph showing the results of examining variations in the fiber content of 20 molded articles in Example 2 and Comparative Example 2 of the present invention.

FIG. 9 is a graph showing the results of examining the variation in elastic modulus of 20 molded products in Example 2 and Comparative Example 2 of the present invention.

FIG. 10 is a graph showing the results of examining the variation in strength of 20 molded products in Example 2 and Comparative Example 2 of the present invention.

FIG. 11 is a graph showing the results of examining the dependence of the Weibull coefficient concerning the tensile strength of 20 molded articles on the fiber content of the mixed raw material in Examples 4 to 9 and Comparative Examples 4 and 5 of the present invention.

Claims (1)

[Claims] 1. A mixed raw material comprising a long fiber reinforced resin pellet and a low fiber content pellet having a fiber content lower than that of the long fiber reinforced resin pellet, wherein a fiber content of the long fiber reinforced resin pellet and an average fiber of the mixed raw material. The difference in content is 50% by weight or less, the pellet length of the long fiber reinforced resin pellets is 5 mm or more and 15 mm or less, and the pellet length of the low fiber content pellets is 1/2 or more of the pellet length of the long fiber reinforced resin pellets. A mixture of long fiber reinforced resin pellets and low fiber content pellets, characterized in that it is composed of two or more types of pellets satisfying the conditions.