JPH0524559A - Engine under cover - Google Patents

Abstract

PURPOSE:To provide an under cover which is light and excellent in rigidity and fire resistant by using synthetic resin containing thermoplastic resin containg high density polyethylene and polypropylene and a specified flame retardant and antimony oxide in a specified proportion. CONSTITUTION:An engine under cover 11 made of synthetic resin is formed of a fire resistant resin composition which is formed of 84-95wt.% of thermoplastic resin containing high density polyethylene PP and polypropylene HDPE, 4-12wt.% of a flame retardant containing halogenated phthalic acid imide derivative and brominated polystyrene and 1-4wt.% of antimony oxide. The inclusive rate of PP and HDPE is to be PP/HDPE=2/8-8/2 at weight ratio, and the inclusive rate of halogenated phthalic acid amide derivative and brominated polystyrene is to be 3/7-7/3, and the inclusive rate of the flame retardant and antimony oxide is to be 2-4. Consequently, it is possible to provide such an engine under cover as is light, excellent in impact strength and rigidity and has sufficient fire resistant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine undercover made of synthetic resin.

[0002]

2. Description of the Related Art In recent years, with the improvement of automobile performance, automobile components are required to be lighter, stronger, safer and more comfortable than ever before. Among these requirements, there is a strong demand for safety and weight reduction, and among various automobile parts, improvement for the engine undercover is particularly demanded.

[0003]

Conventionally, a thermoplastic resin such as an iron plate or polyethylene has been mainly used as a material for an engine undercover. However, the iron plate
Besides being heavy and an obstacle to weight reduction, it has the drawback of rusting. On the other hand, the thermoplastic resin is light in weight, but is inferior in impact strength and rigidity, and additionally has insufficient flame retardancy (self-extinguishing property), which causes a problem in safety. Therefore, conventionally, there has been a demand for an engine undercover that is made of a material that is lightweight, has excellent impact strength and rigidity, and has sufficient flame retardancy. Therefore, an object of the present invention is to provide an engine undercover that can satisfy these requirements at the same time.

[0004]

The engine undercover according to the present invention is characterized by comprising a flame-retardant resin composition containing the following components A, B and C. A: Thermoplastic resin containing high-density polyethylene and polypropylene ...... 84 to 95 wt% B: Flame retardant containing the following a and b …… 4 to 12 wt% a: Halogenated phthalimide derivative b: Brominated polystyrene C: Antimony Oxide: 1 to 4 wt% where A + B + C = 100 wt%

The high-density polyethylene (A) of the thermoplastic resin used in the present invention is not particularly limited in its physical properties, but in terms of MI (melt index).
It is preferably about 0.1 to 0.9. The polypropylene of the thermoplastic resin is preferably block propylene, and its physical properties are not particularly limited, but MI is preferably about 0.5 to 4.

The content ratio of this thermoplastic resin is 84 wt%
If it is less than 1, the impact resistance is lowered, the strength as an engine undercover is insufficient, and the molding workability at the time of molding a sheet made of a flame retardant resin composition into an engine undercover is deteriorated. Further, when the content exceeds 96 wt%, the flame retardancy is significantly reduced. The content ratio (PP / HDPE) of polypropylene (PP) and high-density polyethylene (HDPE) of this thermoplastic resin (A) is set to 2/8 to 8/2 (weight ratio), but it is difficult to deviate from this range. Flammability decreases.

Specific examples of the halogenated phthalimide derivative represented by the following chemical formula 1 in the flame retardant (B) are as follows:
The following compounds may be mentioned. For example, methylenebis (tetrabromophthalimide), ethylenebis (tetrabromophthalimide), propylenebis (tetrabromophthalimide), butylenebis (tetrabromophthalimide), benzidinebis (tetrabromophthalimide), Methylene bis (tetrachlorophthalimide), ethylene bis (tetrachlorophthalimide),
There are propylene bis (tetrachlorophthalimide), butylene bis (tetrachlorophthalimide), and the like, and among these, ethylene bis (tetrabromophthalimide) is particularly preferable.

[0008]

[Chemical 1]

The brominated polystyrene in the flame retardant (B) is not particularly limited in its degree of polymerization and bromine content.
Those having 3 or more bromines per styrene unit are preferred.

If the content of the flame retardant (B) containing a and b is less than 4% by weight, sufficient flame retardancy cannot be obtained. On the other hand, when the content exceeds 12 wt%, the impact resistance is lowered and the strength as an engine undercover is insufficient, and the molding processability at the time of molding a sheet made of a flame retardant resin composition into an engine undercover. To do. Further, the content ratio (a / b) of a and b in the flame retardant (B) is 3/7 to 7
The ratio is / 3 (weight ratio), but if it is less than 3/7, the flame retardancy decreases, and if it exceeds 7/3, the flame retardancy and the tensile elongation decrease, and the impact resistance also increases. It becomes low, and cracks easily occur in, for example, a falling ball test.

The antimony oxide (C) acts as a flame retardant aid, and specific examples thereof include diantimony trioxide (Sb ₂ O ₃ ) and diantimony tetroxide (S).
b ₂ O ₄ ), diantimony pentoxide (Sb ₂ O ₅ ) and the like. Among these, diantimony trioxide is particularly preferable. The content ratio of this antimony oxide (C) is 1 to
When it is out of the range of 4 wt%, the dispersibility of the flame retardant is lowered and the flame retardancy is lowered. The content ratio (B / C) of the flame retardant (B) and the antimony oxide (C) is 2 to 4 (weight ratio), but if it is out of this range, sufficient flame retardancy cannot be obtained.

In addition to the above A, B, and C, various additives and fillers may be added to the flame-retardant resin composition according to the present invention. For example, the additives include antioxidants, lubricants, ultraviolet absorbers, stabilizers, pigments and the like which are usually added to resin molded articles, and these can be used appropriately. Further, as the filler, talc, calcium carbonate, precipitated barium sulfate or the like can be appropriately used.

The method of mixing and kneading the raw materials when producing the flame-retardant resin composition according to the present invention is arbitrary. For example, in addition to the methods described in the examples below, HDPE and PP
(A), flame retardant (B), antimony oxide (C) are mixed and kneaded to prepare a masterbatch, and HDPE is added to this.
And the PP (A) may be mixed in an amount of 5 to 10 times with respect to the master batch to finally produce the resin composition according to the present invention. The method for molding the flame-retardant resin composition into the engine undercover is arbitrary. For example, after molding a sheet made of the flame-retardant resin composition, this sheet is molded into the engine undercover by vacuum or press molding. do it.

[0014]

EXAMPLES Examples 1 to 6 First, as raw materials, thermoplastic resins HDPE and PP, flame retardant halogenated phthalimide derivative and brominated polystyrene, flame retardant aid antimony oxide, dispersant and antioxidant. Were used and kneaded at a blending ratio shown in Tables 1 and 2 below to obtain resin pellets made of the flame-retardant resin composition according to each example. However, the compounding amount according to Example 9 was set such that the total amount of HDPE, PP, Cytex BT-93, Pyrocheck 68PB, and Sb ₂ O ₃ constituting the masterbatch was 1 part by weight, and HD was added to this masterbatch.
2.4 parts by weight of PE and 1.6 parts by weight of PP were added and diluted, and the mixture was mixed with a Beverly mixer to obtain the blending ratio shown in the table.

The kneading machine used here is Ikegai Tekko Co., Ltd.
Warner type PCM twin-screw kneader (screw diameter
45 mm). The screw rotation speed is 150 rpm, and the cylinder temperature during molding is 2 from the hopper side to the die side.
30 ℃, 250 ℃, 230 ℃, 220 ℃, 220 ℃, (Dice) 2
It had a distribution of 20 ° C. The density and melt index (MI) of the resin composition according to each example are as shown in Table 1. In addition, this MI was measured under the conditions of 230 ° C. and a load of 2160 g. In the table, the thermoplastic resin, the flame retardant and the flame retardant aid show wt% in the blending amount of each raw material, and the dispersant and the antioxidant show the parts by weight when the total of the above three parts is 100 parts by weight. ..

Specific examples of the halogenated phthalimide derivative used in the examples and the following comparative examples are shown below. Halogenated phthalimide derivative: Cytex BT-93 shown in Chemical formula 2 below (trade name, manufactured by Ethyl Corporation, substance name: 1,2-bis (tetrabromophthalimide) ethane)

[0017]

[Chemical 2]

Brominated polystyrene: Pyrocheck 68PB [trade name, manufactured by Nissan Ferro Organic Chemicals Co., Ltd.] shown in Chemical formula 3 below.

[0019]

[Chemical 3]

Antimony oxide: diantimony trioxide (Sb ₂ O ₃ ) dispersant: Cadenax GS90 (trade name, manufactured by Lion Corporation, substance name: glycerin monostearate) and Rheostat T-60 (trade name) , Lion Co., Ltd., substance name: sorbitan monostearate] Antioxidant ... Mark 2112 [trade name, manufactured by Adeka Argus Co., Ltd., substance name: Tris (2,4di-t-butylphenyl) phosphite ] And Mark AO-60 [trade name, manufactured by Asahi Denka Co., Ltd., substance name: tetrakis- [methylene-3- (3 ', 5'-di-tertiary-butyl-4'-
Hydroxyphenyl) propionate] methane

Next, test pieces were prepared using the resin pellets of the respective examples, and a tensile test, a bending test and an IZOD impact test were carried out. The results are shown in Tables 1 and 2. The tensile test is based on ASTM D638.
The tensile strength, the tensile elastic modulus, and the tensile elongation were measured in accordance with the above. The bending test is ASTM D7.
According to 90, bending strength and bending elastic modulus were measured. The Izod impact test was carried out on a notched one at 23 ° C. according to ASTM D256.

Next, the resin pellets of the respective examples were molded into two kinds of test pieces having different thicknesses (3.2 mm x 12.7 mm x 127 mm).
And 1.6 mm × 12.7 mm × 127 mm) were prepared and a combustion test was conducted. The results are shown in Tables 1 and 2. The injection molding machine used was FS50 (trade name) manufactured by Nissei Plastic Co., Ltd. The cylinder temperature during molding had a distribution of 190 ° C, 200 ° C, 210 ° C, and (die) 200 ° C from the hopper side to the die side.

The combustion test method is based on the UL (Underwri)
ters Laboratories Inc.) test standard UL94
Vertical test (V). The flammability is HB, V-2, V-1, V from bad to good.
The evaluation is divided into four stages of -0. Note that the thinner the test piece, the more likely it is to burn, so the conditions become stricter.

Next, a film (thickness: 20 to 50 μm, 50 mm × 50 mm) was prepared using the resin pellets of each example, and the dispersibility of the flame retardant was evaluated. The results are shown in Table 1. The molding machine used to make the film. It was a 50t compression molding machine manufactured by Toho Machine Industry Co., Ltd., and the heater temperature was 200 ° C. The dispersibility of the flame retardant depends on the diameter present in the film.
0.1-0.5mm white spot (aggregate due to poor dispersion of flame retardant)
It was done by counting the number of. In this dispersibility evaluation,
0 to 5 white dots were evaluated as O, 6 to 30 were evaluated as Δ, and 31 or more were evaluated as x.

Next, using the resin pellets of the respective examples,
Resin temperature 2 by single screw extruder (screw diameter 90mm)
Extruded sheet at 30 ~ 250 ℃ (thickness 1.5 mm, width 1050 m
After being formed into m), the sheet was subsequently passed between two rolls and cooled to 100 to 180 ° C. Then, the impact resistance of the sheet was evaluated in the following manner. The results are shown in Tables 1 and 2. The impact resistance was evaluated by 535 g of steel balls at −30 ° C. being naturally dropped onto the sheet from a height of 2 m and whether or not cracks were formed in the sheet. This falling ball test was performed 5 times on the sheets of the respective examples, and the number (x) of those in which no crack was generated is shown as x / 5.

Next, using this sheet, an engine under cover 11 having the shape shown in FIG. 1 was formed by press forming at a sheet temperature of 100 to 180 ° C. Then, the formability of the engine undercover 11 was evaluated.
The results are shown in Tables 1 and 2. With this evaluation of moldability,
○: Molding can be performed faithfully to the shape of the mold, △: Partial rounding occurs at the corners, ×… Roundness or breakage occurs at the entire corners,
Are shown respectively.

[0027]

[Table 1]

[0028]

[Table 2]

Comparative Examples 1 to 11 In the same manner as in the above Examples, various physical property tests and combustion tests were performed on test pieces made of the resin composition according to each Comparative Example, and the dispersibility of the flame retardant was evaluated for the film. , Further about the seat impact resistance and engine undercover
The moldability to 11 was evaluated. The results are shown in Table 3 below.
4 shows. However, as shown in the table, the raw materials used in each comparative example were the same as those in the examples, but the mixing ratio of each raw material was changed. That is, thermoplastic resin (HDPE and P
The compounding amount of at least one of P), the flame retardant (halogenated phthalimide derivative and brominated polystyrene), and antimony oxide is out of the range according to the present invention.

[0030]

[Table 3]

[0031]

[Table 4]

Consideration of Examples and Comparative Examples According to Examples 1 to 9 above, the flame-retardant resin composition according to each example comprises the raw material according to the present invention, and the content of each raw material is the same. Since it is within the range according to the invention, the test pieces according to each example have good physical properties as shown by the results of the tensile test, the bending test and the Izod impact test. Further, the film comprising the resin composition according to each example, in the evaluation of the dispersibility of the flame retardant, almost no white spots showing aggregates due to poor dispersion of the flame retardant are seen, and the dispersibility of the flame retardant is good. I know there is. Since the flame retardant is well dispersed in this way, the two types of test pieces for the combustion test according to each example have flame retardancy, as shown by the results of the combustion test.

Further, it can be seen that the sheets according to the respective examples had no cracks in the falling ball test and had good impact resistance. And, the molding workability when molding the engine under cover 11 using this sheet is ○ in any of the examples, and it is possible to mold faithfully to the mold shape without rounding at the corners. Is. Therefore,
Since the engine undercover 11 made of the flame-retardant resin composition of each example also has the properties of the above film, test piece and sheet, it has excellent tensile properties, bending properties and impact properties, and sufficient flame retardancy. have.

On the other hand, according to Comparative Example 1, since the content of the thermoplastic resin is less than the range according to the present invention, the Izod impact value is low and the corner portion is rounded so that the molding process is performed. There was a problem with sex. In addition, there was one cracked sheet in the falling ball test, and there was a problem in impact resistance. According to Comparative Example 2, since the content of the thermoplastic resin was larger than the range according to the present invention, the flame retardancy was poor.

According to Comparative Example 3, since the content of the flame retardant was less than the range according to the present invention, the flame retardancy was poor.
According to Comparative Example 4, since the antimony oxide was not contained, the flame retardancy was good when the thickness of the test piece was large in the combustion test, but the flame retardancy became poor when the thickness was thin. Further, the dispersibility of the flame retardant was poor. According to Comparative Example 5, since the content of antimony oxide is larger than the range according to the present invention, the flame resistance is good when the thickness of the test piece is large in the combustion test, but the flame resistance is small when the thickness is thin. Became bad.
Further, the dispersibility of the flame retardant was poor.

According to Comparative Example 6, the content of the thermoplastic resin is within the range according to the present invention, but since the content ratio of PP and HDPE (PP / HDPE) is less than the range according to the present invention, the flame retardancy is high. The sex was poor. According to Comparative Example 7, the content of the thermoplastic resin is within the range according to the present invention, but PP
And the content ratio of HDPE (PP / HDPE) was higher than the range according to the present invention, the flame retardancy was poor.

According to Comparative Example 8, the content of the flame retardant was within the range according to the present invention, but the content ratio of the halogenated phthalimide derivative (a) and the brominated polystyrene (b) (a
Since / b) is less than the range according to the present invention, the flame retardance is good when the thickness of the test piece is large in the combustion test, but the flame retardancy becomes poor when the thickness is thin. According to Comparative Example 9, the content of the flame retardant is within the range according to the present invention.
Since the content ratio (a / b) of b was larger than the range according to the present invention, the elongation rate in the tensile test and the Izod impact value were low, and the flame retardancy was poor. In addition, there were two sheets with cracks in the falling ball test, and there was a problem in impact resistance.

According to Comparative Example 10, the content of the flame retardant and the antimony oxide is within the range according to the present invention, but the content ratio (B / C) of the flame retardant (B) and the antimony oxide (C).
However, when the thickness of the test piece was large in the combustion test, the flame retardancy was good, but when the thickness was thin, the flame retardancy became poor. According to Comparative Example 11, the content of the flame retardant and the antimony oxide is within the range according to the present invention, but since the content ratio of B and C (B / C) is less than the range according to the present invention, it is difficult. The flammability was poor.

[0039]

The engine undercover according to the present invention is lightweight, has excellent impact strength and rigidity, and has sufficient flame retardancy.

[Brief description of drawings]

FIG. 1 is a perspective view of an engine undercover according to an embodiment of the present invention.

[Explanation of symbols]

 11 Engine under cover

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takesumi Nishio 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Rin Hayashi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Takashi Hirai 1-277 Kanda Izumi-cho, Chiyoda-ku, Tokyo Within 277 Calp Industry Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. An engine undercover comprising a flame-retardant resin composition containing the following components A, B, and C. A: Thermoplastic resin containing high-density polyethylene and polypropylene ...... 84 to 95 wt% B: Flame retardant containing the following a and b …… 4 to 12 wt% a: Halogenated phthalimide derivative b: Brominated polystyrene C: Antimony Oxide: 1 to 4 wt% However, A + B + C = 100 wt% Here, the content ratio of polypropylene (PP) and high density polyethylene (HDPE) of A is PP / HDPE =
2/8 to 8/2 (weight ratio), and the content ratio of a and b of B is a / b = 3/7 to 7/3 (weight ratio),
In addition, the content ratio of B and C is B / C = 2 to 4 (weight ratio).