JP3285481B2 - Automotive components made of polyacetal resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile-related member made of a polyacetal resin, in which a decrease in physical properties caused by a high temperature or in the presence of water or fuel is extremely small. More specifically, the present invention relates to an automobile-related member comprising a polyacetal resin composition containing a specific fibrous reinforcing material and a boric acid compound.

[0002]

2. Description of the Related Art As is well known, polyacetal resins have excellent physical properties such as mechanical properties and electrical properties, or chemical properties such as chemical resistance and heat resistance. In recent years, it has been used in a very wide field as a typical engineering resin.
However, with the expansion of the field in which the polyacetal resin is used, further improvement in the properties of the material has been required. For example, in a polyacetal resin molded article used under severe conditions such as a fuel system part, an engine peripheral part, an exterior part, etc. as an automobile-related member, deterioration of the polyacetal resin due to heat, fuel such as gasoline, rainwater, etc. In addition, a decrease in the interfacial adhesion between the polyacetal resin and the filler caused by the water content and a decrease in the mechanical physical properties associated with the decrease are seen, and improvements to these properties are desired. As means for improving such long-term durability, addition of various stabilizers and the like has been conventionally proposed. However, there is a problem that the effect is not sufficient or discoloration is remarkable, and improvement has been desired.

[0003]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, by mixing a fibrous filler and a specific boric acid compound with a polyacetal resin, The present inventors have found that a polyacetal automobile-related member having excellent durability can be obtained, and have completed the present invention. That is, the present invention relates to (A) 100 parts by weight of a polyacetal resin, (B) 3 to 200 parts by weight of a fibrous reinforcing material, and (C) orthoboric acid, metaboric acid, tetraboric acid and ditrioxide.
At least one boric acid compound selected from boron
The present invention relates to a polyacetal resin-made automobile-related member obtained by molding a polyacetal resin composition containing 0.001 to 3 parts by weight.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below. The polyacetal resin used in the present invention (A), a polymer compound that oxymethylene group a (-CH ₂ O-) as the main constituent unit, containing a small amount of other structural units polyacetal homopolymer, in addition to oxymethylene groups Polyacetal copolymer (block copolymer) or terpolymer. In the present invention, the polyacetal resin may be used by blending two or more of the above, if necessary, but a polyacetal copolymer is preferred from the viewpoint of moldability. For example, a polyacetal copolymer obtained by copolymerizing a comonomer component at 1 to 30% by weight, particularly 1 to 5% by weight, is preferable because it can maintain excellent thermal stability, mechanical strength and the like. The acetal copolymer may have not only a linear molecule but also a branched structure or a crosslinked structure. The viscosity of the polyacetal resin is not particularly limited as long as molding is possible, but in terms of the effect of improving the crystallization speed,
Those having an MI of 1 to 100 g / 10 min, particularly those having a MI of 5 to 50 g / 10 min are preferred. The comonomer component used for producing the polyacetal copolymer is not particularly limited, but one having a structure represented by the following general formula is generally used.

[0005]

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Wherein R ₁ , R ₂ , R ₃ , and R ₄ are the same or different substituents, and each represents a hydrogen atom, an alkyl group (having 1 to 5 carbon atoms and 0 to 3 hydrogen atoms being a halogen atom, Or an alkyl group substituted with a halogen, and R ₅ is a methylene group, an oxymethylene group, an alkyl group or an oxymethylene group, respectively (in this case, p =
Integer of 0 to _{3), - (CH 2) q} -OCH 2 (q = 1~4 integer) or - by _{(O-CH 2 -CH 2)} q -OCH 2 (q = 1~4 integer) The divalent group shown (in this case, p = 1) is shown. Examples of the comonomer include ethylene oxide, epichlorohydrin, 1,3-dioxolan, diethylene glycol formal, 1,4
-Butanediol formal, 1,3-dioxane, propylene oxide and the like. As the fibrous reinforcing material of the component (B), any fibrous reinforcing material generally used for a thermoplastic resin can be used. Examples of the fibrous filler include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium,
Inorganic fibrous substances such as fibrous materials of metals such as copper and brass are exemplified. In particular, glass fiber or carbon fiber is a preferable fibrous reinforcing material for obtaining the polyacetal resin-related automotive parts of the present invention. The compounding amount of the fibrous reinforcing material as the component (B) is 3 to 200 parts by weight, preferably 5 to 150 parts by weight, particularly preferably 10 to 100 parts by weight, per 100 parts by weight of the polyacetal resin. If the amount is less than 3 parts by weight, the mechanical strength is insufficient, and if it exceeds 200 parts by weight, molding becomes difficult. Further, the range of the fiber diameter of these fibrous reinforcements is preferably 5 to 30 μm, and a particularly preferable fiber diameter is 10 μm.
2020 μm. If it is less than 5 μm, adverse effects such as deterioration of formability due to thickening, and if it exceeds 30 μm, toughness is reduced.

The boric acid compound as the component (C) includes orthoboric acid, metaboric acid, tetraboric acid and diboron trioxide, and commercially available products can be used. The amount of the boric acid compound added was 0.001 per 100 parts by weight of the polyacetal resin.
To 3 parts by weight, preferably 0.01 to 2 parts by weight, particularly preferably 0.01 to 1 part by weight. If the amount is less than 0.001 part by weight, the desired effect cannot be obtained, and if it exceeds 3 parts by weight, the thermal stability deteriorates.

The polyacetal resin composition used in the present invention may further contain various known additives. For example, various colorants, antioxidants, release agents, nucleating agents, antistatic agents,
Other surfactants, various polymers and the like. In addition, if it is within the range that does not significantly reduce the performance of the molded article aimed at the present invention, known inorganic, organic, plate-like metal,
It is also possible to compound one or more kinds of fillers such as powders and granules. Examples of such inorganic fillers include, but are not limited to, glass beads, talc, mica, white mica, wollastonite, calcium carbonate, and the like.

The polyacetal resin molded article of the present invention can be easily prepared by a known method generally used as a conventional resin molded article preparation method. For example, after mixing each component, it is kneaded and extruded with a single-screw or twin-screw extruder to prepare pellets. Thereafter, a molding method, once pellets having different compositions (master batch) are prepared,
Any method can be used, such as a method of mixing (diluting) the pellets in a predetermined amount and subjecting the mixture to molding to obtain a molded article having a desired composition after molding. In addition, in the preparation of the composition used for such a molded article, part or all of the base polyacetal resin is ground, mixed with other components, and then subjected to extrusion or the like. This is a preferred method for improving the quality.

[0010] The resin molded article of the present invention can be used for any application in which it is considered that there is a concern that physical properties may be deteriorated due to high temperature or fuel or moisture. It is suitably used for equipment that frequently becomes hot or frequently comes into contact with water or fuel. Specific examples include fuel parts (tanks, filters, pumps, swirl tanks, etc.), clips, gears, switches, and the like.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Examples 1 to 10 and Comparative Examples 1 to 5 In a polyacetal resin (manufactured by Polyplastics Co., Ltd., trade name "Duracon"), the fibrous reinforcing material and the boric acid compound shown in Table 1 were added at the ratio shown in Table 1. After mixing, the mixture was melt-kneaded by a twin-screw extruder to prepare a pellet-shaped composition.
Next, a test piece (ASTM tensile test piece type IV) was formed from this pellet by injection molding, and the following evaluation was performed. Table 1 shows the results. Further, for comparison, a similar test piece was molded and evaluated even when the boric acid compound was not added. Table 2 shows the results. Evaluation items <Tensile strength and elongation> A test piece was molded using the following molding machine and molding conditions, and left for 48 hours at a temperature of 23 ° C and a humidity of 50%.
It measured according to TM-D638. Molding machine: Toshiba Corporation IS80 Molding conditions Nozzle C1 C2 C3 Cylinder temperature (℃) 200 190 180 160 Injection pressure 64MPa Injection speed 1.0m / min Mold temperature 80 ℃ <Heat aging> Tensile test molded under the above molding conditions Place the pieces in a 140 ° C constant temperature bath, remove them after 1200 hours, and leave them at a temperature of 23 ° C and a humidity of 50% for 48 hours.
Measured according to 638. <Hot water> 80 ° C
Immersed in a hot water tank, and taken out after 1200 hours, at a temperature of 23 ° C,
After being left for 48 hours under the condition of 50% humidity, the measurement was performed according to ASTM-D638. <Gasoline resistance> Tensile test specimens molded under the above molding conditions
It was immersed in regular gasoline at 60 ° C., taken out after 720 hours, left for 48 hours at a temperature of 23 ° C. and a humidity of 50%, and measured in accordance with ASTM-D638.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

From the results shown in the table, it is clear that when a fiber-reinforced polyacetal resin molded article to which a boric acid compound is added is used, excellent durability is exhibited as a member related to automobiles.

Claims (4)

(57) [Claims] (A) 100 parts by weight of a polyacetal resin, (B) 3 to 200 parts by weight of a fibrous reinforcing material, (C) orthoboric acid, metaboric acid, tetraboric acid and ditrioxide.
At least one boric acid compound selected from boron
An automotive-related member made of a polyacetal resin obtained by molding a polyacetal resin composition containing 0.001 to 3 parts by weight of a polyacetal resin composition. 2. The polyacetal resin-related automobile member according to claim 1, wherein the fibrous reinforcing material is glass fiber. 3. The polyacetal resin-related automobile member according to claim 1, wherein (B) the fibrous reinforcing material is a carbon fiber. 4. The automobile-related member made of a polyacetal resin according to claim 1, wherein the fibrous reinforcing material (B) has a fiber diameter of 5 to 30 μm.