JPH03179033A - Molding material and its mixture - Google Patents

Abstract

PURPOSE:To obtain a molding having good fiber dispersibility and high mechanical strengths in spite of containing a fibrous reinforcement in a high concentration by cutting a plate prepared by infiltrating a polybutylene terephthalate resin into a fibrous reinforcement composed of single fibers to form a molding material satisfying specified requirements and using this material. CONSTITUTION:A molding material 20 obtained by preparing a plate of a structure in which a fibrous reinforcement composed of single fibers (filaments) 22 is coated with a polybutylene terephthalate resin 21 (hereinafter referred to as the PBT resin), and the PBT resin is infiltrated into the fibrous reinforcement and cutting this plate filled with the fibrous reinforcement and satisfying the following requirements (1)-(5): (1) the filling ratio of the fibrous reinforcement in the molding material is 50-90wt.%, (2) the length of the fibrous reinforcement is 1-30mm, (3) at least one side (e.g. H) of the molding material 20 is at most 1mm, (4) the specific surface area of the molding material 20 is at least 20cm<2>/g, and (5) the melt flow rate of the PBT resin is 10-100g/10min when measured under conditions of 235 deg.C and 2.16kgf according to JIS K-7210.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to molding materials and mixtures thereof, and in particular to injection molding, extrusion molding, pressure 1i! The present invention relates to a molding material and a mixture thereof that can be used for molding, etc., and can provide a molded product with good dispersibility in molding, little fiber breakage, and significantly improved mechanical strength.

[Conventional technology]

Conventionally, methods for producing fiber-reinforced resin compositions can be roughly divided into the following two types.

■One method is to make a tri-blend product by tri-blending glass fibers with a length of, for example, about 3 an into polybutylene lenticulate resin (hereinafter simply referred to as PBT resin), and then kneading and granulating this with an extruder. This is the method to make it Berendt.

■Another method is to pass a continuous body such as glass fiber into the die hole, guide the P[l↑resin melted by an extruder into the die hole, cover the fiber material, and after cooling it to a certain length. This is a method to obtain a cylindrical molding material by cutting the material into cylindrical shapes.

[Problem to be solved by the invention]

In the former case, the upper limit of the glass fiber filling rate of the molding material obtained as described above has usually been set at 30% by weight due to problems with the dispersibility of the fibers during kneading. Also, in the latter case, the upper limit is usually set at 40% by weight due to the problem of fiber pull-out resistance within the die hole.

Therefore, there was a problem that it was not possible to obtain a molding material with a higher filling rate.

Furthermore, conventionally, resins used as molding materials generally have a high molecular weight, that is, a low melt fluororate (hereinafter abbreviated as rMFRJ), in consideration of the physical properties of the molded product after molding.
Therefore, in the former case, the fibers break due to the shearing force generated between the extruder barrel and screw during kneading, and the average fiber length in the resulting molding material is 0.3 to 0.
．． There was an issue with the length being shortened to 5m.

On the other hand, even in the latter case, the fiber length in the molding material is
Although it is the same as that of the molding material and is maintained for a long time, it has the above-mentioned low MFR, and the shape of the molding material is generally cylindrical, and the surface area of the molding material per unit weight, that is, the specific surface area is small, so it is difficult to feed it to an extruder. Because it takes time to plasticize the PBT resin in the zone, the fibers break during molding, which not only shortens the average fiber in the molded product to 0.3 to 0.5 m, but also causes the problem of poor fiber dispersion. Ru.

As described above, the prior art has the problem of not being able to fully demonstrate the reinforcing effect of fibers in terms of fiber filling rate, breakage, and dispersibility.

Therefore, the object of the present invention is to achieve good fiber dispersibility during molding despite being filled with a high concentration of fiber reinforcing material.
It is an object of the present invention to provide a molding material and a mixture thereof that allow a molded article with less fiber breakage and significantly improved fiber strength to be obtained.

[Means to solve the problem]

As a result of intensive studies to solve the above problems, the present inventor found that the problem of poor dispersion of m-fibers or fiber breakage that occurs in the extruder during molding is closely related to the MFR and specific surface area of the resin in the molding material. In addition, by setting these MFR and specific surface area to satisfy certain conditions, fiber dispersibility during molding is good, there is little fiber breakage, and mechanical reinforcement is significantly improved without impairing the physical properties of the molded product. The present invention has been completed based on the discovery that the present invention can be improved.

That is, the molding material according to the present invention is a plate-like body having a structure in which a fibrous reinforcing material made of single fibers (filaments) is covered with a PBT resin, and the PBT resin is impregnated into the fibrous reinforcing material. and cutting the plate-shaped body filled with the fibrous reinforcing material, (i) the filling ratio of the fibrous reinforcing material to the molding material is 50
% by weight or more and 90% by weight or less, (ii) the length of the fibrous reinforcing material is 1 to 30 m, (ii)
i) At least one side of the plate-like body is 1III11 or less, (
iv) The specific surface area of the molding material is 20 cm"/g or more. (v) The MFR of the PBT resin meets JIS K 7210.
Based on test temperature 235"C1 test load 2.16kgf
10 g/10 minutes or longer when measured under the conditions of
/10 minutes or less.

Further, the molding material mixture according to the present invention is composed of the above-mentioned molding material and a fiber-unreinforced PBT resin,
MFI of resin? is the PBT resin gate Fl? which is the molding material. 0.05 to 1 (fj (measured under the same conditions)).

The present invention will be explained in detail below.

First, an example of the molding material of the present invention will be explained based on FIGS. 1 and 2. In the figure, 20 is a molding material, 21 is a PBT resin, and 22 is a single fiber.

L is the length of the molding material, that is, the fiber length, and is 1.0 to 30
If m is less than 1.0 mm, the fiber length is short and a sufficient reinforcing effect cannot be obtained, whereas if it exceeds 30 am, bridging etc. occur in the hopper, making molding difficult, which is not preferable.

W and 11 are the width and thickness of the molding material, respectively, and are determined so that the specific surface area of the following formula is greater than or equal to a certain value.

LXlf Xll At least one of the lengths is 1. It is preferable to set the specific surface area to be less than Om+a, preferably less than 0.5 in order to set a large specific surface area.

In the present invention, the specific surface area is 20 cffl/g or more, preferably 30 crl/g, more preferably 40 cfl/g.
1! /g or more. If the specific surface area is less than 20cj/g, it will take a long time for the PBT resin in the molding material to reach a molten state in the extruder, especially during injection molding, extrusion molding, etc., resulting in poor fiber dispersion and poor fiber dispersion in the extruder supply zone. This is not preferable as it may cause problems such as fiber breakage.

Note that the thickness H is preferably set to 0.1 am or more from the viewpoint of classification in the hopper and ease of handling.

1lFfl of the PBT resin used in the present invention is JIS
Based on K7210, test temperature: 235°C, test load: 2.
When measured under the conditions of 16 kgf (hereinafter referred to as "measurement conditions of the present invention"), 100 g/10 for 10 g/10 minutes or more
minutes or less. If it exceeds 100 g/10 minutes, the 111 mechanical strength of the obtained molded product will be significantly reduced, which is not preferable.

Further, if it is less than 10 g/10 minutes, it is not preferable because poor fiber dispersion during molding and fiber breakage occur, which impairs the reinforcing effect of the fibers. In general, the MFR of PBT resin is in the range of 5 to 120 g/10 minutes when measured under the measurement conditions of the present invention. That is, the inventor found a specific MFR range within the general MFR range in relation to other requirements of the present invention.

The types of fibrous reinforcing materials used in the present invention include glass fibers such as E-glass and S-glass, carbon fibers such as polyacrylonitrile, pitch, and rayon, and DuPont's "Kevlar" (trademark). Typical examples include aromatic polyamide fibers, silicon carbide fibers such as "Nicalon J (trademark)" manufactured by Nippon Carbon Co., Ltd., gold B fibers, etc. These fibrous reinforcing materials can be used alone or in combination.

In the present invention, the fiber diameter varies depending on the type of fiber, but for example, in the case of glass fiber, it is usually 5 to 25 μm, but from the viewpoint of mechanical properties, a thinner one is preferable, and it is not possible to surface-treat the fibrous reinforcing material. It is preferable from the viewpoint of adhesiveness with PBT resin, and for example, in the case of glass fiber, it is particularly preferable to treat it with a silane-based or titanate-based coupling agent.

In the present invention, the filling rate of the fibrous reinforcing agent in the molding material is
It is 50% by weight or more and 90% by weight or less. If it is less than 50 years old, the characteristic of high fiber filling, which is the effect of the present invention, cannot be exhibited, and it is also unfavorable from an economic point of view when used as a masterbatch, which will be described later. This is not preferable because the surface of the fiber cannot be sufficiently covered with the POT resin.

The molding material according to the present invention provides a plate-like body having a structure in which a fibrous reinforcing material made of single fibers (filaments) is covered with a PCT resin, and the PBT resin is impregnated into the fibrous reinforcing material. , is obtained by cutting the plate-shaped body filled with the 151i fibrous reinforcing material into a certain length.

In the present invention, the surface of 90% or more of the single fibers (filaments) that are the constituent units of the fibrous reinforcing material is
It is preferable to obtain a molded material 4 coated with BT resin.

In the present invention, the method of impregnating PBT resin into the fibrous reinforcing material and coating the surface of single fibers (filaments), which are the constituent units of fibers, with PBT resin is not particularly limited. Melt impregnation method for impregnating fibrous reinforcing material, suspending powdered PBT resin in the air,
Another example is a fluidized bed method in which the material is impregnated in a suspended state in a liquid such as water.

A typical example of the melt impregnation method is JP-A-61-229534.
No. 61mm229535, No.61mm22953
No. 6 and Japanese Patent Application No. 61216253.

An example of the melt impregnation method that can be employed in the present invention will be explained based on FIG. 3.

Ropings 2 of length til1ff drawn from a plurality of bobbins I are aligned in one direction by an aligner 3, and then passed through tension adjustment rolls 4.5.6 to form a fiber sheet 7. In addition to the fiber sheet aligned in one direction, multidirectional continuous fibers such as woven fabric can also be used in the present invention.

On the other hand, the extruder (not shown) heats and melts the resin into a die 8.
It is applied to the surface of the lower bell (10) heated by a heating roll 9. The upper bell 2 is heated by a heating roll 11.

Next, the seat 7 has a lower belt (10) and an upper belt (12).
It passes between the heated impregnating rolls 13 while being held under tension.

The continuous fiber/POT citrus composite 14 obtained in this way may be used as it is or, if necessary, after laminating and hot pressing the required number of sheets to obtain the desired thickness, the composite material 14 may be sliced in parallel with the fibers to a desired width. After slitting at step 18, the material is cut into a desired length in a direction perpendicular to the fibers [18] to obtain a rectangular molding material 20. In addition, in FIG. 3, 15 and 16 are rolls for take-up.

As the method of laminating and hot pressing, for example, the composite 1
The surface of PBT resin 4 is heated to a temperature above the softening point of the PBT resin and then laminated, or the composite 14 is heated to a temperature above the softening point of the resin in a heating furnace after lamination. The resin is cooled under pressure to a temperature below the solidification temperature of the resin.

The molding material thus obtained can be used as it is or by tri-blending with fiber-unreinforced PBT resin to obtain a desired fiber filling rate to obtain a molding material mixture and using it as a so-called masterbatch for injection molding. ,
Subjected to extrusion molding.

There are no particular restrictions on the blend ratio of the molding material and the non-fiber-reinforced PBT resin, and it should be determined by the set value of the fiber filling rate of the molded product obtained by molding the mixture.

The MFR of the fiber-unreinforced resin used in the present invention is the PBT resin MP in the molding material described above under the measurement conditions of the present invention.
It is 0.05 to 1 times R. If it exceeds 1 times, it is not preferable because the physical properties of the molded product will greatly deteriorate, and if it is less than 0.05 times, fiber dispersion in the molded product will be poor and fiber breakage will occur.
This is not preferable because the effects of the present invention cannot be exhibited.

Note that the above-mentioned molding material or molding material mixture can be applied to, for example, compression molding in addition to the above-mentioned injection molding and extrusion molding. When applied to this compression molding, the molding material has a plate-like shape, that is, a scale, so it adheres well to the mold, and because the specific surface area is large, the resin in the material melts quickly, which is faster than before. Molding can be done in a shorter time compared to the method. In this case, whereas conventional molding materials are usually cylindrical, the material is scale-like, and has the secondary effect of being easier to position on the mold.

〔Example〕

Examples of the present invention will be described below, but these examples are not to be interpreted in a 'FIIK' manner within the scope of the present invention.

Example 1 Using the apparatus shown in FIG. 3, a molding material was obtained from PBT resin and glass fiber in the following manner. PBT citrus (7)
? IFR c, test temperature 2 based on JIS K 7210
The weight was 58g and 710 minutes when measured at 35°C and a test load of 2.16kgf.

Glass fibers drawn from 100 bobbins 1 (Ia
After aligning 2100 noro hinks (Ii fiber diameter 13 μm, number of converged fibers 1600) in one direction with an aligner 3, they were passed through a tension adjustment roll 4.5.6 to form a fiber sheet 7 with a width of 200 mm.

On the other hand, PBT resin heated and melted at 250"C with an extruder (not shown) is passed through a die 8 to a lower belt roll 9 (
Here, two coats were coated to a thickness of 145 μm on the surface of the lower bell 0, which had been heated to 280°C (without heating at 9°).

Next, the sheet 7 is attached to the lower belt 0 and the upper belt 12 (2
It is heated to 280'C by the book top belt roll 11. Note that roll 11 is not heated. ) containing three pieces of wood with a diameter of 240M heated to 280℃ while being sandwiched between them. 50cm between i-rolls 13 while applying a tension of 115kg.
It passed at a speed of /min.

The glass fiber/PBT resin composite 14 thus obtained is cooled to lOOoC, and then transferred to the take-up roll 1.
5. After taking it in step 16, it is slit at 5-width intervals with a slitter 17, and then cut into 3-width lengths with a cutter 18 to form a molded material 4 with a thickness of 0.24 m and a glass fiber filling rate of 70% by weight.
I got it.

The specific surface area of the obtained molding material was found to be 57C/
It was g.

Next, $443 parts by weight of the molding material and 57M parts of non-fiber-reinforced PBT resin (PR = 8 g, 710 minutes) were dry-blended to obtain a mixture of molding materials, and a glass fiber filling rate of 30 was obtained using an injection molding machine. A molded article of % by weight was created.

When the cross section of the molded article was observed using a scanning electron microscope, the dispersibility of the fibers was good and no phenomena such as blocking were observed.

Is there an eye shift using the molded product? 41 impact strength and average fiber length were measured. The results are shown in Table 1.

Compared to conventional products, there is less fiber folding during injection molding, and the Izot impact strength has also been greatly improved.

Example 2 A molding material with a fiber filling rate of 50% was obtained in the same manner as in Example 1, except that the thickness of PBT citrus applied to the belt was changed to 210 μm. Then, the obtained molding material was molded as it was in the same manner as in Example 1 to obtain a molded product with a fiber filling rate of 50%.

When the cross section of the molded article was observed using a scanning electron microscope, the dispersibility of the fibers was good and no phenomena such as blocking were observed. In addition, Izot impact strength and average fiber length were measured using the molded product. The results are shown in Table 1.

Comparative Example 1 A molding material with a glass fiber filling rate of 70% by weight and a specific surface area of 57 cffl/g was prepared in the same manner as in Example 1, except that PBT citrus with an MFR of 8 g/10 minutes under the measurement conditions of the present invention was used. I got it.

Next, 43 parts by weight of the molding material and 57 parts by weight of the non-fiber-reinforced PBT resin used in Example 1 were tri-blended to obtain a molding material mixture, and molded using an injection molding machine with a glass fiber filling rate of 30% by weight. created a product.

When the cross section of the molded article was observed using a scanning electron microscope, the dispersibility of the fibers was insufficient and no phenomena such as protonation were observed.

In addition, Izot impact strength and average fiber length were measured using the molded product. The results are shown in Table 1.

Compared to Example 1, fiber breakage during injection molding was severe;
Izotsu impact strength also decreased significantly.

Comparative Example 2 A PBT resin (the same resin used in Example 1) melted by an extruder was fed into a crosshead die having a hole with a diameter of 3flII+ and a length of 300M.

On the other hand, the seven glass fibers used in Example 1 were passed through the perforations and brought into contact with the molten PBT resin while passing through a crosshead heated to 280'C to coat the fibers with the resin.

Then, after cooling to below 100"C and taking it away, the length of 3
Cut into 11 pieces, diameter 3, glass fiber filled, visibility 4
A molding material having a cylindrical shape of 0% by weight was obtained. The specific surface area of the molding material obtained was determined to be 13 aJ/g.

Next, the obtained molding material was triblended as shown in Table 1, and then a molded product with a glass fiber filling rate of 30 to 1 ffi% was produced using the injection molding machine used in Example 1. When the cross section of the molded article was observed using a scanning electron 8Ji microscope, the dispersibility of the fibers was insufficient and phenomena such as blocking were observed.

Also, using the molded product, Izotsu NJi%? Strength and average fiber length were measured. The results are shown in Table 1.

Compared to Example 1, fiber breakage during injection molding was severe, and as a result, the Izot impact strength was also significantly reduced.

Examples 3 to 4 In Example 1, instead of the PIIT resin shown in Table 1,
1) A molding material was prepared in the same manner as in Example 1. Then, after tri-blending with fiber-unreinforced PBT resin in the proportions shown in Table 1,
The molded products shown in Table 1 were obtained by molding.

Izot impact strength and average fiber length were measured using the molded product. The results are shown in Table 1.

Comparative Example 3 A molding material was obtained in the same manner as in Example 1, except that the PBT resin shown in Table 1 was used in Example 1. Next, the mixture was triblended with non-fiber-reinforced PBT resin in the proportions shown in Table 1, and then molded to obtain the molded products shown in Table 1.

Izot impact strength and average fiber length were measured using the molded product. The results are shown in Table 1.

Example 5 The molding material obtained in Example 1 was triblended with a non-fiber-reinforced PBT resin to adjust the fiber filling law to 30%. This triblend product was molded into a round bar with a diameter of 30 fflIllφ using a conventional extrusion molding machine.

When the cross section of this molded article was observed using a scanning electron microscope, the dispersibility of the fibers was good and no phenomena such as blocking were observed.

Example 6 Mold release agent (FREKOTE44; American FREKOTE)
After placing 300 g of the molding material 20 obtained in Example 1 uniformly in the female mold 30 shown in FIG. .

Next, the mold was left in a heating furnace heated to 260°C until the mold temperature reached 240°C, and then quickly transferred to a compression molding machine equipped with a pressure plate at room temperature and subjected to a pressure of 50 kg/cJ for 20 minutes. Press 300x 300x 2. Om+
A molded article of s was obtained.

When the surface of the molded product was visually observed, it was found that the fibers were well dispersed without any fibers protruding from the surface, and the molded product had good surface gloss.

〔Effect of the invention〕

According to the present invention, despite being filled with a high concentration of fiber reinforcing material, the molded product has good fiber dispersibility during molding, less fiber breakage and breakage, and significantly improved mechanical strength. A molding material and a mixture thereof can be provided.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the structure of the molding material of the present invention;
Fig. 2 is a partially enlarged view of the molding material, Fig. 3 is a schematic diagram showing an example of an apparatus for manufacturing the molding material of the present invention, and Fig. 4 is an example of a mold for compression molding to which the present invention is applied. FIG. 20: Molding material 21: Polybutylene terephthalate resin 22: Single fiber can 30: Female mold 31: Male mold

Claims (1)

[Claims] 1. A board having a structure in which a fibrous reinforcing material made of single fibers (filaments) is covered with a polybutylene terephthalate resin, and the polybutylene terephthalate resin is impregnated into the fibrous reinforcing material. In the molding material obtained by obtaining a shaped body and cutting the plate-shaped body filled with the fibrous reinforcing material, (i) the filling rate of the fibrous reinforcing material with respect to the molding material is 50% by weight or more and 90% by weight; % or less, (ii) the length of the fibrous reinforcing material is 1 to 30 mm, (ii
i) at least one side of the plate-like body is 1 mm or less; (iv)
The specific surface area of the molding material is 20 cm^2/g or more (v) The melt fluorate of the polybutylene terephthalate resin is 10 g/10 minutes or more when measured at a test temperature of 235°C and a test load of 2.16 kgf based on JIS K7210. A molding material characterized in that it is 100g/10 minutes or less. 2. Comprising the molding material according to claim 1 and a fiber-unreinforced resin, the melt fluor rate of the fiber-unreinforced resin is 0.05 to 1 times the melt fluor rate of the resin (measured under the same conditions).
A molding material mixture characterized in that it is