JPH07232324A - Melt molding mixture of long-glass-fiber reinforced polypropylene with polypropylene, and molded item thereof - Google Patents

Abstract

PURPOSE:To obtain a long-glass-fiber reinforced polypropylene resin molded article superior in mechanical strength and a melt molding mixture for producing it. CONSTITUTION:While a roving of reinforcing continuous glass fibers surface treated with a surface treating agent containing a coupling agent is drawn, the glass fiber roving is impregnated with a modified polypropylene resin having functional groups capable of chemically bonding with the coupling agent and a melt flow rate (ASTMD-1238, load: 2.16kg, temperature: 230 deg.C) of 70-300g/10min. After that, the roving is cut, whereby a pellet of 2-50mm in a fiber direction is obtained. The glass fibers having substantially the same length as the pellet are oriented in parallel. The long-glass-fiber reinforced polypropylene resin containing 60-90wt.% glass fiber is used as a master batch. A melt molding mixture of a long-glass-fiber reinforced polypropylene and a polypropylene consists of 5-70wt.% master batch and 30-95wt.%, polypropylene resin. A resin molded article is produced using this mixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixture for a melt molding material for obtaining a long glass fiber reinforced polypropylene resin molded product having excellent mechanical strength and the molded product thereof.

[0002]

2. Description of the Related Art Glass fiber reinforced polypropylene resin is
Due to its excellent mechanical strength, heat resistance and moldability, it is widely used in various industrial parts. In particular, a long fiber reinforced polypropylene resin obtained by a so-called drawing method in which a resin is impregnated while drawing continuous fibers is a short fiber reinforced polypropylene resin obtained by kneading a chopped strand of glass fiber and a resin in an extruder or a molding machine. It has the advantages of superior impact strength, creep characteristics and vibration fatigue characteristics. Further, the long fiber reinforced polypropylene resin produced by the drawing method has a feature that the glass fibers can be filled with extremely high density because the glass fibers are arranged in the same direction.

For example, a short fiber reinforced polypropylene resin produced by kneading with an extruder has a glass fiber content of 50.
Whereas if it exceeds the weight%, it becomes difficult to manufacture, whereas the long glass fiber reinforced polypropylene resin manufactured by the drawing method is
Even if the glass fiber content is 80% by weight, it can be easily manufactured. Taking advantage of this advantage, the long fiber reinforced polypropylene resin having a high glass fiber content produced by the drawing method is often used as a masterbatch.

This is because when a long fiber reinforced polypropylene resin having a high glass fiber content is used as a masterbatch, the degree of freedom of the mixing ratio of the polypropylene resin for dilution mixed with the masterbatch is increased, so that various fibers suitable for the purpose of use are contained. This is because a melt-molded product of a long glass fiber reinforced polypropylene resin having a high ratio can be obtained, which is advantageous from the economical point of view and the wide range of product application.

However, it is difficult for the long glass fiber reinforced polypropylene produced by the drawing method used for the conventional masterbatch to completely impregnate the polypropylene resin while drawing glass fibers composed of thousands to tens of thousands of filaments. In addition, the hydrophilic glass fiber and the non-polar polypropylene resin have the drawback of poor wettability. The following methods have been disclosed as methods for improving these drawbacks.

[0006] For example, in Japanese Patent Laid-Open No. 5-17631, in order to facilitate impregnation of molten resin, ASTM D-1
A method using low viscosity polypropylene having a melt flow rate of 30 g / 10 min or more measured by a method of 238 (load: 2.16 kg, temperature: 230 ° C.), Japanese Patent Publication No. 3-25340 is impregnated with an extremely low molecular weight resin. In order to improve the wettability, there is a method of surface-treating glass fiber and using a modified polypropylene resin, as disclosed in Japanese Patent Laid-Open No. 3-181528.

On the other hand, the following methods have been disclosed in order to obtain molded articles by the masterbatch method. JP-A 1-2
No. 41406 discloses a method of molding a dry blend of a long fiber reinforced thermoplastic resin and a thermoplastic resin not containing long fibers, and Japanese Patent Laid-Open No. 3-114705 discloses a polypropylene resin having a melt flow rate of 20 to 60 g / 10 minutes. Using a small pellet having a specific surface area of at least one side of 1 mm or less and a specific surface area of 20 cm ² / g or more, and JP-A-59-20339 discloses a mixed fiber of glass fiber and modified polypropylene fiber. A method of heating is disclosed.

[0008]

However, when a conventional long glass fiber reinforced polypropylene resin is used as a masterbatch, the higher the glass fiber content is, the stronger the strength of the molded product obtained by diluting and molding the glass fiber with the polypropylene resin is. Compared to the undiluted long glass fiber reinforced polypropylene resin with the same glass content, it tends to decrease. This tendency becomes remarkable especially when the glass fiber content exceeds 60% by weight. The above-mentioned prior art discusses resin impregnation techniques, in particular, high content of fibers, improvement of wettability, or various methods of obtaining molded articles from a masterbatch.

However, there is no disclosure of such drawbacks when using long glass fiber reinforced polypropylene resin as a masterbatch, and no suggestion of how to overcome it. If the drawback of reduced strength of molded products using a masterbatch with a high glass fiber content is solved, one type of long glass fiber reinforced polypropylene resin masterbatch will be used to reinforce various types of long glass fiber reinforced depending on the purpose of use. Industrial value is extremely high because polypropylene resin molded products can be obtained at low cost.

The present invention provides a melt-molding mixture and a molded product thereof, which is composed of a long glass fiber polypropylene resin masterbatch and a polypropylene resin mixture capable of obtaining a high-strength molded product, which solves the above problems. With the goal.

[0011]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventor has made a melt composed of a long fiber reinforced polypropylene resin masterbatch having a high glass fiber content and a polypropylene resin in order to obtain a high strength molded product. As a result of diligent studies on the mixture for molding material and its molded product, it was found that the following is important for solving the problem.

First, the glass fibers in the masterbatch produced by the drawing method are well dispersed. Second, the interface between the glass fiber and the polypropylene resin in the masterbatch should be in close contact. Thirdly, it is necessary to keep the viscosity of the matrix resin in the masterbatch within a specific range in order to reduce the apparent viscosity of the entire masterbatch and maintain the strength. Based on the above findings, melt-molded products obtained from a mixture of long glass fiber reinforced polypropylene resin masterbatch and polypropylene resin for the first time when glass fiber and resin are subjected to specific conditions, have good dispersion of glass fibers and It was found that a product having excellent surface appearance and high strength can be obtained.

Here, the technical ideas so far in the field of the present invention will be collectively described. In order to obtain high mechanical strength, long glass fiber reinforced polypropylene, even if the method of surface treatment of the above-mentioned glass fiber or chemical modification by polypropylene modification is performed to improve wettability and adhesion, the matrix It can be easily understood that the polypropylene used in the above is preferably one having a high molecular weight and high strength, in other words, one having a small melt flow rate.

On the other hand, in order to uniformly disperse the long glass fiber as a reinforcing material in the matrix, it is necessary to impregnate polypropylene into a glass fiber bundle consisting of thousands to tens of thousands of filaments. It has high liquidity, that is,
Polypropylene having a high melt flow rate is advantageous because it has higher permeability. Thus, it can be said that polypropylene for matrix use has antinomy.

In Japanese Patent Laid-Open No. 3-114705, the melt flow rate is 60 g / 10 minutes (20 to 60 g / 10 minutes), which is very high as compared with the conventional product by using polypropylene as a matrix, which has a high melt flow rate. A plate-shaped masterbatch has been proposed in order to achieve the glass fiber content and increase the thermal conductivity. However, in the present technical field, it was common sense that when using such a matrix polypropylene for a masterbatch, giving more fluidity would be negative from the viewpoint of resin strength.

The present inventors, which will be described later in Comparative Example 4,
Using polypropylene with a melt flow rate of 60 g / 10 min as a matrix, a pellet-shaped masterbatch with a high fiber content was prepared, mixed with a polypropylene resin for dilution, and then melt-molded. It was confirmed that the glass fiber had an extremely high viscosity and the glass fiber was not easily dispersed throughout the resin.

However, the inventors of the present invention, in the process of studying the invention, have a melt flow rate of 70 to 300 g / 10 min.
A masterbatch having a high content of long glass fibers was prepared by using polypropylene, which has extremely low resin strength and has extremely high fluidity as compared with the conventional one, as a matrix. This masterbatch itself had low strength, but surprisingly, when it was mixed with polypropylene for dilution to obtain a melt-molded product, the melt-molded product of the present invention had a smaller melt flow rate and a higher strength. As a result, they have found that the strength is higher than that of a conventional melt-molded product using an advantageous polypropylene masterbatch, and have completed the present invention.

That is, the present invention has a functional group capable of chemically bonding with the coupling agent while drawing out the reinforcing continuous glass fiber bundle surface-treated with the surface treatment agent containing the coupling agent, Melt flow rate (A
STM D-1238, load: 2.16kg, temperature: 230 ℃) 70g
A pellet having a length of 2 to 50 mm in the fiber direction obtained by impregnating the glass fiber bundle with a modified polypropylene resin that is / 10 minutes or more and 300 g / 10 minutes or less, and the glass fiber is substantially pelletized. A machine made of a long glass fiber reinforced polypropylene resin having a glass fiber content of 60 to 90% by weight as a master batch, the master batch being 5 to 70% by weight, and the polypropylene resin being 30 to 95% by weight. The present invention provides a long glass fiber reinforced polypropylene excellent in dynamic strength, a mixture of polypropylene for melt molding, and a molded product thereof. Other features of the invention, as well as various aspects thereof, will be apparent in the following detailed description.

[0019]

The present invention will be described in more detail below. The continuous glass fibers used in the present invention are E-glass, S-glass, C-glass, AR-glass, T-glass, D-glass and R-glass, etc., and usually a plurality of glass filaments are collected. It is in the form of so-called glass roving, which is a coil of a bundle. A glass fiber having a diameter of 3 to 40 μm is suitable. If it is less than 3 μm, it becomes difficult to impregnate the resin with the same glass content because the number of glass fibers is relatively increased, and if it exceeds 40 μm, the surface appearance of the molded product is remarkably deteriorated. The optimum glass fiber diameter is 9 to 20 μm.

The glass fiber used in the present invention must be surface-treated with a surface-treating agent containing a coupling agent. Since the glass fiber not surface-treated is hydrophilic, it has poor wettability with the lipophilic polypropylene resin, and a large surface tension occurs between the two, making it difficult for the polypropylene resin to be impregnated between the glass fibers not surface-treated. As a result,
In the molded product, there is a mass of resin and glass fiber that is not wet, which causes poor appearance and lower strength.

As the coupling agent, aminosilane,
Silane coupling agents such as epoxy silanes, amido silanes, azido silanes, acrylic silanes, titanate based coupling agents and mixtures thereof can be utilized. Of these, aminosilane and epoxysilane are the best,
Particularly, the aminosilane coupling agent is most suitable.

The surface treatment agent may contain components other than the coupling agent, and is modified with a urethane resin, an epoxy resin, a vinyl acetate resin, (meth) acrylic acid or an acid anhydride as a sizing agent. Modified or non-modified polyolefins such as polyethylene, polypropylene are suitable. As the lubricant, cation-based, nonion-based, anion-based, and silicon-based compounds correspond to this. The surface treatment agent is 0.05 to 3% by weight in glass fiber.
Desirable to be present. If it is less than 0.05% by weight, the effect of the surface treatment is not sufficiently exerted, and if it exceeds 3% by weight, the molded product is colored and deteriorated by heat, which is not preferable.

The modified polypropylene resin having a functional group capable of chemically bonding with the coupling agent used in the present invention is preferably a carboxylic acid modified polypropylene resin, an acid anhydride modified polypropylene resin or an epoxy modified polypropylene resin. . These modified polypropylene resins include monomers such as (meth) acrylic acid, maleic acid, itaconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, and (meth) acrylic acid glycidyl ester in the presence of a radical initiator. It can be obtained by melt-kneading with a polypropylene resin in an extruder.

The functional group capable of binding to the coupling agent is preferably present in the modified polypropylene resin in an amount of 0.01 to 5% by weight in terms of the modifying monomer. 0.0
If it is less than 1% by weight, a sufficient amount of polymer is not grafted on the glass surface, so that the molded product has low strength. On the other hand, if it exceeds 5% by weight, the molded product is colored, the heat resistance is lowered, and the strength is lowered, such being undesirable. The most suitable modified polypropylene resin is a maleic anhydride modified polypropylene resin grafted with 0.02-1.5 wt% maleic anhydride.

The modified polypropylene resin used for impregnating the glass fibers can be used as a modified polypropylene resin alone, or as a mixture of modified polypropylene resin and polypropylene resin. The latter case is also expressed as a modified polypropylene resin and included in the scope of the present invention, and the proportion of the polypropylene resin is not particularly limited. However, in all cases, the overall melt flow rate is 70-3.
Must be in 00g / 10 minutes.

As described above, the modified polypropylene resin is a polypropylene resin grafted with a modifying monomer, and the polypropylene resin here is a polymer unit of propylene, which is a constituent unit of the backbone polymer of the modified polypropylene resin. What contains 70% by weight or more,
Examples include propylene homopolymers and copolymers of less than 30% by weight of vinyl group-containing monomers copolymerizable with propylene and 70% by weight or more of propylene. Examples of copolymers include propylene-ethylene random and block copolymers, propylene-butene copolymers, and propylene-EPDM copolymers. The modified polypropylene resin may be used alone or in combination of two or more kinds. The most preferred modified polypropylene resin is 0.02-1.
5% by weight of a maleic anhydride-modified propylene homopolymer and 0.02-1.5% by weight of a maleic anhydride-modified ethylene content of 5% by weight or less ethylene-propylene copolymer.

In the present invention, the glass fiber is surface-treated with a surface-treating agent containing a coupling agent, and the modified polypropylene resin is used as the impregnating resin. The interfacial strength between polypropylene and the polypropylene matrix resin is increased, and the strength of the molded product is significantly increased.

The modified polypropylene resin used as the matrix resin of the masterbatch used in the present invention is ASTM
D-1238 (load 2.16 kg, temperature 230 ° C) (melt flow rates shown below are all measured by this method) If the melt flow rate is 70 g / 10 min or more and 300 g / 10 min or less I won't. 70 g /
When it is less than 10 minutes, the glass fiber is not uniformly dispersed when the mixture of the masterbatch and the polypropylene resin is melt-molded, and the obtained molded product has a light and shade of a portion having a high density of glass fiber and a portion having a small glass fiber density. In addition, the strength of the molded product becomes low. When it exceeds 300 g / 10 minutes, the dispersion of the glass fiber in the molded product is good, but the strength of the molded product is lowered because the matrix resin has a low molecular weight. The optimum melt flow rate of modified polypropylene resin is 8
It is 0 to 150 g / 10 minutes.

The masterbatch pellets of the long glass fiber reinforced polypropylene resin of the present invention are obtained by impregnating the glass fiber with the modified polypropylene resin while drawing the above-mentioned continuous glass fiber for strengthening, and then in the direction perpendicular to the direction of drawing the fiber. It is obtained by cutting into. Any method may be used for impregnating the resin. For example, a method in which glass fiber is impregnated with an emulsion of a modified polypropylene resin and coated and then dried, a method in which a powder suspension of a modified polypropylene resin is adhered to the glass fiber, dried and then heat-melted and impregnated, and the glass fiber is charged. , A method of impregnating the modified polypropylene resin powder by heating and melting, impregnating the glass fiber with the modified polypropylene resin dissolved in a solvent, and then removing the solvent, a mixed fiber of continuous fiber of modified polypropylene and continuous fiber of glass May be used to impregnate the molten modified polypropylene into the molten polypropylene, or to heat and melt the modified polypropylene resin to impregnate the glass fiber while opening the glass fiber on a bar, a roll, or a die. Among these methods, the method of impregnating the modified polypropylene resin heated and melted while opening the glass fiber on a bar, a roll, or a die is most preferable because of the simplicity of the apparatus and the process.

In the pellets for master batch after cutting thus obtained, the glass fibers are present in a state of being aligned in parallel with each other in the same length as the pellets. The pellets contain 60 to 90% by weight of glass fibers, and the pellet length is 2 to 50 mm in the fiber direction. If the glass fiber content is less than 60% by weight, the advantages of the masterbatch described above cannot be utilized, which is economically disadvantageous, and the product range of the molded product after dilution is narrowed, which has an industrial value. Decrease. If it exceeds 90% by weight, the resin cannot be sufficiently impregnated and the production becomes extremely difficult. The preferred glass fiber content is 70 to 85% by weight. If the pellet length is less than 2 mm, the glass fiber length in the molded product becomes short and the strength, particularly the impact strength, decreases. If it exceeds 50 mm, high strength, high impact, creep resistance and vibration fatigue resistance, which are the features of long fiber reinforcement, will not be further improved.
On the contrary, it is not preferable because segregation occurs in the hopper at the time of injection molding or extrusion molding, or segregation occurs in a mixture with the polypropylene resin. Preferable pellet length is 3-25mm
Is. The pellet shape may be any shape as long as the length is 2 to 50 mm, and for example, the cut surface may be circular, oval, or quadrangular. The length of the cut surface in the longitudinal direction is preferably such that the aspect ratio (ratio between the pellet length and the cut surface length) is 1 to 10, more preferably 2 to 5.

The polypropylene resin for dilution used in the present invention, which is mixed with the masterbatch pellets of long glass fiber reinforced polypropylene resin, contains 70% by weight or more of propylene as a constituent unit. For example, propylene homopolymer and propylene are used. There are copolymers composed of less than 30% by weight of copolymerizable vinyl group-containing monomers and 70% by weight or more of propylene, and mixtures thereof. Examples of copolymers include ethylene-propylene random copolymers, ethylene-propylene block copolymers, propylene-butene copolymers, and propylene-EPDM copolymers. There is no particular limitation on the melt flow rate of the polypropylene resin for diluting the masterbatch. However, if it is less than 1 g / 10 minutes, there is a drawback that the fluidity is lowered and the moldability is deteriorated, and if it exceeds 200 g / 10 minutes, the strength of the diluted molded article, especially the impact strength is lowered. . A preferred range is 5 g / 10 minutes to 150 g / 10 minutes.

These polypropylene resins for dilution can be used properly according to the purpose of use of the molded product. For thin molded products, the melt flow rate is 30 g / 10 min-10
A material having a good fluidity of 0 g / 10 minutes is suitable. When impact resistance is required, the melt flow rate is 3 to 2
At 0 g / 10 minutes, the ethylene component is 10 to 30% by weight, the ethylene-propylene block copolymer or the melt flow rate is 3 to 20 g / 10 minutes, and the EPDM content is 1
Preference is given to using 0 to 30% by weight of propylene-EPDM copolymer.

Particularly when impact resistance is required, ethylene-propylene copolymer and propylene-EPDM copolymer have high melt viscosity and are difficult to impregnate into glass fiber. It is difficult to manufacture reinforced melt-molded products. Thus, melt molding using a mixture of a masterbatch having a modified polypropylene resin of a specific low viscosity range of the present invention and a polypropylene resin for these high impact copolymers produces long glass fiber reinforced molded articles of these resins. Is an effective means for

The mixing ratio of the long glass fiber reinforced polypropylene resin masterbatch of the present invention and the polypropylene resin for dilution is as follows: masterbatch / polypropylene resin = 5 /
It is 95-70 / 30 (weight ratio). If the mixing ratio of the masterbatch is less than 5% by weight, the glass fiber content in the molded product after dilution is too low,
High strength and high impact cannot be fully exhibited. Also,
When it exceeds 70% by weight, the amount of the polypropylene resin for dilution used is less than 30% by weight, which is economically disadvantageous.
It has the disadvantage of narrowing the product application range of molded products, reducing the industrial value. The optimum masterbatch / polypropylene resin mixing ratio is 20/80 to 50/50 (weight ratio).

The shape of the polypropylene resin for dilution is not particularly limited, but powder and pellets are preferable. It is more preferable that the size and shape of the masterbatch pellet be close to each other. If the sizes of both pellets are extremely different, there is a drawback that they separate in the hopper during melt molding. The preferred polypropylene resin shape is 2-5 mm
Or a cylindrical shape having a diameter of 1 to 5 mm and a length of 1 to 10 mm.

The melt-molding mixture of the present invention further contains an antioxidant such as a phenol-based or phosphorus-based antioxidant, an ultraviolet absorber,
Dyes / pigments for coloring, higher fatty acids, higher fatty acid metal salts, amides of higher fatty acids, lubricants such as waxes and the like can be added.

The melt molding of the mixture of the present invention can be carried out using a conventional injection molding machine, injection-press molding machine, single-screw extruder, twin-screw extruder, or heat press molding machine. The molded product is an ordinary injection-molded product, a bar-shaped or plate-shaped modified extrusion-molded product obtained by profile extrusion, or a sheet.

The average fiber length (median length) of the residual fiber length in the molded product obtained by melt-molding the mixture of the above masterbatch and polypropylene resin must be 0.8 to 10 mm. If it is less than 0.8 mm, the high strength, high elastic modulus, excellent creep characteristics and vibration fatigue characteristics, which are features of the long fiber reinforced molded product, cannot be sufficiently exhibited. Further, if it exceeds 10 mm, the characteristics of the long fiber reinforced molded product are not further improved, and the surface appearance is rather deteriorated, which is not preferable.

In order to maintain the residual average glass fiber length of 0.8 to 10 mm, the melt molding mixture of the present invention has a relatively mild melt molding condition, that is, the kneading force is weakened and the shearing force applied to the molten resin is reduced. There is a need to. For example, using a deep groove screw, the back pressure of the screw is 0 to 3 kg /
It is necessary to take measures such as making it as small as cm ² or reducing the screw rotation speed. In the melt-molding mixture of the present invention, the glass fibers are sufficiently dispersed even when the kneading force is weak as described above.

The high-strength melt-molded product can be obtained by the present invention as follows. One reason is that the content of long glass fibers in the masterbatch is increased, the surface treatment of the glass fiber is performed, and the adhesion between the two is increased by modifying the polypropylene resin for masterbatch. Furthermore, the modified polypropylene having high fluidity, which is strongly bonded on the surface so as to coat the glass fiber, is easily compatible with the diluting polypropylene, and the apparent viscosity during melt molding is lowered, so that it is easily dispersed in the diluting polypropylene resin. It seems to be. Therefore, even if polypropylene for master batch has a high melt flow rate,
It is considered that if the melt flow rate of the polypropylene for dilution is lowered, a molded product having higher strength can be obtained.

[0041]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. Examples 1 to 5 Polypropylene homopolymer having a melt flow rate of 8 g / 10 min: 100 parts by weight, maleic anhydride: 2 parts by weight and 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne. -3: 0.3 part by weight of the mixture was melt-kneaded and extruded at 180 ° C. using a vented twin-screw extruder to obtain a melt flow rate of 1
A maleic anhydride-modified polypropylene resin having a grafted maleic anhydride content of 1.2% by weight at 20 g / 10 minutes was obtained.

The above modified polypropylene resin 20 obtained
% By weight and 60 g / 10 melt flow rate each
Min (Example 1), 80 g / 10 min (Example 2), 120
g / 10 min (Example 3), 200 g / 10 min (Example 4), 300 g / 10 min (Example 5) a mixture of 80% by weight of polypropylene homopolymer was mixed with a twin-screw extruder.
The mixture was melted and kneaded at 20 ° C., and five molten metal rolls were placed inside and the molten resin was poured into an impregnation bath maintained at a temperature of 280 ° C. Surface-treated with 0.2% by weight of γ-aminopropyltriethoxysilane as a surface treatment agent,
Five glass rovings (about 11600 glass filaments in total) in which about 2,320 glass filaments with a diameter of 16 μm were converged were alternately passed over the five rolls in the molten resin in the impregnation bath, and a tension of about 2 kg was applied to the roving. While opening the glass filament on the roll by applying the roving, the roving was pulled out at a speed of 1 m / min (residence time: 30 seconds) to impregnate the glass fiber with the resin. The glass fiber impregnated with the resin was passed through a die having a diameter of 2.5 mm, cooled, and cut into a length of 10 mm with a cutter. Ash the obtained pellets in a muffle furnace at 450 ° C for 8 hours,
When the glass content rate was measured, the glass content rate was 75% by weight. Further, after ashing the pellets, glass fibers having the same length as the pellets were arranged in parallel. When a part of the modified polypropylene molten resin in the impregnation bath was taken out and the melt flow rate was measured, it was 82 g /
10 minutes, 95g / 10 minutes, 125g / 10 minutes, 190g
/ 10 minutes, 280 g / 10 minutes.

53.3% by weight of the obtained masterbatch pellets containing 75% by weight of glass fiber and 46.7% by weight of polypropylene resin (homopolymer) pellets (granular particles having a diameter of 3 mm) having a melt flow rate of 45 g / 10 min. After mixing, the mixture was injection-molded by an injection molding machine with a mold clamping force of 50 t under the conditions of an injection molding temperature of 240 ° C. and a mold temperature of 60 ° C. The tensile strength (ASTM D-638) and Izod impact strength (ASTM D-256, with notch) of the obtained molded product were measured.
The results are shown in Table 1.

(Comparative Examples 1 to 6) As impregnating resins, polypropylene resins mixed and kneaded with a maleic anhydride-modified polypropylene resin have a melt flow rate of 3.5 g / 10 min (Comparative Example 1) and 12 g / 10, respectively. Minute (Comparative Example 2), 30 g / 10 minutes (Comparative Example 3), 45 g / 10 minutes (Comparative Example 4), 400 g / 10 minutes (Comparative Example 5) The operation was performed. The same operation as in Example 3 was performed except that the glass fiber which was not surface-treated was used (Comparative Example 6). The results are shown in Table 1.

In Comparative Examples 1 to 5, since the melt flow rate of the modified polypropylene resin which is the matrix resin of the masterbatch is out of 70 to 300 g / 10 minutes, the glass fibers are not uniformly dispersed and the tensile strength (kg
/ Cm ^2), none of the Izod (I _Zod) impact strength (kg · cm / cm) has decreased by a large margin as compared with Example 1-5.

Further, in Comparative Example 6, the glass fiber is not surface-treated, so that the wettability with the polypropylene resin is poor.
For this reason, the polypropylene resin is less likely to be impregnated between the glass fibers, and the tensile strength and Izod impact strength are also reduced.

(Examples 6 to 10 and Comparative Example 7) When a long glass fiber reinforced polypropylene resin masterbatch was produced, the composition of the molten resin for impregnation was changed to maleic anhydride modified polypropylene resin / polypropylene resin = 0/100 (comparison). Example 7), 2/98 (Example 6), 5/95 (Example 7), 10/90 (Example 8), 50/50 (Example 9), 0/100 (Example 10) (any) The same experiment as in Example 3 was performed except that the weight ratio was also set. The results are shown in Table 2.
Shown in. The melt flow rate of the matrix resin of the masterbatch is 122 g / 10 minutes (Comparative Example 7), 122 g / 10 minutes (Example 6), and 123 g / 10, respectively.
Min (Example 7), 123 g / 10 min (Example 8), 12
4 g / 10 minutes (Example 9), 125 g / 10 minutes (Example)
It was 10).

Since Comparative Example 7 uses polypropylene containing no maleic anhydride, it cannot chemically bond with the coupling agent on the surface of the glass fiber, resulting in low tensile strength and impact strength.

(Comparative Examples 8-9, Examples 11-14) In Comparative Example 8, the glass roving used in Example 3 had a length of 3
40% by weight of chopped strands cut into mm, 12% by weight of the modified polypropylene resin used in Example 3 and 48% by weight of a polypropylene resin having a melt flow rate of 120 g / 10 min used in Example 3 were mixed, and this was biaxially mixed. Using an extruder, the mixture was kneaded and extruded at a temperature of 270 ° C. to obtain a cylindrical pellet having a length of 10 mm and a diameter of 3 mm. The pellets were injection-molded and the physical properties were measured in the same manner as in Example 3. Further, the injection molded product was ashed in a muffle furnace, and the average length of the glass fiber was determined. Further, the pellet length of the long glass fiber reinforced polypropylene resin was 1 mm (Comparative Example 9),
2 mm (Example 11), 5 mm (Example 12), 30 m
m (Example 13) and 50 mm (Example 14), except that the same operation as in Example 3 was performed. Moreover, the average length of the glass fiber in the injection-molded article was measured. The results are shown in Table 3.
Shown in. In Comparative Example 8, the glass fiber breaks during kneading and the fiber length becomes short, so the strength becomes low. Further, in Comparative Example 9, since the pellet length is 1 mm, which is shorter than the 2 mm of the present invention,
The tensile strength and especially the impact strength are reduced.

(Examples 15 to 17, Comparative Examples 10 to 12)
Injection molding and physical properties were performed in the same manner as in Example 3 except that the mixing ratio of the long glass fiber reinforced polypropylene resin used in Example 3 and the propylene-EPDM copolymer containing 30% by weight of EPDM (melt flow rate 10 g / 10 min) was changed. An evaluation was performed. The results are shown in Table 4.

Comparative Example 10 has a small glass fiber content,
The tensile strength is low because the effect of reinforcing long fibers is not exhibited. On the contrary, in Comparative Examples 11 and 12, the mixing ratio of the masterbatch is too large and the tensile strength and the impact strength are lowered.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

EFFECTS OF THE INVENTION Heretofore, molded articles obtained by melt-molding a mixture of a long glass fiber reinforced polypropylene resin having a high glass fiber content and a polypropylene resin have not been able to uniformly disperse glass fibers and have insufficient strength. . A mixture of long glass fiber reinforced polypropylene resin masterbatch and polypropylene resin of the present invention is a glass fiber treated with a coupling agent, and by using a very low viscosity modified polypropylene resin as a matrix resin in the masterbatch,
Even though the masterbatch has a high glass fiber content, the glass fibers are uniformly and well dispersed, and a high-strength molded product having an excellent surface appearance can be provided. Therefore, only by preparing one type of glass long fiber reinforced polypropylene resin masterbatch with a high glass fiber content of the present invention, by changing the type of polypropylene resin for dilution or changing the mixing ratio, depending on the purpose of use. Also, various long glass fiber reinforced molded products can be easily and inexpensively produced.

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Claims (8)

[Claims] 1. A mixture for melt molding obtained by using a continuous glass fiber reinforced polypropylene resin obtained by impregnating a continuous glass fiber bundle with a resin as a masterbatch, and adding the resin to the masterbatch. While pulling out the reinforcing continuous glass fiber bundle surface-treated with a surface treatment agent containing a ring agent, it has a functional group that can be chemically bonded to the coupling agent, melt flow rate (ASTM D-1238, load : 2.16k
g, temperature: 230 ° C) is 70 g / 10 minutes or more and 300 g / 1
A length of 2 to 50 in the fiber direction obtained by impregnating the glass fiber bundle with a modified polypropylene resin for 0 minutes or less and cutting the glass fiber bundle.
mm pellets, the glass fibers being substantially the same length and aligned in parallel with the pellets and having a glass fiber content of 6
0 to 90 wt% long glass fiber reinforced polypropylene resin is used as a masterbatch, and the masterbatch is 5 to 70 w
A melt-molding mixture of long glass fiber reinforced polypropylene consisting of t% and polypropylene resin of 30 to 95 wt% and polypropylene. 2. The modified polypropylene resin having a functional group capable of chemically bonding to the coupling agent is one or two kinds selected from carboxylic acid modified polypropylene resin, acid anhydride modified polypropylene resin and epoxy modified polypropylene resin. The melt molding mixture of the long glass fiber reinforced polypropylene according to claim 1 and polypropylene as described above. 3. The constitutional unit of the trunk polymer of the modified polypropylene resin is selected from a propylene homopolymer and a copolymer of less than 30 wt% of a vinyl group-containing monomer copolymerizable with propylene and 70 wt% or more of propylene.
The melt-molding mixture of the long glass fiber reinforced polypropylene according to claim 1 or 2, which is one kind or two or more kinds. 4. The coupling agent is an aminosilane coupling agent, and the modified polypropylene resin is 0.1.
A maleic anhydride-modified polypropylene homopolymer of 02 to 1.5 wt% or an ethylene-propylene copolymer having an ethylene content of 5 wt% or less modified with 0.02 to 1.5 wt% of maleic anhydride. A melt-molding mixture of the long glass fiber reinforced polypropylene described in the above and polypropylene. 5. The polypropylene resin mixed with the long glass fiber reinforced polypropylene resin masterbatch is AS
The melt flow rate measured by the method of TM D-1238 (ASTM D-1238, load: 2.16 kg, temperature: 230 ° C.) is 5
It is g / 10 minutes or more and 150 g / 10 minutes or less.
Mixture of long glass fiber reinforced polypropylene and polypropylene for melt molding according to item 6. The polypropylene resin mixed with the long glass fiber reinforced polypropylene resin masterbatch comprises polypropylene homopolymer or less than 30 wt% vinyl group-containing monomer copolymerizable with propylene and propylene 7.
The melt molding mixture of the long glass fiber reinforced polypropylene and polypropylene according to any one of claims 1 to 5, which is one kind or two or more kinds selected from 0 wt% or more of a copolymer. 7. A copolymer of a vinyl group-containing monomer copolymerizable with propylene and propylene is an ethylene-propylene block copolymer having an ethylene content of 10 to 30 wt%, and an EPDM containing EPDM of 10 to 30 wt%. The melt molding mixture of long glass fiber reinforced polypropylene and polypropylene according to claim 6, which is a propylene copolymer or a mixture thereof. 8. A melt flow rate (having a functional group capable of chemically bonding with the coupling agent while pulling out a reinforcing continuous glass fiber bundle surface-treated with a surface treatment agent containing a coupling agent, ASTM D-1238, load: 2.16 kg, temperature: 230 ° C) is 70 g / 10 min or more 3
Modified polypropylene resin that is less than or equal to 00 g / 10 minutes,
A pellet having a length of 2 to 50 mm in the fiber direction obtained by impregnating the glass fiber bundle and cutting the glass fiber bundle, wherein the glass fibers are substantially aligned in parallel with the pellet and have a glass fiber content of 60. ~ 90wt% long glass fiber reinforced polypropylene resin as a masterbatch, the masterbatch is 5 ~ 70wt%, polypropylene resin 30 ~ 95wt
% Long glass fiber reinforced polypropylene and a long glass fiber reinforced polypropylene excellent in mechanical strength containing a glass fiber having a residual average length of 0.8 to 10 mm, which is obtained by melt molding a mixture for long-fiber reinforced polypropylene and polypropylene. Molded product.