JP2846141B2 - Automotive bumper manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ethylene copolymer,
Waste materials such as used materials and recovered materials for automobile bumpers composed of a propylene polymer (including an ethylene-propylene block copolymer) and talc and containing a propylene-based resin as a main component (hereinafter, simply referred to as “waste materials”). The present invention relates to a method of manufacturing an automobile bumper using a thermoplastic polymer composition which improves the fluidity, flexural modulus and surface hardness by blending the same with a thermoplastic polymer composition which enables the reuse of waste materials for the bumper.

[0002]

2. Description of the Related Art Automobile bumper materials mainly composed of propylene resin are mainly composed of ethylene-propylene rubber, propylene polymer and talc, and a small amount of polyethylene, a different kind of rubber and a filler are added as required. For example, Japanese Patent Publication No. 60-3420
JP, JP-B-59-49252, JP-B-61-
276840, the composition described in JP-B-63-65223, etc. are used, but when the automobile is scrapped, the bumper is crushed and granulated, and if it is intended to be reused as a bumper material, The quality improvement over the years has led to many difficulties in using it as is. More specifically, in recent years, as bumper products have become thinner and thinner, it is difficult to mold with low-flowable compositions in the past, and the flexural modulus is insufficient for use in thin-walled products. Therefore, there is a difficulty in maintaining the shape of the bumper. Furthermore, the past compositions have the disadvantage that the surface hardness of the product is low and the bumpers are easily scratched, which makes them extremely unsuitable as current bumper materials requiring good appearance. For this reason, the waste material of the bumper which has passed for a long time as described above can only be used by blending the currently used bumper composition with a limited amount within a range that does not significantly impair the performance of the product. ,
This is a major obstacle in reusing bumper waste, which is expected to occur in large quantities in the future.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a waste material of an automobile bumper containing the above-mentioned propylene resin as a main component.
It seeks to improve low flow, flexural modulus and surface hardness, and to enable large amounts of waste material to be reused as bumper material.

[0004]

Means for Solving the Problems The present inventors have developed a method of improving the fluidity, flexural modulus and surface hardness of a waste material of the above-mentioned automobile bumper while maintaining the impact resistance thereof, thereby enabling reuse. After various investigations, waste materials were ethylene copolymers,
By blending a specific composition consisting of a propylene polymer and talc at a specific weight ratio, the flowability, flexural modulus and surface hardness of the waste material can be improved, and the processability during injection molding is good. It is hard to be scratched,
The inventors have found that a bumper having sufficient rigidity can be obtained and completed the invention. That is, the present invention crushes waste materials of propylene-based resin bumpers for automobiles, and adds a thermoplastic polymer component to an ethylene-based copolymer and a propylene polymer (including an ethylene-propylene block copolymer).
In the fractionation with o-dichlorobenzene, the sum of the component (A) soluble at 40 ° C. and the component (B) insoluble at 40 ° C. and soluble at 110 ° C. is 50 to 70 parts by weight. And the weight ratio of component (A) to component (B) [component (A) / component (B)] is 0.5 or less, and 50 to 30 parts by weight of component (C) insoluble at 110 ° C. A thermoplastic polymer composition comprising 100 parts by weight of a certain component and 15 to 35 parts by weight of talc is added to 1 part by weight of the waste material.
A method for manufacturing an automobile bumper, which comprises mixing and molding 0 to 300 parts by weight . Ethylene-based copolymer The ethylene-based copolymer used in the present invention has an MFR (2
30 ° C.) for 1 to 10 g / 10 minutes (preferably 2 to 8 g /
10 minutes) is suitably used in terms of moldability and impact resistance, and the crystallinity is not too high from the viewpoint of compatibility with a large amount of ethylene-propylene rubber contained in waste bumper materials. since it is important, 60 to 100 [° C. as measured by differential scanning calorimeter (preferably 65 to 90 ° C.) having a melting point of a density of 0.92 g / cm ³ or less (preferably 0.91 g / cm ³ or less) Is preferably used in terms of performance of maintaining impact resistance of bumper waste material and improving surface hardness. The ethylene copolymer is prepared by a gas-phase fluidized-bed method, a solution method, a slurry method, or a pressure of 200 kg / cm ² or more in the presence of an ion polymerization catalyst such as a Ziegler-type catalyst, a Phillips-type catalyst, and a Kaminski-type catalyst. Fifteen
A product obtained by copolymerizing ethylene and an α-olefin by applying a production process such as high-pressure ion polymerization at 0 ° C. or higher, and having a melting point in the above range regardless of the content of the α-olefin. Is preferably used. Α-olefin copolymerized with ethylene has 3 carbon atoms.
~ 8 1-olefins, for example, propylene,
Butene-1,3-methylbutene-1, pentene-1,4
-Methylpentene-1, hexene-1, heptene-1,
Octene-1 and the like. The α-olefin in this case is 1
The type does not need to be limited, and a multi-component copolymer using two or more types may be used. This ethylene copolymer is mainly
Is composed of a crystalline component and an amorphous rubber component,
The amorphous rubber component therein is the thermoplastic rubber in the present invention.
Corresponds to component (A) which is an amorphous component in the coalesced composition
You. In addition, the crystalline component of the ethylene copolymer is
Medium crystalline component in thermoplastic polymer composition
Component (B).

Propylene polymer The propylene polymer used in the present invention has an MFR of 80.
180 g / 10 min (preferably 100 to 150 g / 1
0 minutes) and a propylene-ethylene block copolymer having an ethylene content of 1.5 to 8% by weight (preferably 2 to 7% by weight) in that the impact resistance of the bumper waste material is maintained and the processability is improved. The density of the crystalline propylene polymerized portion is 0.907 g / cm ³ or more (preferably 0.908 g / cm ^3).
/ Cm ³ or more) is suitably used in terms of improving the flexural modulus and surface hardness of waste bumper material. The MFR of the propylene polymer may be adjusted at the time of polymerization, or adjusted with an organic peroxide such as diacyl peroxide or dialkyl peroxide after polymerization. In addition, this propylene polymer, maleic anhydride,
It may be a copolymer containing another unsaturated monomer such as methacrylic acid or vinyltrimethoxysilane by copolymerization (graft or random), or a blend of these copolymers. In particular, crystalline polypropylene grafted with maleic anhydride or vinyltrimethoxysilane,
When used by mixing with the propylene polymer, there is an effect of improving the surface hardness. A highly stereoregular catalyst is used for the production of the propylene polymer. A typical production method of the above catalyst includes a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and further treating the same with various electron donors and electron acceptors, and an organoaluminum compound and an aromatic compound. Combination with aromatic carboxylic acid esters (JP-A-56-100806, JP-A-56-12)
0712, JP-A-58-104907),
And a method of a supported catalyst in which titanium tetrachloride and various electron donors are brought into contact with magnesium halide (Japanese Patent Laid-Open No.
-63310, JP-A-63-43915,
A known method such as that described in JP-A-63-83116) is used. This propylene polymer is mainly amorphous
Pyrene polymer component and propylene polymer component with low crystallinity
And a highly crystalline propylene polymer component.
The amorphous propylene polymer component therein is used in the present invention.
Component which is a non-crystalline component in a thermoplastic polymer composition
(A), which is equivalent to
The propylene polymer component is a thermoplastic polymer in the present invention.
Corresponds to the component (B) which is a medium crystalline component in the composition,
The propylene polymer is a highly crystalline propylene polymer
The high crystal content in the thermoplastic polymer composition of the present invention
It corresponds to the component (C) which is a sex component.

[0006] In the separation with o-dichlorobenzene, the two types of polymer components are classified into a component (A) soluble at 40 ° C and a component (A) insoluble at 40 ° C and soluble at 110 ° C ( The sum of B) is 50 to 70 parts by weight, and the component (A)
And the weight ratio (component (A) / component (B)) of component (B) to component (B) is 0.5 or less, and 50% of component (C) insoluble at 110 ° C.
It is blended so as to satisfy 〜30 parts by weight.
In the present invention, if the sum of the components (A) and (B) is less than the above (that is, the component (C) exceeds the above), the impact resistance is poor when blended with waste pampers. It is inappropriate because the rate is poor. If the weight ratio of the component (B) to the component (A) [component (A) / component (B)] exceeds the above range, the surface hardness of the bumper waste material cannot be sufficiently improved, which is inappropriate. In the present invention, if the intrinsic viscosity ([η]) of the component (C) is high, the fluidity of the bumper waste cannot be sufficiently improved, and the molding temperature needs to be increased, which causes an increase in the molding cycle. The component (C) preferably has an intrinsic viscosity of 1.5 dl / g or less (preferably 1.2 dl / g or less). The crystallinity of the propylene polymer is defined as an index of the ratio of the highly crystalline polypropylene when the polypropylene polymerized part in the component (B) obtained by using ¹³ C-NMR is defined as the component (D). (Amount of component (C) / (amount of component (C) + amount of component (D))) is 0.7 or more (preferably 0.1%).
75 or more) is preferable from the viewpoint of improving the surface hardness of the bumper waste material. The ethylene-based copolymer and the propylene polymer used in the present invention may be a mixture of two or more of each component as long as the component ratio of these components obtained by solvent separation is within the above range. Absent. Similarly, if the component ratio by solvent fractionation is within the above range, ethylene-propylene rubber or styrene rubber may be used in combination as needed.

The talc used in the present invention is produced by dry pulverization and then dry classification, and has an average particle size of 5 μm or less (preferably 0.5 to 3 μm) and a specific surface area of 3.5 m.
Those having a ratio of ² / g or more (preferably 3.5 to ⁶ m ² / g) are suitable. If the average particle size is more than the above, impact resistance tends to be inferior, and if the specific surface area is less than the above, the flexural modulus tends to be insufficient. The average particle size is a particle size value when the cumulative amount is 50% by weight read from a particle size cumulative distribution curve measured using a liquid phase sedimentation type light transmission method (for example, CP type manufactured by Shimadzu Corporation). The specific surface area is a value measured by an air permeation method (for example, a constant pressure ventilation type specific surface area measuring device SS-100 manufactured by Shimadzu Corporation). The amount of the talc is 10% in total of the ethylene copolymer and the propylene polymer.
15 to 35 parts by weight relative to 0 parts by weight (preferably 20 to 35 parts by weight)
30 parts by weight). If the amount is less than the above, the bending elastic modulus of the bumper waste cannot be sufficiently improved, and if the amount exceeds the above, the impact resistance of the bumper waste cannot be maintained. Talc may be used without treatment, but various organic titanate-based coupling agents, silane-based coupling agents, fatty acids, fatty acid metal salts, and fatty acids are used for the purpose of improving the adhesion or dispersibility with the polymer. Those treated with an ester or the like may be used.

[0008] In addition to the above components, other additional components can be added to the composition used in the present invention as long as the effects of the present invention are not significantly impaired. Other additional ingredients include:
Additives usually incorporated into the thermoplastic polymer composition, such as processability stabilizers, antioxidants, UV absorbers, light stabilizers,
Various kinds of soaps such as metal soaps, antistatic agents, lubricants, nucleating agents, pigments and pigment dispersants, etc., and also known to give higher flexural modulus than talc, fibrous potassium titanate can fibrous magnesium Oki sheet Sarufe <br/> DOO, whiskers and carbon fibers such as fibrous aluminum borate is also added as needed.

The composition used in the present invention is produced by kneading using an ordinary extruder, a Banbury mixer, a roll, a Brabender, a kneader, or the like, but is preferably produced using a twin-screw extruder. Such a composition is blended in an amount of 10 to 300 parts by weight (preferably 25 to 150 parts by weight ) with respect to 100 parts by weight of waste bumper, and molded by a usual injection molding method to form a bumper. If the amount is too small, the fluidity, flexural modulus, and surface hardness cannot be sufficiently improved, and the amount is unsuitable. On the other hand, if the amount is too large, the impact resistance is impaired. The blend of the waste material and the thermoplastic polymer composition used in the present invention has an MFR of 10 g / 10
Min., The flexural modulus is 10,000 kg / cm ² or more,
A material having a Rockwell hardness of 40 or more and an Izod impact value at −30 ° C. of 5 kg · cm / cm or more is suitably used in terms of bumper moldability, shape retention, scratch resistance and impact resistance. . The waste material of the bumper is a propylene polymer resin as a main component, modified with an ethylene-propylene rubber or talc, and molded into a bumper using a composition obtained by adding other necessary components, and formed for 5 years. It has passed the above, and preferably has an MFR of 6 g / 1.
0 minutes or more, flexural modulus of 7,000 kg / cm ² or more,
It has physical properties such as a Rockwell hardness of 25 or more and an Izod impact value at −30 ° C. of 5 kg · cm / cm or more. For example, waste materials of bumpers manufactured using the compositions described in JP-B-59-49252 and JP-B-60-3420 correspond to this.

[0010]

The present invention will be specifically described below with reference to examples. The solvent fractionation in the present invention was performed according to the following procedure. 5 g of sample and 2,6-di-t-butyl antioxidant
1.5 g of p-phenol was added to 1.5 g of o-dichlorobenzene.
The solution was dissolved in a liter at 140 ° C., and then filtered at 140 ° C. using a 0.45 μm Teflon filter to filter out insoluble components such as filler. After re-dissolving the filtrate at 140 ° C, Celite (# 545)
300 g was added, and the mixture was cooled to room temperature at a rate of 10 ° C./hour with stirring to coat the surface of Celite. The coated celite was filled into a cylindrical column, and the same concentration of the antioxidant was added to o-dichlorobenzene, which was transferred into the column.
And was separated by elution. After fractionation, a large amount of methanol was added, and the mixture was filtered with a 0.45 μm Teflon filter and dried under vacuum to weigh each section. The ratio of the classification categories was determined based on the total weight of each category.

The various measuring methods used in the present invention are as follows. The measuring methods (9) to (12) below are methods for evaluating bumper performance. (1) Melting point (melting temperature): A differential scanning calorimeter (for example, Model 910 DSC manufactured by DuPont) was charged with 10 mg of a sample, and +
After heating to 180 ° C, at a constant rate of 10 ° C for 1 minute-
Cool to 100 ° C. Thereafter, the temperature is raised at a constant rate of 20 ° C. for one minute, and the peak position of the obtained thermogram is defined as the melting point. (2) Intrinsic viscosity: 0.2% by weight of the antioxidant is added to o-dichlorobenzene, and 0.1 to 0.3 g at 140 ° C.
The concentration was measured in the range of / dl and extrapolated to zero concentration. (3) Polypropylene content in component (B): ¹³ C-NMR
The spectrum was determined using the integrated signal intensity derived from polypropylene carbon near 46.5 ppm of TMS standard. (4) MFR: 2.1 according to ASTM-D1238.
It was measured at 230 ° C. using a 6 kg load. (5) Density: Measured at 23 ° C. according to ASTM-D1505. (6) Flexural modulus: 23 according to ASTM-D790
Measured in ° C. (7) Surface hardness: 23 ° C. according to ASTM-D785
Was evaluated on the R-scale. (8) Impact resistance: -30 in accordance with ASTM-D256
It evaluated by the Izod value in ° C. (9) Bumper formability: weight 5kg, total length 1,780m
m, the both ends of a 450 mm wide plate-like body are attached to the tip portions 1a, 1b.
The length 1, which is bent at the position of 850 mm
A 780 mm U-shaped bumper 1 (see FIG. 1) was molded using an injection molding machine with a mold clamping force of 4,000 tons, and evaluated with the shortest molding cycle time at which a product with good appearance was obtained. (10) Evaluation method of shape retention of bumper: Bumper tip 1 when bumper 1 immediately after molding and removal from mold is placed on two support bars 2a and 2b arranged in parallel at an interval of 800 mm.
The deformation amount A of a was measured and evaluated. (Refer to Fig. 2) (11) Method for evaluating the scratch resistance of the bumper: From the time the bumper was formed until the coating process, handle the bumper with military gloves. A case concealed by painting was judged as pass, and a case not concealed was judged as unacceptable. (12) Impact resistance evaluation method for bumpers: Federal Regulation, US Federal Law, Title 49-b,
Pass / fail was determined based on CHAPTER5 and PART581.

Examples 1-6, Comparative Examples 1-6 The materials shown in Table 1 were blended with the compositions shown in Table 2, and
0.1 parts by weight of -di-t-butyl-p-phenol, 0.1 parts by weight of tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, And 0.5 part by weight of carbon black were mixed and mixed for 5 minutes by a super mixer manufactured by Kawada Seisakusho, and then kneaded and granulated at 210 ° C. by an FCM twin-screw kneader manufactured by Kobe Steel to obtain a composition. Next, 5
The waste material of the front bumper of the 7-year Corolla II was mechanically pulverized and kneaded and granulated at 210 ° C. with the above-described twin-screw kneader, and this composition was blended at a ratio shown in Table 2 to obtain a bumper. In order to confirm that it has the required physical properties, the injection molding machine with a mold clamping force of 100 tons has a molding temperature of 22
Various test pieces were prepared at 0 ° C., and the performance was evaluated according to the above-described measurement method. Further, an automobile bumper weighing 5 kg was molded at a molding temperature of 200 to 230 ° C. using an injection molding machine having a mold clamping force of 4,000 tons, and the performance was evaluated according to the method described above. The evaluation results are as shown in Tables 2 and 3 .

[0013]

[Table 1]

[0014]

[Table 2]

The component (A) is an amorphous component in the thermoplastic polymer composition of the present invention and mainly corresponds to an amorphous rubber component and an amorphous propylene polymer component of an ethylene copolymer. I do. Component (B) is a medium crystalline component in the thermoplastic polymer composition of the present invention, and mainly corresponds to a crystalline component of an ethylene copolymer and a propylene polymer component having low crystallinity. Component (C) is a highly crystalline component in the thermoplastic polymer composition of the present invention, and corresponds to a propylene polymer component having high crystallinity.

[0016]

[Table 3]

[0017]

According to the present invention, the specific composition used in the present invention is blended with the waste material of an automobile bumper containing a propylene resin as a main component, so that the fluidity, the flexural modulus and the flexural modulus can be improved without impairing its impact resistance. The surface hardness can be improved, the workability during the injection molding is good, the scratch is hardly damaged, and a bumper having sufficient rigidity can be obtained. In addition, the specific composition used in the present invention has a higher cooling and solidification rate due to a higher proportion of the high crystalline component (C) as compared with the conventional thermoplastic polymer composition. The cooling time can be shortened, and the production speed of the molded article can be greatly improved. Specifically, the weight ratio of the thermoplastic polymer composition used in the present invention to the waste material of a bumper containing a propylene-based resin as a main component [composition used in the present invention / bumper waste material] is 0.1 to 3%. By blending in the range, the MFR is preferably 10 g / 10
Minutes or more, the flexural modulus is 10,000 kg / cm ² or more, Rockwell hardness is 40 or more, and the Izod impact value at -30 ° C. is 5 kg / cm / cm or more, while maintaining good impact resistance. It is possible to obtain a bumper molded body having good moldability and improved rigidity and scratch resistance.

[Brief description of the drawings]

FIG. 1 is a perspective view of a bumper test piece used in evaluating the shape retention of a bumper.

FIG. 2 is a side view when the shape retention of the bumper is measured using the bumper test piece of FIG.

Continued on front page (72) Inventor Takao Nomura 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Hiroki Sato 1 Toho Town, Yokkaichi City, Mie Prefecture Yokkaichi Yuka Co., Ltd. Inside the Research Institute (72) Inventor Akihiko Uchikawa 1 Toho-cho, Yokkaichi-shi, Mie Prefecture Mitsubishi Yuka Corporation Inside the Yokkaichi Research Institute (72) Ikuo Tsutsumi 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Oil Corporation Inside the Yokkaichi Research Institute (72) Inventor Yukitaka Goto 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Yuka Co., Ltd. Inside the Yokkaichi Research Institute (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 23/00 -23/36

Claims (6)

(57) [Claims] 1. A waste material of a propylene resin bumper for automobiles is pulverized, and a thermoplastic polymer component is composed of an ethylene copolymer and a propylene polymer (including a propylene-ethylene block copolymer). In the fractionation using o-dichlorobenzene, the sum of the component (A) soluble at 40 ° C. and the component (B) insoluble at 40 ° C. and soluble at 110 ° C. is 50 to 70 parts by weight, and When the weight ratio of (A) to component (B) [component (A) / component (B)] is 0.
5 or less, and the component (C) insoluble at 110 ° C.
100 parts by weight of the composition, which is 30 parts by weight, and talc 1
5 to 35 parts by weight of a thermoplastic polymer composition,
A method for producing an automobile bumper, comprising mixing 10 to 300 parts by weight with respect to 100 parts by weight and molding. 2. The method according to claim 1, wherein the ethylene copolymer has a melting point of 60 to 100 ° C. as measured by a differential scanning calorimeter. 3. The method according to claim 1, wherein the intrinsic viscosity of the component (C) is 1.5 dl / g or less. 4. When the polypropylene polymerization part in the component (B) determined by using ¹³ C-NMR is defined as a component (D),
The production method according to claim 1, wherein the component (C) and the component (D) satisfy the relationship of the following formula. (Amount of component (C) / (amount of component (C) + amount of component (D)))> 0.7 5. The method according to claim 1, wherein the talc has an average particle size of 5 μm or less and a specific surface area of 3.5 m ² / g or more. 6. A blend of a waste material and a thermoplastic polymer composition having an MFR of 10 g / 10 min or more and a flexural modulus of 10,
000 kg, / cm ² or more, Rockwell hardness 40 or more,
The method according to claim 1, wherein an Izod impact value at -30 ° C is 5 kg · cm / cm or more.