JP5232050B2 - How to improve oil resistance and demoldability of automotive air ducts - Google Patents

Description

  The present invention relates to an automotive air hose (air duct) composed of an olefinic thermoplastic elastomer (hereinafter also referred to as “TPO”), and a method for improving oil resistance of the air hose and demolding in injection molding.

  Rubber hoses and thermoplastic elastomer air hoses are used in some of the ducts that supply air to automobile internal combustion engines. In recent years, thermoplastic elastomers (especially TPO) that excel in material recyclability and light weight. ) Made of air hose is desired. Such an automobile air hose is usually bent or has an undercut portion. However, thermoplastic elastomers generally tend to be inferior in physical properties such as strength and elongation as compared to rubber, so the demolding property is low, and the molded product may stretch when the molded product is injection molded from the mold. The problem of breaking is known.

  As a technique for solving such a problem, for example, International Publication WO2005 / 16626 (Patent Document 1) discloses a technique in which a core mold of a mold is divided in an axial direction and the core mold is removed in stages. A method for improving the demoldability of a TPO air hose is disclosed. However, even in this method, depending on the degree of undercut of the bent portion or the bellows-shaped portion of the air hose, it may be difficult to remove the TPO air hose, and it is desired to further improve the demoldability. .

  Furthermore, in air hose injection molding, in order to improve the demolding property, a method for improving the mold releasing property between the mold and the molded product is also performed by a method of spraying a mold release agent on the mold. Yes. However, even this method does not lead to sufficient demoldability.

  On the other hand, depending on the use location of an automotive air hose, engine oil contained in blow-by gas tends to adhere to the inside of the air hose, or engine oil that leaks during replacement tends to adhere. However, since TPO has low oil resistance, absorbs engine oil, swells, and easily decreases in rigidity and strength, the case where it can be applied to an air hose has been limited.

International Publication WO2005 / 16626 (Claims)

  Accordingly, an object of the present invention is to provide a method for improving oil resistance and demolding property in injection molding of an automotive air hose composed of an olefinic thermoplastic elastomer (TPO), as well as an automotive vehicle excellent in demolding property and oil resistance. To provide an air hose.

  Another object of the present invention is to improve the oil resistance of an automotive air hose composed of TPO and having an undercut portion, and the method of improving the mold release from the core mold in injection molding, as well as excellent mold release and oil resistance. To provide an air hose for automobiles.

  Still another object of the present invention is to provide an automotive air hose that has high flexibility and is excellent in scratch resistance and tear resistance.

  As a result of intensive investigations to achieve the above-mentioned problems, the present inventors have formulated a composition composed of a specific graft copolymer and a fatty acid amide into TPO, so that the oil resistance and injection molding of an automotive air hose can be achieved. The present inventors have found that the demoldability can be improved and completed the present invention.

  That is, the method of the present invention is based on the graft copolymer formed of a trunk segment composed of a propylene polymer and a branch segment composed of a nitrogen-containing vinyl polymer on the olefin thermoplastic elastomer (A). By blending the graft copolymer composition (B) containing the union (B1) and the fatty acid amide (B2) and injection molding, the oil resistance and demolding property of the automotive air hose are improved. The graft copolymer (B1) may be formed of a continuous phase and a dispersed phase dispersed in a granular form in the continuous phase, and the average particle size of the dispersed phase may be about 0.001 to 10 μm. The graft copolymer (B1) may be formed of a trunk segment composed of a propylene-based block copolymer and a branch segment composed of a nitrogen-containing vinyl polymer. The fatty acid amide (B2) may be a fatty acid amide having 10 to 25 carbon atoms. The ratio (weight ratio) between the graft copolymer (B1) and the fatty acid amide (B2) may be about the former / the latter = 50/50 to 99/1. The method of the present invention may be a method capable of improving the demoldability of the hose having a bent portion and / or an undercut portion (such as a bellows portion) in the injection molding of the hose. In the method of the present invention, 1-50 parts by weight of the graft copolymer composition (B) may be blended with 100 parts by weight of the olefin-based thermoplastic elastomer (A).

  The present invention provides a hose composed of an olefinic thermoplastic elastomer (A) and a graft copolymer composition (B), wherein the graft copolymer composition (B) is composed of a propylene polymer. Also included is an automotive air hose comprising a graft copolymer (B1) and a fatty acid amide (B2) formed of a branched segment composed of a trunk segment and a nitrogen-containing vinyl polymer.

  In the present specification, the term “undercut” usually means that an area where the movement trajectory of the mold overlaps with the molded product when the mold is removed, and the mold cannot be removed without elastically deforming the molded product. It means a part, and the bellows part or the like corresponds to the undercut part.

  In the present invention, since a composition comprising a specific graft copolymer and a fatty acid amide is blended, the oil resistance of an air hose composed of an olefinic thermoplastic elastomer (TPO) and the demolding property in injection molding are improved. it can. In particular, even if the hose is an automotive air hose having an undercut portion, the demolding property (particularly, the demolding property with the core mold) can be improved. Furthermore, the obtained hose has high flexibility (elastic deformation) and is excellent in scratch resistance and tear resistance.

FIG. 1 is a schematic sectional view showing an example of an automotive air hose to which the present invention is applied. 2 is a schematic cross-sectional view of an injection mold for molding the automobile air hose of FIG.

  In the present invention, the oil resistance and demoldability of an automotive air hose can be improved by blending the graft copolymer composition (B) and injection molding the olefinic thermoplastic elastomer (A).

(Automobile air hose)
The method of the present invention is useful for a hose made of TPO and obtained by injection molding, particularly a hose having a bent portion or an undercut portion (such as a bellows portion) that is difficult to remove. As an example of such a hose, an automotive air hose can be exemplified, and FIG. 1 is a schematic sectional view showing an example of an automotive air hose to which the present invention is applied.

  The hollow cylindrical air hose 1 includes a bellows portion 2 (undercut portion) that occupies a substantially central region in the length direction (the axial center direction of the hose), and a non-bellows portion 3a that extends from both ends of the bellows portion 2. 3b. The bellows portion 2 has a structure in which a plurality of crest portions 2a having a large diameter and a plurality of trough portions 2b having a small diameter are alternately formed along the axial direction. On the other hand, each of the non-bellows portions 3a and 3b has a substantially smooth surface and a structure bent with respect to the length direction. Further, reinforcing ribs 4a and 4b are integrally formed on the non-accordion portions 3a and 3b along the circumferential direction on the outer peripheral surface near the opening (end) of the hose. In the air hose 1, both openings of the hose are connected and fixed to an engine body or an air cleaner (both not shown) by a fastener (not shown), respectively, and used as an air duct.

  Typical dimensions of such an automotive air hose 1 include a hose length of about 50 to 500 mm (preferably 100 to 300 mm), a hose inner diameter of about 20 to 100 mm (preferably 30 to 80 mm), and a bellows portion meat. The thickness is about 0.5 to 3 mm (preferably 0.8 to 2 mm), and the thickness of the non-accordion portion 5 is about 1.5 to 7 mm (preferably 2 to 5 mm). Furthermore, the peak height of the bellows part 2 (the dimension in the radial direction between the peak part 3 and the valley part 4) is, for example, about 3 to 15 mm, preferably about 5 to 12 mm.

  The air hose 1 is integrally molded by injection molding using a polyolefin-based thermoplastic elastomer (TPO) as a molding material, and has a hardness according to JIS K6301 (spring type A type) of Hs (JIS A) 50 to 95 (particularly An elastomer having a degree of 55 to 90) is used.

  FIG. 2 shows a schematic sectional view of an injection mold 10 for injection molding the air hose 1 of FIG. The mold 10 is a mold having a cavity 14 that is a cavity corresponding to the outer shape of the air hose 1 (a cavity matching the product shape) inside, and is in contact with the outer peripheral surface of the air hose 1. A cavity mold 11 for forming the outer peripheral surface shape of the air hose and a core mold 12 for contacting the inner peripheral surface of the air hose and forming the inner peripheral surface shape of the hose.

  The cavity mold 11 has a structure that can be opened and closed by a cavity mold 11a and a cavity mold 11b that are equally divided into a pair of upper and lower sides (or a pair of left and right). When the cavity mold 11a and the cavity mold 11b are closed, the cavity mold 11a has a hollow shape having a shape corresponding to the shape of the outer peripheral surface of the air hose 1, and the cavity mold 11 is divided after the air hose is molded. Then, the mold is opened (not shown).

  The core mold 12 is a cylindrical shape including a shape corresponding to the shape of the inner peripheral surface of the air hose 1, and is divided into a short core mold 12a and a long core mold 12b in the axial direction. The contact surface 13 with which the end surfaces to be abutted is formed. Further, the short core mold 12a has a smooth surface side portion for forming a non-bellows portion of the air hose on the contact surface 13 side, and the long core mold 12b extends from the center portion to the contact surface 13. A surface concavo-convex structure for forming the bellows portion of the air hose is formed on the side portion close to the base portion, and a base portion that does not contact the air hose is formed at the end portion opposite to the contact surface 13 side.

  A molding method using this injection mold can use a conventional method of injecting molten TPO into the cavity 14, cooling and solidifying, then opening the mold and taking out the air hose 1 as a molded product. As for the details of the method using such divided molds, the method described in the aforementioned International Publication No. WO2005 / 16626 (Patent Document 1) can be used.

  In particular, in the case of an air hose for automobiles, since there are bent portions and undercut portions (portions that cannot be demolded unless the molded product is elastically deformed and expanded in diameter due to the bellows shape), demolding is difficult.

  Specifically, after injecting molten TPO into the cavity 14, cooling and solidifying, first, the cavity core 11b (or 11a) is opened and the short core mold 12b is pulled out. Thereafter, the other cavity mold 11a is opened. In this step, the mold opening of the cavity mold 11 is performed in such a manner that the cavity mold 11a and the cavity mold 11b divided into a pair are vertically moved in a direction substantially perpendicular to the length direction of the hose. It can be easily removed. On the other hand, the short core mold 12a can be pulled out in the length direction of the hose, and since there is no bent portion or undercut portion in that direction, it can be removed relatively easily.

  Next, since the long core mold 12b has a bent portion and a bellows portion, it is difficult to remove the long core mold 12b by the same pulling method as the short core mold 12a. Usually, a method using an extraction jig is used. . That is, in this method, a substantially cylindrical extraction jig is inserted into the hose on the side where the short core mold 12a is pulled out, and air or compressed air is inserted between the long core mold 12b and the inner peripheral surface of the molded body. Is blown to expand the molded body. Further, a gap is formed between the expanded molded body and the long core mold 12b, and the undercut state is released. In this state, the long core mold 12b is pulled out to complete the demolding.

  However, in TPO, the slipperiness and flexibility are not sufficient, and even in the method using the extraction jig, deformation and damage of the molded body due to expansion, the long core mold 12b in the bent portion and the bellows portion, and the molded body. The molded body is easily damaged by contact. On the other hand, in the method of the present invention, by adding the graft copolymer composition (B) described later to TPO, the releasability (sliding property) of the molding material is improved and flexibility is provided. However, since the strength such as tear resistance is improved, the undercut portion can be removed easily and smoothly. In particular, the method of the present invention is effective not only in the mold removal method using the extraction jig but also in the mold removal method not using the extraction jig.

(A) Olefin-based thermoplastic elastomer (TPO)
In the present invention, the TPO used in the air hose is not particularly limited as long as it is a conventional TPO having the above-mentioned hardness. For example, a rubber component that is a hard segment olefin polymer and a soft segment Can be used. Such an elastomer may be a copolymer of both components or a blend.

The olefin polymer includes an α-olefin homo- or copolymer having 2 or more carbon atoms. Examples of such olefins include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, and 4-methyl-1. _-C2-10 olefins such as pentene and 1-octene. These olefins can be used alone or in combination of two or more. Among these olefins, α-C _2-4 olefins such as ethylene and propylene are widely used.

  Preferred examples of the olefin polymer include ethylene polymers such as polyethylene and ethylene-propylene copolymer, and propylene polymers. Furthermore, a propylene polymer may be used from the viewpoints of compatibility with the graft copolymer composition (B) containing a propylene polymer and strength. Examples of the propylene polymer include a copolymer of propylene and an α-olefin having 2 or 4 or more carbon atoms such as polypropylene, propylene-ethylene copolymer, and propylene-butene copolymer.

  The rubber component includes olefin rubber, diene rubber (polybutadiene, styrene-butadiene rubber, etc.), acrylic rubber, butyl rubber, nitrile rubber, natural rubber and the like. These rubber components can be used alone or in combination of two or more. Of these rubber components, olefin rubber is preferred from the viewpoint of compatibility with the olefin polymer.

  Examples of the olefin rubber include ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene copolymer rubber (EPDM), ethylene-butene copolymer rubber, and ethylene-1-butene-nonconjugated diene. Examples include copolymer rubber, propylene-1-butene-nonconjugated diene copolymer rubber, and polyisobutylene rubber. Examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene. These olefin rubbers can be used alone or in combination of two or more. Among these olefin rubbers, ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene copolymer rubber and the like are widely used.

  The ratio (weight ratio) between the olefin polymer and the rubber component is, for example, olefin polymer / rubber component = 10/90 to 90/10, preferably 20/80 to 80/20, more preferably 30. / 70 to 70/30 or so.

  The TPO includes other thermoplastic resins (for example, polyolefin resins such as polypropylene resins and polyethylene resins), plasticizers (non-aromatic mineral oils or the like) as long as the characteristics of the olefin component are not impaired. A low molecular weight synthetic softening agent, etc.).

  Commercially available TPO products include, for example, the trade name “Mirasutoma” (Mitsui Chemicals), the trade name “Santoprene” (AES Japan), and the trade name “Sumitomo TPE” (Sumitomo). Chemical Co., Ltd.), trade name "Cataloy" (manufactured by Sun Allomer Co., Ltd.) and the like.

(B) Graft Copolymer Composition In the present invention, the graft copolymer composition (B) is blended with the olefinic thermoplastic elastomer (A) to remove the air hose for automobiles from injection molding. An automotive air hose that can improve moldability and oil resistance and has improved mold release and oil resistance by such a method includes an olefinic thermoplastic elastomer (A) and a graft copolymer composition (B). It is configured. Furthermore, the graft copolymer composition (B) includes a graft copolymer (B1) and a fatty acid amide (B2).

(B1) Graft copolymer The graft copolymer (B1) is formed of a trunk segment composed of a propylene polymer and a branch segment composed of a nitrogen-containing vinyl polymer.

The propylene-based polymer includes propylene homopolymer or copolymer. Examples of the copolymerizable monomer in the copolymer include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, 4 Α-C _2-16 olefins other than propylene such as methyl-1-pentene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, cyclic olefins (norbornene, ethylidene norbornene, cyclopentene, Cyclopentadiene, cyclohexene, etc.), dienes (butadiene, isoprene, 1,4-pentadiene, etc.), vinyl monomers in vinyl polymers described later, and the like. These copolymerizable monomers can be used alone or in combination of two or more. Of these copolymerizable monomers, α-olefins, particularly C _2-10 olefins (particularly α-C _2-6 olefins) such as ethylene and butene are preferred.

  Examples of the propylene polymer include polypropylene, propylene-ethylene copolymer, propylene-butene copolymer, propylene-ethylene-butene terpolymer. The form of the copolymer may be random copolymerization, but block copolymerization is preferred.

  The propylene-based polymer may be an atactic polymer, or may have a stereoregular structure such as an isotactic polymer, a syndiotactic polymer, or a polymer obtained using a metallocene catalyst. Among these, a propylene-based polymer having an isotactic structure is preferable from the viewpoint of simplicity.

  In the copolymer, the ratio (molar ratio) between propylene and a copolymerizable monomer (particularly α-olefin) is, for example, propylene / copolymerizable monomer = 30/70 to 99/1, preferably 40. / 60 to 90/10, more preferably about 50/50 to 80/20 (particularly 55/45 to 70/30). In the present invention, a block copolymer having such a copolymerization ratio is particularly preferable from the viewpoint of ease of synthesis of the graft copolymer.

  In the present invention, the propylene polymer that is the trunk segment is graft-polymerized with a vinyl monomer containing at least a nitrogen-containing vinyl monomer, and the nitrogen-containing vinyl polymer is used as a branch segment. Thus, the affinity with both components of TPO and fatty acid amide can be improved, so that the leaching out of fatty acid amide on the surface of the hose can be suppressed and the surface can be provided with lubricity to improve the demoldability.

  In addition to nitrogen-containing vinyl monomers, vinyl monomers include aromatic vinyl monomers, (meth) acrylic acid and salts thereof, (meth) acrylic acid ester monomers, crotonic acid ester monomers Monomers, vinyl ester monomers, vinyl ether monomers, unsaturated carboxylic acid monomers, vinyl silane monomers and the like are included.

  Examples of the nitrogen-containing vinyl monomer include a vinyl cyanide monomer, an amino group-containing vinyl monomer, a vinylamide monomer, and a vinyl monomer having a nitrogen-containing heterocyclic ring. .

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, alkyl styrene (for example, methyl styrene, dimethyl styrene, ethyl styrene, isopropyl styrene, t-butyl styrene, etc.), α-alkyl substituted styrene (for example, α -Methylstyrene, α-ethylstyrene, etc.), divinylbenzene and the like.

Examples of the (meth) acrylic acid ester monomer include C ₁ such as alkyl (meth) acrylate [methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. _-20 alkyl (meth) acrylate, etc.], hydroxy group-containing (meth) acrylate [hydroxyalkyl (meth) acrylate such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, polytetramethylene Polyalkylene glycol (meth) acrylate such as glycol (meth) acrylate], alkoxy (meth) acrylate [ethoxy (meth) acrylate, etc.], aryl (meth) acrylate [feature Nyl (meth) acrylate and the like], glycidyl (meth) acrylate and the like.

Examples of the crotonic acid ester monomers include, for example, crotonic acid alkyl esters (such as crotonic acid C _1-20 alkyl esters such as methyl crotonic acid and ethyl crotonic acid), crotonic acid hydroxyalkyl esters (hydroxyethyl crotonic acid, crotonic acid, and the like). Hydroxypropyl and the like).

Examples of the vinyl ester monomer include saturated or unsaturated C _4-24 fatty acid vinyl such as vinyl acetate, vinyl propionate, vinyl laurate, vinyl stearate, vinyl oleate and the like.

Examples of vinyl ether monomers include C _1-10 alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether.

  Examples of the unsaturated carboxylic acid monomer include (anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid and the like.

  Examples of the vinylsilane monomer include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane and the like.

  These vinyl monomers can be used singly or in combination of two or more, but it is necessary to include at least a nitrogen-containing vinyl monomer among these vinyl monomers. In the present invention, by including the nitrogen-containing vinyl monomer, the affinity with the fatty acid amide (B2) is improved, and bleeding out of the fatty acid amide (B2) can also be suppressed.

  Among the nitrogen-containing vinyl monomers, examples of the vinyl cyanide monomer include (meth) acrylonitrile.

Examples of the amino group-containing vinyl monomer include N, N-dialkylamino C _2-4 alkyl such as N, N-dimethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate ( And (meth) acrylate.

Examples of the vinylamide monomer include (meth) acrylamides {for example, (meth) acrylamide, N-alkyl (meth) acrylamide [for example, N—C such as N-methylacrylamide, N-isopropyl (meth) acrylamide, etc. _1-10 alkyl (meth) acrylamide etc.], N, N-dialkyl (meth) acrylamide [for example, N, N-diC _1-10 such as N, N-dimethyl (meth) acrylamide, N, N-diethylacrylamide, etc. Alkyl (meth) acrylamide etc.], dialkylaminoalkyl (meth) acrylamide [eg di-C _1-10 alkylamino C _2-4 alkyl (meth) acrylamide such as dimethylaminopropyl (meth) acrylamide], N-alkoxyalkyl (Meth) acrylic Mido [e.g. N- _C1-4 alkoxy _C1-10 alkyl (meth) acrylamide such as N-ethoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, etc.], N- (dialkylaminoalkyl) ( Meth) acrylamide [eg N- (diC _1-10 alkylamino C _2-4 alkyl) (meth) acrylamide etc.] such as N- (2-dimethylaminoethyl) (meth) acrylamide]}, unsaturated dicarboxylic acid Examples thereof include amides (for example, maleic acid amide).

  Examples of the vinyl monomer having a nitrogen-containing heterocyclic ring include, for example, a (meth) acrylate having a nitrogen-containing heterocyclic ring {for example, a (meth) acrylate having a 4- to 10-membered heterocyclic ring containing only nitrogen as a hetero atom [ For example, nitrogen-containing 5-8 such as N- (meth) acryloylpyrrolidine, N- (meth) acryloylpyrrole, N- (meth) acryloylimidazole, N- (meth) acryloylpiperidine, N- (meth) acryloylhexamethyleneimine (Meth) acrylates having a membered heterocyclic ring], (meth) acrylates having a 4- to 10-membered heterocyclic ring containing nitrogen and oxygen as hetero atoms [for example, nitrogen and oxygen containing N- (meth) acryloylmorpholine, etc. A (meth) acrylate having a 5- to 8-membered heterocyclic ring, etc.], and a nitrogen-containing compound having a vinyl group. Ring compounds [for example, nitrogen-containing 4- to 10-membered heterocyclic compounds having a vinyl group (for example, nitrogen-containing 5- to 8-membered heterocyclic rings having a vinyl group such as N-vinylpyrrolidone, N-vinylimidazole, vinylpiperidine, vinylpyridine, etc. Compounds), nitrogen-containing 5- to 12-membered condensed heterocyclic compounds having a vinyl group (for example, 6- to 10-membered condensed heterocyclic compounds having a vinyl group such as N-vinylphthalimide, vinylquinoline, etc.)], unsaturated dicarboxylic acids, etc. Acids (for example, maleimide etc.) etc. are mentioned.

  These nitrogen-containing vinyl monomers can be used alone or in combination of two or more.

  Further, the nitrogen-containing vinyl monomer may be combined with other vinyl monomers (especially aromatic vinyl monomers such as styrene), and the ratio (molar ratio) of both is the nitrogen-containing vinyl. Monomer / other vinyl monomer = can be selected from the range of about 100/0 to 1/99, for example, 90/10 to 5/95, preferably 70/30 to 10/90, more preferably It is about 50/50 to 20/80 (particularly 55/45 to 30/70). In particular, when an aromatic vinyl monomer such as styrene is combined with a nitrogen-containing vinyl monomer, a graft copolymer having an excellent balance between moldability, rigidity and oil resistance can be obtained.

  In the graft copolymer (B1) formed of such a trunk segment and a branch segment, one segment forms a multiphase structure in which fine particles are formed in the other segment as a matrix. Good. Any segment of the trunk segment and the branch segment may form a matrix (continuous phase).

  The shape of the dispersed phase is not particularly limited, and may be (true) spherical, ellipsoidal, fibrous, or indefinite shape, but (true) spherical or ellipsoidal is preferable. The average particle diameter of the dispersed phase is, for example, about 0.001 to 10 μm, preferably about 0.01 to 5 μm, more preferably about 0.05 to 3 μm (particularly 0.1 to 1 μm). When the particle size of the dispersed phase is not within this range, the dispersibility in the blend with TPO is lowered, and the appearance and the rigidity of TPO tend to be lowered.

  The ratio (weight ratio) between the trunk segment and the branch segment in the graft copolymer (B1) can be selected from the range of trunk segment / branch segment = 99/1 to 1/99, for example, stem segment / branch segment = 99. / 1 to 5/95, preferably 95/5 to 20/80, more preferably about 90/10 to 30/70 (particularly 80/20 to 50/50). When there are too few trunk segments, the dispersibility of the graft copolymer in TPO tends to be lowered, and the appearance of the molded product tends to be lowered. Conversely, when there are too many trunk segments, the improvement effect on TPO tends to be insufficient.

  The melt flow rate (MFR) of the graft copolymer (B1) is, for example, 0.01 to 500 g / 10 minutes, preferably 0.1 to 300 g / 10 minutes, more preferably 1 to 200 g / 10 minutes (particularly 5 ˜100 g / 10 min). If the MFR is out of this range, the compatibility with TPO tends to decrease, or the appearance of the molded product tends to deteriorate. The MFR can be measured in accordance with JIS K 7210 under the condition M [test temperature 230 ° C., nominal load 2.16 kgf (21.18 N)] in Appendix A Table 1 of JIS K 7210.

(B1) Graft Copolymer Production Method As the graft copolymer (B1) production method, a chain transfer method or ionizing radiation irradiation method generally known as a grafting method can be used. Specifically, the following method is preferable from the viewpoint that the grafting rate is high, secondary aggregation due to heat can be suppressed, and simple points.

  That is, in the present invention, a dispersion obtained by dispersing a propylene polymer in a solvent contains at least a vinyl monomer containing a nitrogen-containing vinyl monomer, a radical polymerization organic peroxide, and a radical polymerization initiator. Add a solution, impregnate the propylene polymer particles with the vinyl monomer, radical polymerization organic peroxide and radical polymerization initiator, and perform radical polymerization with the vinyl monomer in the propylene polymer particles. A graft copolymer is obtained by copolymerization with a functional organic peroxide, followed by melting and mixing.

  The polymerization temperature of the vinyl monomer can be selected according to the type of the vinyl monomer and the radical polymerization initiator, and is not particularly limited. For example, it is 50 to 100 ° C., preferably 60 to 90 ° C., more preferably. It is about 65-80 degreeC (especially 70-75 degreeC).

  In the present invention, since the vinyl monomer and the radical polymerization initiator are impregnated into the propylene polymer particles prior to the polymerization, the radical polymerization is not initiated and the radical polymerization initiator is substantially decomposed. The suspension may be heated with stirring under conditions that do not occur at a temperature of, for example, 40 to 70 ° C, preferably 50 to 65 ° C, and more preferably about 60 to 65 ° C. The heating time for impregnation is, for example, about 30 minutes to 6 hours, preferably about 1 to 5 hours.

  Furthermore, when the impregnation rate of the vinyl monomer and the radical polymerization initiator reaches 20% by weight or more (particularly 30% by weight or more) of the addition amount, the temperature of the suspension is, for example, 50 to 80 ° C., The grafting precursor may be obtained by raising the temperature to 60 to 75 ° C, more preferably about 70 to 75 ° C, and copolymerizing a vinyl monomer in the propylene polymer particles. The heating time is, for example, about 1 to 10 hours, preferably about 3 to 8 hours.

  Furthermore, the obtained grafting precursor is heated at about 100 to 300 ° C. (especially 120 to 250 ° C.) and melt-mixed, whereby the propylene polymer is used as the trunk segment and the vinyl polymer is used as the branch segment. A graft copolymer is obtained. The graft ratio of the graft copolymer may be, for example, about 5 to 100%, preferably about 10 to 100%, and more preferably about 20 to 100%. As a method for melt-mixing the precursor, an extrusion kneading method using a conventional single-screw or twin-screw extruder or a roll kneading method can be used.

  As the solvent, any aqueous solvent or hydrophobic solvent can be used as long as it does not inhibit the reaction. From the viewpoint of simplicity, for example, water, lower alcohol (for example, ethanol or isopropanol), ketone ( For example, water or a mixed solvent of water and a lower alcohol (particularly water) is particularly preferable from the viewpoint of convenience and the like.

  The proportion of the propylene-based polymer is, for example, 1 to 100 parts by weight, preferably 5 to 80 parts by weight, and more preferably about 10 to 50 parts by weight with respect to 100 parts by weight of the solvent. The proportion of the vinyl monomer is, for example, 1 to 400 parts by weight, 5 to 300 parts by weight, more preferably 10 to 100 parts by weight (particularly 20 to 60 parts by weight) with respect to 100 parts by weight of the propylene polymer. Degree.

  Furthermore, a suspending agent may be used in order to improve the dispersibility of the propylene-based polymer. The suspending agent can be selected according to the type of solvent. In the case of an aqueous solvent, for example, a water-soluble polymer (polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, hydrophilic cellulose derivative, etc.), a polyhydric alcohol (glycerin, etc.) ) Etc. are available. The ratio of the suspending agent is, for example, about 0.01 to 5 parts by weight (particularly 0.1 to 1 part by weight) with respect to 100 parts by weight of the aqueous solvent.

  Examples of the radical polymerization initiator include conventional radical polymerization initiators such as organic peroxides (for example, benzoyl peroxide, o-methoxybenzoyl peroxide, o-chlorobenzoyl peroxide, lauroyl peroxide, di-3,5,5-trimethyl). Hexanoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, etc.), inorganic peroxides (eg hydrogen peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, etc.), azo compounds {for example 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2-Methyl- - (2-hydroxyethyl) - propionamide], 2,2'-azobis [2- (2-imidazolin-2-yl) propane], etc.} and the like. The organic or inorganic peroxide may be combined with a reducing agent to form a redox polymerization initiator. Examples of the reducing agent include L-ascorbic acid, L-sorbic acid, sodium metabisulfite, ferrous sulfate, Rongalite and the like.

These radical polymerization initiators can be used alone or in combination of two or more. Among these radical polymerization initiators, a radical polymerization initiator having a decomposition temperature of 40 to 90 ° C. for obtaining a 10-hour half-life (for example, di-C ₄ such as di-3,5,5-trimethylhexanoyl peroxide). _-10 alkyl peroxydicarbonates etc.) are preferred.

  In the present invention, a radical polymerizable organic peroxide is added in addition to the radical polymerization initiator from the viewpoint of improving the compatibility with TPO. The radical polymerizable organic peroxide is not particularly limited as long as it has a radical polymerizable group such as a vinyl group and an OO bond, but the decomposition temperature for obtaining a 10-hour half-life is 40 to 90 ° C. From the point of view, peroxycarbonate having a vinyl group can be preferably used. Examples of the peroxycarbonate having a vinyl group include alkyl peroxy (meth) acrylic carbonates such as t-butylperoxymethacrylic carbonate, alkylperoxy (meth) acryloyloxyalkyl carbonates such as t-butylperoxy (meth) acryloyloxyethyl carbonate, Examples thereof include alkyl peroxy (meth) acrylic carbonates such as t-butyl peroxyallyl carbonate. These radically polymerizable organic peroxides can be used alone or in combination of two or more.

  The ratio of the radical polymerization initiator is, for example, 100 parts by weight of the vinyl monomer (when the radical polymerizable organic peroxide is included, the total of the vinyl monomer and the radical polymerizable organic peroxide), The amount is 0.01 to 8 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably about 0.1 to 1 part by weight. The proportion of the radically polymerizable organic peroxide is, for example, 20 parts by weight or less, preferably 0.1 to 15 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer. (Particularly 1 to 5 parts by weight).

(B2) Fatty Acid Amide The fatty acid amide (B2) may be a fatty acid amide having 10 to 25 carbon atoms from the viewpoint of compatibility with TPO and availability. Such fatty acid amides, for example, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, C _10-24 saturated fatty acid amides such as Behemin acid amide, myristoleic acid amide, palmitoleic acid C _10-24 unsaturated fatty acid amides such as amides, petroceric acid amides, oleic acid amides, linoleic acid amides, elaidic acid amides, gatrenic acid amides, arachidonic acid amides, erucic acid amides, brassicinic acid amides, methylenebisstearic acid amides, Examples thereof include C _1-4 alkylene bis-saturated or unsaturated fatty acid amides such as methylene bis-oleic acid amide, ethylene bis-stearic acid amide, and ethylene bis-oleic acid amide.

These fatty acid amides can be used alone or in combination of two or more. Of these fatty acid amides, unsaturated C _16-24 fatty acid amides such as oleic acid amide and erucic acid amide, and C _1-4 alkylene bis C _16-24 unsaturated fatty acid amides such as ethylene _bisoleic acid amide are preferred and high. From the viewpoint of lubricity, C _16-22 unsaturated fatty acid amides such as oleic acid amide are particularly preferred.

  The ratio (weight ratio) between the graft copolymer (B1) and the fatty acid amide (B2) is the former / the latter = 50/50 to 99/1, preferably 55/50 to 95/5, more preferably 60/40. It is about -90/10 (especially 70 / 30-85 / 15). If the proportion of the graft copolymer (B1) is too small, the stiffness of the TPO will decrease, and the bleedout of the graft copolymer composition (B) will occur. Conversely, if the proportion is too large, the demolding effect will decrease. .

(B) Graft copolymer composition The graft copolymer composition (B) is obtained by melt-mixing the fatty acid amide (B2) into the graft copolymer (B1) or a grafting precursor thereof. .

  As the melt mixing method, an extrusion kneading method using a conventional single-screw or twin-screw extruder, a roll kneading method, or the like can be used. The temperature in the melt mixing is about 70 to 250 ° C (particularly 100 to 220 ° C). If this temperature is too low, melting will be incomplete, melt viscosity will be high and mixing will be insufficient, and phase separation and delamination will easily occur. Conversely, if it is too high, the fatty acid amide is likely to be decomposed.

  Thus, the graft copolymer composition (B) obtained can improve the demolding property of the metal mold | die in injection molding by mix | blending with an olefin type thermoplastic elastomer (A). As a method of injection molding, a method of molding using a commonly used thermoplastic resin injection molding machine can be used.

  The melt mixing temperature (cylinder temperature) in the injection molding is about 120 to 250 ° C. (especially 150 to 220 ° C.). If the temperature is too low, melting will be incomplete, melt viscosity will be high and mixing will be insufficient, and phase separation and delamination will easily occur. On the other hand, if it is too high, TPO and fatty acid amide are decomposed.

  The olefin-based thermoplastic elastomer (A) and the graft copolymer composition (B) may be kneaded stepwise, for example, using the above-described conventional extrusion kneading method or roll kneading method. After the master batch obtained by melt-kneading is pelletized, it may be mixed with TPO pellets in injection molding, supplied to an injection molding machine, and finally kneaded by an injection screw of the injection molding machine.

  The injection pressure in injection molding is, for example, about 40 to 100 MPa, and the injection speed may be, for example, about 0.3 to 3 m / min. The mold temperature is, for example, about 20 to 80 ° C, preferably about 20 to 60 ° C, and more preferably about 25 to 55 ° C (particularly about 30 to 50 ° C).

  The blending ratio of the graft copolymer composition (B) can be selected from a range of, for example, about 0.1 to 80 parts by weight with respect to 100 parts by weight of the olefin-based thermoplastic elastomer (A). -60 parts by weight, preferably 1-50 parts by weight, more preferably 2-40 parts by weight (particularly 3-35 parts by weight). If the proportion of the graft copolymer composition (B) is too small, the effect of the graft copolymer composition (B) will not be exhibited, and if it is too large, the rigidity and heat resistance of the molded product will be reduced.

  Furthermore, the ratio of the fatty acid amide (B2) is preferably in the range of, for example, about 0.01 to 10 parts by weight with respect to 100 parts by weight of the olefinic thermoplastic elastomer (A), more preferably 0.1. About 8 parts by weight. If the proportion of the fatty acid amide is too small, the effect of improving the demolding property is insufficient. Conversely, if the amount is too large, bleeding out of the fatty acid amide is likely to occur on the surface of the resulting molded product, and the appearance of the molded product is deteriorated. To do.

  For the olefin-based thermoplastic elastomer (A), in addition to the graft copolymer composition (B), as long as the properties of TPO are not impaired and the demoldability and oil resistance are not lowered, as necessary. , Conventional additives such as flame retardants (halogen-containing compounds such as halogenated styrene, phosphorus compounds, etc.), reinforcing fillers (inorganic fibers such as carbon fibers, particulate fillers such as mica and talc), stabilizers (phenols) -Based, thioether-based, phosphorus-based antioxidants, UV absorbers, light stabilizers, heat stabilizers, weathering agents, etc.), lubricants, dispersants, foaming agents, crosslinking agents, colorants, mineral oil-based softeners Etc. may be blended.

  The molded body obtained by such a method has less resistance when the air hose as a molded body is removed from the mold by the action of the graft copolymer composition (B) blended with TPO. The irreversible deformation of the molded body is prevented, and the demoldability from the mold is improved. Although the mechanism for improving the mold release property in the present invention is not necessarily clear, the improvement of the slipperiness of the surface of the molded product by the blending of the graft copolymer composition (B) is one of the factors that improve the mold release property. It is estimated that Furthermore, by adjusting the components of the propylene polymer and vinyl polymer in the graft copolymer (B1), not only can the surface be smoothened, but also both moderate rigidity and flexibility can be achieved. Even when air is blown into the mold, it is presumed that the diameter can be expanded smoothly, and even if the molded body comes into contact with the mold at the undercut portion, the molded body can be removed without being damaged.

  Furthermore, in this invention, the oil resistance of the shape | molded air hose improves by the effect | action of a graft copolymer composition (B). Regarding the improvement of oil resistance, in addition to the contribution of vinyl polymers (particularly nitrogen-containing vinyl monomers) which are branch segments of the graft copolymer, the surface of the molded product becomes smooth, It is presumed that the oil component hardly adheres to the surface also contributes.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, the demolding property and oil resistance of the hose manufactured by the Example and the comparative example were evaluated in accordance with the following method.

(Evaluation of demoldability)
When the air hose shown in FIG. 1 is formed by injection molding by the method described in Patent Document 1, and air is blown between the core mold of the part having the undercut portion and the air hose in FIG. The level of ease of demolding was qualitatively evaluated according to the following criteria.

○: Demolding is possible at a speed and light extraction force sufficient for mass production, and the molded product is not broken or stretched. △: If the extraction force is increased, it can be extracted at the prototype level. However, there is a case where elongation or tearing may occur in a part of the molded product that has been demolded. X: Level at which demolding cannot be performed, or when demolding, the air hose stretches or breaks and is difficult to demold.

(Evaluation of oil resistance)
The oil resistance of the air hose was evaluated by preparing a test sample having a thickness of 2 mm in a length and width of 8 cm by injection molding using the resin material used in each example and comparative example. The test method is as follows.

  First, the test sample was once immersed in engine oil (mineral oil) and then immediately pulled up, and the sample was hung for 20 seconds so that the oil on the sample surface freely dropped. Thereafter, the oil on the surface of the sample was wiped off, and the weight of the test sample was measured to evaluate the rate of change in weight before and after the test.

  That is, this evaluation result means that if the weight change rate is large, the oil absorption amount is large, and therefore, the swelling is severe and the oil resistance is poor. On the contrary, if the weight change rate is small, the oil absorption amount is small. It means that swelling is suppressed and oil resistance is excellent.

The weight change rate was calculated according to the following calculation formula, assuming that the sample weight before the test was W ₀ and the sample weight after the test was W ₁ .

Weight change rate = (W ₁ −W ₀ ) / W ₀ × 100 (%).

Example 1
A graft copolymer composition (composition a) 5 prepared by the following method with respect to 100 parts by weight of an olefin-based thermoplastic elastomer (TPO: manufactured by AES Co., Ltd., trade name “Santoprene”) 5 The parts by weight were kneaded with an extruder and pelletized. Further, the obtained pellets were supplied to an injection molding machine, and an automobile air hose having a bend shape and a bellows portion shown in FIG. 1 was injection molded. The main dimensions of the air hose are a total length of 250 mm, an inner diameter of 65 mm, a bellows thickness of 1.5 mm, a non-bellows thickness of 3 mm, and a bellows height of 8 mm.

(Preparation of graft copolymer composition)
In a 5 liter stainless steel autoclave, 2500 g of pure water was added, and 2.5 g of polyvinyl alcohol was dissolved as a suspending agent. Furthermore, 700 g of particulate isotactic polypropylene (manufactured by Sun Allomer Co., Ltd., trade name “PM Series”) was added to the autoclave, and the mixture was stirred and dispersed.

  Separately, 1.5 g of di-3,5,5-trimethylhexanoyl peroxide as a radical polymerization initiator, 9 g of t-butylperoxymethacryloyloxyethyl carbonate as a radical polymerizable organic peroxide, 200 g of styrene and nitrogen It was dissolved in a mixed solution with 100 g of acryloylmorpholine as a vinyl monomer. This solution was put into the autoclave and stirred.

  Next, the autoclave was heated to 60 to 65 ° C. and stirred for 3 hours to impregnate isotactic polypropylene with a radical polymerization initiator, a radical polymerizable organic peroxide and a vinyl monomer. Subsequently, after confirming that the impregnation ratio of the total amount of the impregnated vinyl monomer, radical polymerizable organic peroxide and radical polymerization initiator is 30% by weight or more of the addition amount, the temperature is changed. The temperature was raised to 70 to 75 ° C. and maintained at that temperature for 6 hours to complete the polymerization, washed with water and dried to obtain a grafted precursor.

  Furthermore, this grafting precursor was extruded at 180 ° C. with a Laboplast mill single screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and grafted to obtain a graft copolymer (1). When this graft copolymer (1) was observed with a scanning electron microscope (manufactured by Hitachi, Ltd.), a multiphase structure type heat in which a true spherical resin having a particle size of 0.3 to 0.4 μm was uniformly dispersed. It was a plastic resin.

  80 parts by weight of the obtained graft copolymer (1) was dry blended with 20 parts by weight of oleic amide, and kneaded with a coaxial twin screw extruder with a screw diameter of 30 mm set at a cylinder temperature of 180 ° C. A pellet of the graft copolymer composition (Composition A) was obtained.

(Example 2)
An automotive air hose was produced by injection molding in the same manner as in Example 1 except that the amount of the graft copolymer composition (composition a) was changed to 10 parts by weight.

(Example 3)
The air hose for automobiles was produced by injection molding in the same manner as in Example 1 except that the amount of the graft copolymer composition (composition a) was changed to 30 parts by weight.

Example 4
In the preparation of the graft copolymer composition, a block type propylene-ethylene copolymer was used instead of isotactic polypropylene, and acrylonitrile was used instead of acryloylmorpholine. After preparing the graft copolymer composition (composition b), it was produced by injection molding of an automotive air hose in the same manner as in Example 1.

(Example 5)
In the preparation of the graft copolymer composition, a graft copolymer composition (composition c) was prepared in the same manner as in Example 1 except that acrylonitrile was used instead of acryloylmorpholine. Similarly, an air hose for automobiles was produced by injection molding.

(Comparative Example 1)
An automotive air hose was injection-molded and produced in the same manner as in Example 1 except that the olefin-based thermoplastic elastomer was used alone without blending the graft copolymer composition.

(Comparative Example 2)
In place of the graft copolymer composition (a), for automobiles, in the same manner as in Example 1, except that 20 parts by weight of a silicone-based modifier (trade name “ML-350” manufactured by Hexa Chemical Co., Ltd.) is used. An air hose was manufactured by injection molding.

  Table 1 shows the composition and evaluation results of each Example and Comparative Example.

  As is apparent from Table 1, in the examples, the moldability of the molded air hose can be reduced by blending a specific graft copolymer composition with an olefin-based thermoplastic elastomer used for injection molding of the air hose. Improved.

  On the other hand, in the comparative example, the demolding property is low. In particular, in Comparative Example 2 aiming at the effect of improving the demoldability by improving the slipperiness with the silicone-based modifier, a large amount of the silicone-based modifier is blended so as to partially bleed on the surface of the molded product. Nevertheless, the remarkable demolding improvement effect as in the example was not obtained. The reason for this is presumed that the duct is easily deformed or broken during the demolding operation due to a decrease in duct strength due to the addition of the silicone-based modifier.

  In the examples, it was confirmed that the change in the weight of the duct material was reduced in the oil resistance evaluation test, and the duct material absorbed the engine oil and swelled even when the engine oil was applied to the air duct. And the oil resistance of the air hose is improved.

  The present invention is manufactured by injection molding and has an undercut portion, for example, an air hose or a vehicle (for example, a transportation vehicle such as an automobile) attached to various electric appliances (for example, a vacuum cleaner or an air conditioner). In particular, the present invention can be effectively used for an automotive air hose that is a part of a duct for supplying air to an internal combustion engine of an automobile.

DESCRIPTION OF SYMBOLS 1 ... Automotive air hose 2 ... Bellows part 3a, 3b ... Non-bellows part 4a, 4b ... Reinforcement rib 10 ... Injection mold 11 ... Cavity mold 12 ... Core mold 13 ... Contact surface 14 ... Cavity

Claims (4)

A graft copolymer (B1) formed of a backbone segment composed of a propylene polymer and a branch segment composed of a nitrogen-containing vinyl polymer, and a fatty acid amide for the olefin thermoplastic elastomer (A) (B2) and the graft copolymer composition (B) by injection molding by blending, demolding to flexion portion and / or oil resistance and the core mold of the air hose for a motor vehicle having an undercut portion including A method of improving
The ratio (weight ratio) between the graft copolymer (B1) and the fatty acid amide (B2) is the former / the latter = 50/50 to 99/1, and the graft copolymer composition (B) is treated with olefinic heat. The method of mix | blending 1-50 weight part with respect to 100 weight part of plastic elastomers (A) .   The method according to claim 1, wherein the graft copolymer (B1) is formed of a continuous phase and a dispersed phase dispersed in a granular form in the continuous phase, and the average particle size of the dispersed phase is 0.001 to 10 µm.   The graft copolymer (B1) is formed of a trunk segment composed of a propylene-based block copolymer and a branch segment composed of a nitrogen-containing vinyl polymer, and the fatty acid amide (B2) has 10 to 25 carbon atoms. The method according to claim 1 or 2, which is a fatty acid amide. An air hose for automobiles composed of an olefinic thermoplastic elastomer (A) and a graft copolymer composition (B) and having a bent part and / or an undercut part ,
The graft copolymer composition (B) comprises a graft copolymer (B1) formed of a trunk segment composed of a propylene polymer and a branch segment composed of a nitrogen-containing vinyl polymer and a fatty acid amide ( B2) and only it contains,
The proportion of the graft copolymer composition (B) is 1 to 50 parts by weight with respect to 100 parts by weight of the olefin-based thermoplastic elastomer (A), and
An automotive air hose in which the ratio (weight ratio) between the graft copolymer (B1) and the fatty acid amide (B2) is the former / the latter = 50/50 to 99/1 .

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