JP2001192468A - Long fiber-reinforced polyolefin resin composition and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long fiber-reinforced polyolefin resin composition which has excellent weather resistance and can give a molded article having excellent durability such as excellent mechanical strengths and excellent fatigue characteristics, especially excellent flexural fatigue characteristics, because the fibers can be held in long sizes in the molded article, and to provide the molded article obtained from the resin composition. SOLUTION: This long fiber-reinforced polyolefin resin composition characterized by comprising (A) a polyolefin resin in an amount of 28 to 94.98 wt.% based on the composition, (B) reinforcing fibers having a length of 2 to 50 mm and impregnated with the polyolefin resin in an amount of 5 to 60 wt.%, (C) zinc sulfide in an amount of 0.01 to 10 wt.%, and (D) a hindered amine photostabilizer having a mol.wt. of >=1,000 in an amount of 0.01 to 2 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a long-fiber-reinforced polyolefin resin composition suitably used for automotive exterior applications and the like, and a molded article obtained therefrom. More specifically, since the reinforcing fibers used in the molded article are retained for a long time even when molded, the molded article has excellent durability such as mechanical strength and fatigue properties, particularly bending fatigue properties. The present invention relates to a long fiber reinforced polyolefin resin composition from which a product is obtained, and a colored molded product obtained therefrom.

[0002]

2. Description of the Related Art A so-called long-fiber reinforced polyolefin resin obtained by impregnating a continuous fiber bundle for reinforcement with a molten polyolefin resin, drawing it out, and pelletizing it to a length of 2 to 50 mm is known as mechanical strength or heat resistance. Because of its excellent properties, it is widely used for automotive parts and industrial parts.

Needless to say, coloring is required depending on the use of a molded article obtained from a long-fiber reinforced polyolefin resin, and in most cases other than black colored articles, a colored pigment mixed with a white pigment is used in order to develop color. Pigments are used. The most commonly used white pigment is titanium oxide. However, when a long-fiber reinforced polyolefin resin using glass fiber as a continuous fiber for reinforcement is colored with a coloring pigment containing titanium oxide, the hardness of titanium oxide is higher than that of glass. Thus, there is a problem in that the resulting colored molded product is greatly reduced in mechanical strength, particularly in impact resistance. For this reason, zinc sulfide, which has a lower hardness than glass, has recently been reviewed as a white pigment, particularly in the field of long fiber reinforced resins.

[0004] Japanese Patent No. 2813559 proposes a glass fiber reinforced polypropylene resin molded product containing zinc sulfide as a white pigment. According to this method, it is possible to prevent the glass fiber from being damaged and to suppress a decrease in the mechanical strength of the molded article. However, it has been found that an unacceptable problem occurs when a light stabilizer is added to the glass fiber reinforced polypropylene resin molded article and used for an application exposed to sunlight. That is, the weather resistance is significantly inferior to the case where titanium oxide is used as the white pigment. Specifically, in the case of a glass fiber reinforced resin, a so-called thin resin occurs, and a phenomenon occurs in which the glass fibers emerge. Further, when exposed to rain outdoors, zinc sulfate, which is an oxidation product of zinc sulfide, is washed away by the rain, and a phenomenon in which the color of the molded product becomes dark, that is, darkening also occurs. As a way to improve the above problem,
Similarly, Japanese Patent No. 2813559 proposes to further contain a cobalt salt. Although the effect of improving the weathering performance by the combined use of the cobalt salt is certainly recognized, it is still insufficient, and as a result of additional tests, it has been found that there is no effect of improving the darkening.

Japanese Patent Application Laid-Open No. Hei 9-183869 discloses a method for improving weather resistance by adding a combination of a light stabilizer and a light absorber to a zinc sulfide-containing glass long fiber reinforced polyolefin composition. Proposed. Although the effect of improving the weather resistance due to the combined use of the light stabilizer and the light absorber is recognized, the weather resistance is still insufficient, as a result of additional tests, the light stabilizer and the light absorber must be contained in large amounts. As in the above-mentioned Patent No. 2813559,
It was found that there was no improvement effect on darkening.

[0006]

As described above, even in applications where a molded article needs to be colored, it has excellent weather resistance,
Especially improved darkening, mechanical strength and fatigue properties,
In particular, a long-fiber-reinforced polyolefin resin composition that gives a molded article having excellent durability such as bending fatigue properties has not yet been known. The present invention solves all of the above disadvantages and has excellent durability such as weather resistance, mechanical strength, fatigue properties, especially bending fatigue properties even when a molded article is colored, and is used for outdoor applications, particularly for automobile exteriors. It is an object of the present invention to provide a long-fiber-reinforced polyolefin resin composition that can be suitably used for molded articles such as applications.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to obtain a long-fiber reinforced polyolefin resin composition which has solved the above-mentioned disadvantages, and as a result, obtained a hindered amine-based light-stable pigment which is colored with zinc sulfide and has a molecular weight of 1,000 or more. The present inventors have found that a composition containing an agent is extremely useful for solving the above problems, and have reached the present invention.

That is, the present invention has the following configuration. (1) On the basis of the composition, (A) the polyolefin resin should be 28 to 94.
98% by weight, (B) 5 to 60% by weight of reinforcing fiber in the polyolefin resin impregnated reinforcing fiber having a length of 2 to 50mm, (C) 0.01 to 10% by weight of zinc sulfide, and (D) a molecular weight of 1,000 or more A long fiber reinforced polyolefin resin composition containing 0.01 to 2% by weight of a hindered amine light stabilizer. (2) The long fiber reinforced polyolefin resin composition according to (1), wherein the polyolefin resin is a propylene homopolymer. (3) The long-fiber-reinforced polyolefin resin composition according to (1) or (2), wherein the polyolefin resin-impregnated reinforcing fiber is a polyolefin resin-impregnated reinforcing fiber. (4) Zinc sulfide is zinc sulfide with a purity of 98% by weight or more (1)
The long fiber reinforced polyolefin resin composition according to any one of (1) to (3). (5) A molded article obtained by molding the long fiber reinforced polyolefin resin composition according to (1). (6) The average fiber length of the reinforcing fibers derived from the polyolefin resin-impregnated reinforcing fibers in the molded product was maintained at 1 mm or more (5)
(7) The molded article according to (5) or (6), wherein the polyolefin resin is a propylene homopolymer. (8) The molded article according to any one of (5) to (7), wherein the polyolefin resin impregnated reinforcing fiber is a polyolefin resin impregnated reinforcing fiber. (9) The zinc sulfide is a zinc sulfide having a purity of 98% by weight or more (5)
The molded article according to any one of (1) to (8).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polyolefin resin used in the present invention is not particularly limited. Polyolefin resin is a carbon number of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc., usually about 2 to 10 α- The concept includes a crystalline homopolymer of olefin, a crystalline random copolymer or a crystalline block copolymer composed of two or more of these α-olefins, or a mixture composed of two or more of these polymers. is there. Among them, a propylene homopolymer, or a crystalline random copolymer or a crystalline block copolymer of propylene having a propylene content of 70% by weight or more and another α-olefin is practically versatile. I have. From the viewpoint of the reinforcing effect of the reinforcing fibers, it is preferable to use a modified polyolefin resin obtained by grafting an unsaturated carboxylic acid or an anhydride thereof to a polyolefin resin, or a mixture of the polyolefin resin and the modified polyolefin resin.

The reinforcing fibers used in the present invention include:
A wide variety of known materials such as glass fiber, carbon fiber, metal fiber, and polymer fiber can be used. These may be used alone or in combination of two or more. Glass fibers are preferred in terms of the reinforcing effect and the availability. As a continuous glass fiber bundle which is usually manufactured and marketed for resin reinforcement, glass roving can be mentioned. Usually, the average fiber diameter is 4-30 μm, the number of filament bundles is 400-10,000, and the tex count is 300-2.
Although it is 0,000 g / km, preferably the average fiber diameter is 9 to 23 μm,
The number of bundles is 1,000 to 6,000. From the viewpoint of the reinforcing effect, the surface is preferably subjected to silane treatment for imparting interfacial adhesion to the resin.

As a method for producing a reinforcing fiber impregnated with a polyolefin resin in the present invention, for example, a method is used in which a continuous glass roving is impregnated with a molten polyolefin resin and then pelletized to a length of 2 to 50 mm.
As a method for impregnating the reinforcing fiber bundle with the molten resin, any known method can be adopted as long as a good impregnation property can be obtained. A method of impregnating a molten resin by bringing a reinforcing fiber bundle into contact with the surface of a spreader under tension (Japanese Patent Publication No. 63-37694). For impregnation by passing through a space without contact (WO 97/1980)
5) and the like can be adopted, but the latter method is preferable in that there is little problem of fluffing during high-speed picking.

The reinforcing fibers in the polyolefin resin-impregnated reinforcing fibers are incorporated in the composition in an amount of 5 to 60% by weight. Preferably, it is 10 to 45% by weight. A masterbatch having a higher blending amount than the desired blending amount may be prepared, and the blending amount may be adjusted by the dry blend dilution. As the resin for dilution, the above-mentioned polyolefin resin can be used without limitation. After the dry blend dilution, it is preferable to directly supply the mixture to an injection molding machine without passing through an extruder from the viewpoint of maintaining the fiber length.

In the present invention, zinc sulfide is used as a white pigment. The zinc sulfide may be industrially produced and commercially available. Although the function and effect are not clear, from the viewpoint of weather resistance, those containing less than 2% by weight of impurities such as barium sulfate and zinc oxide, that is, purity of 98% by weight
It is preferable to select the above. In the case of coloring in a color other than white, other pigments can be appropriately blended with zinc sulfide and used. However, when titanium oxide is used in combination as a white pigment, the reinforcing fiber is damaged during coloring depending on the type of reinforcing fiber used in the present invention, so that titanium oxide is used within the range not impairing the object of the present invention. It is preferable to use it in combination with the composition.

The amount of zinc sulfide is determined depending on the desired degree of coloring, but is preferably 0.01 to 10% by weight in the composition. Preferably, it is 0.1 to 5% by weight. 0.01% by weight
If it is less than 3, the coloring becomes insufficient and the effect of improving the weather resistance is insufficient. Conversely, if the amount exceeds 10% by weight, there is no effect of improving the degree of coloring and weather resistance corresponding to the amount, and it is not economical. It is possible to prepare a coloring agent masterbatch having a blending amount higher than a desired blending amount, and to dry-dillute the reinforcing fiber with other blending components at the time of melt impregnation or molding. As the resin for dilution, the above-mentioned polyolefin resin can be used without limitation.

The present invention is characterized in that a hindered amine light stabilizer having a molecular weight of 1,000 or more is used. Specifically, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [[6- (1,1,3,3 -Tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6, 6-tetramethyl
-4-piperidyl) imino]], N, N'-bis (3-aminopropyl) ethylenediamine.2,4-bis [N-butyl-N- (1,2,2,6,
6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5
Triazine condensate, poly [(6-morpholino-s-triazine-
2,4-diyl) {(2,2,6,6-tetramethyl-4-piperidyl) imino}]-hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], Poly [(6-morpholino-s-triazine-
2,4-diyl) {(1,2,2,6,6-pentamethyl-4-piperidyl)
Imino}]-hexamethylene {(1,2,2,6,6-pentamethyl-4-
Piperidyl) imino}], but poly ((6-morpholino-s-triazo-2,4-diyl) {(2,2,6, 6-tetramethyl-4-
Piperidyl) imino}]-hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] is preferred.

The hindered amine light stabilizer having a molecular weight of 1,000 or more is incorporated in the composition in an amount of 0.01 to 2% by weight. Preferably, it is 0.05 to 1% by weight. If it is less than 0.01% by weight, sufficient weather resistance cannot be obtained, and if it exceeds 2% by weight, bleeding (blooming) to the surface of the molded product is likely to occur. A masterbatch having a higher blending amount than the desired blending amount may be prepared, and may be dry-blended together with other blending components at the time of molding. As the resin for dilution,
The aforementioned polyolefin resins can be used without limitation. The composition of the present invention, in addition to the above, if necessary, does not impair the purpose of the present invention, known additives usually blended with polyolefin resins such as antioxidants, ultraviolet absorbers, antistatic agents and the like. It can be blended in the range.

The method for producing a molded article obtained from the long-fiber-reinforced polyolefin resin composition of the present invention, that is, the molding method, includes known methods such as injection molding, extrusion, hollow molding, compression molding, and injection compression molding. Although the molding method can be applied without any limitation, the injection molding method is particularly preferable. The obtained molded product is suitably used for various purposes such as outdoor use such as automotive exterior use.

[0018]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited by these Examples. Evaluation method Average fiber length (volume average fiber length) of reinforcing fibers derived from the polyolefin resin-impregnated reinforcing fibers in the molded product A test piece of 50 mm x 50 mm x 2 mm was placed in an electric furnace set at an ambient temperature of 600 ° C for 2 hours. The resin portion was left incinerated and removed to obtain a residue. After the obtained residue was sufficiently stirred in water, a part of the glass fiber was sampled by a method of transferring it to a petri dish, and the glass fiber was subjected to measurement of the fiber length. The length was measured for 2,000 glass fibers. Using the measured values, a volume average fiber length value (Lv) was calculated from the following equation and used as an average fiber length. Lv = [ΣLi · Vi] / ΣVi = [ΣLi · π (D / 2) ² Li · ni] / [Σπ (D / 2) ² Li · ni] = [ΣLi ² · ni] / [ΣLi · ni] Li: length of fiber ni: number of fibers of length Li Vi: volume of fiber of length Li D: diameter of fiber

Tensile strength was determined according to JIS K-7113. A JIS No. 1 tensile dumbbell test piece was used. Flexural fatigue limit Measured according to ASTM D-671B method. Measurement was performed at 1,800 cycles / min using a Type 1 test piece. The stress value at 10 ⁷ cycles was bending fatigue limit. Weather resistance A test piece of 50 mm x 50 mm x 2 mm is set in a sunshine weather meter and subjected to accelerated exposure treatment for 2,000 hours under conditions of black panel temperature of 63 ° C and rain (12 minutes rainfall / 60 minutes cycle) to strengthen the surface. The presence or absence of fiber floating (GF floating) was observed. In addition, visual judgment was made on darkening. ◎: no darkening was observed, ○: little, but slight color difference was observed, x: marked darkening was observed, ×:
中間 was determined as halfway between と and ×.

Example 1 The following materials were prepared. Manufacture of glass fibers for polyolefin resin impregnated reinforcement Fibers for reinforcement derived from polyolefin resin impregnated reinforcement fibers have an average fiber diameter of 17 μm and a tex count of 2,310 g / km. In the tank, a modified propylene homopolymer [modified maleic anhydride, crystal melting point (DSC measurement): 160 ° C, melt flow rate (temperature 230)
° C, load 21.2N; hereinafter abbreviated as MFR. ): 200g / 10mi
n]. After impregnating the glass roving with the modified polyolefin resin, pull it out through a 2.3 mm diameter circular nozzle, cut it to a length of 6 mm after cooling, and use a glass fiber for glass fiber content impregnating and strengthening the polyolefin resin impregnated with 50% by weight. Obtained.

Colorant master batch 20% by weight of zinc sulfide (abbreviation in Table 1: ZnS-1) having a purity of 97.0% by weight as a white pigment, 10% by weight of phthalocyanine green as a green pigment, and MF as a polyolefin resin
A mixture of 70% by weight of a crystalline ethylene-propylene random copolymer (ethylene content: 4.5% by weight) having an R of 60 g / 10min is melt-kneaded and pelletized in an extruder at 200 ° C. to form a pellet of a colorant masterbatch. Obtained. Light stabilizer masterbatch Poly [(6-morpholino-s-triazo-2,4-diyl) {(2,2,6,6-tetramethyl-4-piperidyl) imino}]-having a molecular weight of 1600 as a light stabilizer Hexamethylene {(2,2,6,6-tetramethyl
4-piperidyl) imino}] (abbreviation in Table 1: LS-1) 10% by weight, and 90% by weight of a crystalline ethylene-propylene random copolymer (ethylene content 4.5% by weight) having an MFR of 60 g / 10min as a polyolefin resin % Was melt-kneaded and pelletized in an extruder at 200 ° C. to obtain pellets of a light stabilizer master batch. Polypropylene for dilution Crystalline homopolypropylene pellets having an MFR of 75 g / 10 min were used.

The final composition is as follows: 40% by weight of glass fiber derived from glass fiber for reinforcement by impregnation with polyolefin resin, 1.0% by weight of zinc sulfide having a purity of 97.0% by weight (abbreviation: ZnS-1 in Table 1),
[(6-morpholino-s-triazo-2,4-diyl) {(2,2,6,6-tetramethyl-4-piperidyl) imino}]-hexamethylene
{(2,2,6,6-tetramethyl-4-piperidyl) imino}]] (Table 1
Abbreviation in the middle: LS-1) 80% of the material to be 0.5% by weight
Weight%, material 5 weight%, material 5 weight%, material
Dry blend at 10% by weight, cylinder temperature 25
The test piece was applied to an injection molding machine set at 0 ° C., and a test piece was molded using a combination test piece mold. The average fiber length, tensile strength, bending fatigue limit, and weather resistance were evaluated using the obtained test pieces. As a result, each evaluation was good.

Example 2 40% by weight of the material, 5% by weight of the material, 5% by weight of the material and 50% by weight of the material so that the final composition is 20% by weight of the glass fiber derived from the glass fiber for reinforcing polyolefin resin impregnation.
A test piece was molded and evaluated in the same manner as in Example 1, except that the dry blend was performed at a weight percentage. as a result,
All evaluations were good.

Example 3 The final composition was poly [(6-morpholino-s-triazo-2,4-diyl) {(2,2,6,6-tetramethyl-4-piperidyl) imino}]-hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] (abbreviation in Table 1: LS-1) so as to be 1.0% by weight.
A test piece was molded and evaluated in the same manner as in Example 1, except that the material was dry-blended at a ratio of 80% by weight, the material was 5% by weight, the material was 10% by weight, and the material was 5% by weight. As a result, each evaluation was good.

Example 4 A material was prepared and molded in the same manner as in Example 1 except that zinc sulfide having a purity of 98.5% by weight (abbreviation: ZnS-2 in Table 1) was used as a white pigment in the material. An evaluation was performed. As a result, each evaluation was good.

Comparative Example 1 A material was prepared, molded and evaluated in the same manner as in Example 1 except that titanium oxide (abbreviation in Table 1: TiO ₂ ) was used as a white pigment in the material. As a result, the weather resistance was good, but the average fiber length of the glass fibers was short, and the strength and fatigue properties were poor.

Comparative Example 2 As a light stabilizer in the material, bis (2,2,6,6-
A material was prepared, molded and evaluated in the same manner as in Example 1, except that tetramethyl-4-piperidyl) sebacate (abbreviation in Table 1: LS-2) was used. As a result, the weather resistance was not improved at all.

[0028]

[Table 1]

[0029]

Industrial Applicability The long fiber reinforced polyolefin resin composition of the present invention contains a high molecular weight hindered amine light stabilizer and zinc sulfide as a white pigment, has excellent weather resistance, and has a long fiber even when molded. Because it is retained, it has excellent mechanical strength and fatigue properties, particularly durability such as bending fatigue properties. For this reason, it is suitably used for molded articles for outdoor use, particularly for automotive exterior use.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshimori Nakai 5-1, Goi Coast, Ichihara City, Chiba Prefecture Chisso Petrochemical Co., Ltd. Polymer Research Laboratory F term (reference) 4F072 AA02 AA08 AB09 AB14 AD04 AE10 AF02 AF28 AG05 AG13 AH51 AK15 AL02 4J002 AA002 BB001 BB021 BB111 BB121 BB141 BB151 BB161 BP021 CM013 DA016 DA066 DG027 DL006 EN008 EU088 FA042 FA046 FD043 FD048 GN00

Claims (9)

[Claims] (1) 28 to 94.98% by weight of a polyolefin resin, (B) 5 to 60% by weight of a reinforcing fiber in a polyolefin resin impregnated reinforcing fiber having a length of 2 to 50 mm, based on the composition. C) 0.01-10% by weight of zinc sulfide and (D) molecular weight
A long-fiber reinforced polyolefin resin composition containing 0.01 to 2% by weight of a hindered amine light stabilizer of 1,000 or more. 2. The long fiber reinforced polyolefin resin composition according to claim 1, wherein the polyolefin resin is a propylene homopolymer. 3. The fiber for reinforcing polyolefin resin impregnation,
A glass fiber for reinforcing polyolefin resin impregnation.
3. The long fiber reinforced polyolefin resin composition according to claim 1 or 2. 4. The long fiber reinforced polyolefin resin composition according to claim 1, wherein the zinc sulfide is zinc sulfide having a purity of 98% by weight or more. 5. A molded article obtained by molding the long fiber reinforced polyolefin resin composition according to claim 1. 6. The molded article according to claim 5, wherein the average fiber length of the reinforcing fibers derived from the polyolefin resin-impregnated reinforcing fibers in the molded article is maintained at 1 mm or more. 7. The molded article according to claim 5, wherein the polyolefin resin is a propylene homopolymer. 8. The fiber for reinforcing polyolefin resin impregnation,
A glass fiber for reinforcing polyolefin resin impregnation.
8. The molded article according to any one of 5 to 7. 9. The molded article according to claim 5, wherein the zinc sulfide is a zinc sulfide having a purity of 98% by weight or more.