JPH0564662B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a polyolefin-based soft resin composition. BACKGROUND ART Conventionally, polyurethane and polypropylene materials have been mainly used for large molded products such as plastic bumpers for automobiles. However, it has been pointed out that the former is expensive, has poor weather resistance, and has a poor yield during production. On the other hand, the latter contains a large amount of rubber components to improve low-temperature impact resistance and flexibility, which causes problems such as the molded product surface being easily scratched and the occurrence of sink marks peculiar to polypropylene. Ta. Olefin thermoplastic elastomers are attracting attention as a solution to both of these problems. As an olefin thermoplastic elastomer,
For example, a composition consisting of a polyolefin and a partially crosslinked rubber (Japanese Patent Publication No. 54-23702), or a composition in which a polyolefin and a rubber component are combined in the presence of an organic peroxide to improve the fluidity of this composition. Partially crosslinked composition in which polyolefin is added to the treated composition (Japanese Patent Publication No. 15743/1983)
Alternatively, a method for producing a composition (Japanese Patent Publication No. 15740/1983) has been proposed. Problems to be Solved by the Invention However, the organic peroxide used as a crosslinking agent used in the production of the above partially crosslinked thermoplastic elastomer composition has strong reactivity, and therefore it is necessary to adjust the degree of crosslinking to an appropriate level. Because molecular chain scission occurs simultaneously with crosslinking, the physical properties of the composition may deteriorate, the low molecular weight substances produced may have an adverse effect on paintability, and partial gelation may cause the surface of the molded product to become rough. There remained the issue of accompanying.
Furthermore, there was a problem in that free radicals caused by the organic peroxide remained in the molded product, impairing thermal stability. The inventors of the present invention have conducted studies to solve the above-mentioned problems, and as a result, they have found that halogenated butyl rubber is blended into the rubber component and reacted with metal oxide and/or metal chloride as a crosslinking agent. As a result, a composition was obtained consisting of a polyolefin having a mesh structure due to selective crosslinking of halogenated butyl rubber without molecular chain scission, and a partially crosslinked rubber component. However, although this composition has excellent performance as a thermoplastic elastomer, there remains room for improvement in fluidity in molding large molded products and in paintability of molded products. The present invention has mechanical properties suitable for large molded products without impairing rubber elasticity, especially impact resistance and surface scratch resistance, and has good paintability and fluidity, and does not cause flow marks or sink marks during molding. It is an object of the present invention to provide an olefin-based soft resin composition that can produce molded products that do not generate molded products. Means for Solving the Problems As a result of intensive research, the present inventors have blended halogenated butyl rubber and further modified polyolefin into the rubber component, and reacted with metal oxide and/or metal chloride as a crosslinking agent. The present invention was completed based on the discovery that the object of the present invention can be achieved by further blending a polyolefin into a composition consisting of a polyolefin and a partially crosslinked rubber component. That is, the present invention provides (A) polypropylene 10 to 90
parts by weight, (B) 90 to 10 parts by weight of halogenated butyl rubber (however, (A) + (B) = 100 parts by weight), (C) 10 to 120 parts by weight of olefin rubber, (D) mineral oil softener 5 A mixture consisting of ~120 parts by weight and (E) 1 to 90 parts by weight of a modified polyolefin added by reacting an unsaturated carboxylic acid or its derivative is mixed with (F) a metal oxide and/or
Alternatively, the gist is an olefin-based soft resin composition which is heated and melted and kneaded in the presence of a metal chloride, and then 20 to 200 parts by weight of polyolefin (G) is uniformly blended into 100 parts by weight of the material to be kneaded. However, the above-mentioned composition of the present invention also includes a case where part or all of the component (E) is blended into the material to be kneaded. Composition material (A) Polypropylene Main component is propylene homopolymer or propylene copolymerized with α-olefin such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, etc. It is a copolymer.
Here, the copolymer includes random or block type copolymers. In addition, the melt flow rate (hereinafter
MFR) is 0.3 to 60 g/10 minutes, preferably 1 to 40 g/10 minutes, and more preferably 3 to 30 g/10 minutes.
(hereinafter referred to as component A). Component A has the highest melting point among polyolefins and contributes to improving heat resistance and mechanical strength. (B) Halogenated butyl rubber means halogenated isobutylene-isoprene copolymer rubber (hereinafter referred to as component B). Examples of halogen include chlorine or bromine atoms. The halogen content is usually 0.5-4.0% by weight. or,
Component B preferably has a Mooney viscosity of 30 to 100 at ML1+8, 100°C, and an unsaturation degree of 0.5 to 4.0 mol%. Component B is a rubber that can be crosslinked with metal oxides and metal chlorides, and is dispersed in the composition as a crosslinked rubber to form a mesh structure, and has scratch resistance, heat resistance, oil resistance, vibration breathability, and gas impermeability. , imparts slip resistance, etc. (C) Olefin rubber Monoolefin copolymer rubber of two or more monoolefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene (typically ethylene - propylene copolymer rubber), and two of the above monoolefins (ethylene and propylene are preferred) and non-conjugated diolefins or butadienes such as dicyclopentadiene, 1,4-hexadiene, cyclooctandiene, methylene norbornene, ethylidene norbornene, Includes copolymer rubbers with conjugated diolefins such as isoprene. Also, the C component is ML ₁₊₈ ,
127 DEG C., a Mooney viscosity of 5 to 300, an iodination of up to 30, and an ethylene content of 35 to 85% by weight are preferred. In addition, polyisobutylene, butyl rubber, etc. are also included (hereinafter referred to as component C). Component C exists in the composition as a non-crosslinked rubber, provides flexibility and molding fluidity, and acts as a binder at the phase interface between component A and component B, thereby improving tensile strength and elongation. (D) Mineral oil softener A high boiling point petroleum fraction used to reduce the hardness of vulcanized rubber and increase its flexibility and elasticity.
Examples include paraffin type, naphthenic type, and aromatic type (hereinafter referred to as component D). Note that aromatic components among component D are not preferred for use in materials to be coated because they have an adverse effect on coating properties. (E) Modified polyolefin Examples include polyolefins added by reacting unsaturated carboxylic acids or derivatives thereof (hereinafter referred to as component E). Examples of polyolefins include homopolymers of α-olefins such as ethylene or propylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene, copolymers of ethylene and α-olefins, or copolymers of these α-olefins. Examples include copolymers of two or more olefins. Among the above polyolefins, low density polyethylene, linear low density polyethylene, medium and high density polyethylene, polypropylene, propylene-ethylene random or block copolymers and the like are preferred. In addition, as unsaturated carboxylic acids, maleic acid,
Examples include endo-bicyclo-[2,2,1]-5-heptene-2,3-dicarboxylic acid, itaconic acid, fumaric acid, acrylic acid, methacrylic acid, and derivatives thereof include acid anhydrides, acid Examples include amides and esters. Various known methods can be used to react the polyolefin with an unsaturated carboxylic acid or a derivative thereof. For example, it can be obtained by adding a reaction initiator such as an organic peroxide to a polyolefin and an unsaturated carboxylic acid or a derivative thereof, mixing them in advance, and then melt-kneading them. Here, the amount of the unsaturated carboxylic acid or its derivative added to the polyolefin is preferably 0.02 to 2% by weight. In addition, the above E component includes an olefin copolymer rubber (Mooney viscosity ML ₁₊₈
127℃5~300, iodine value up to 30, ethylene content 35~
Olefin rubber such as polyisobutylene (density 0.91 to 0.93 g/cc, molecular weight (according to the Staudinger method) of about 60,000 to 200,000) may also be included. When reacting an unsaturated carboxylic acid or its derivative with a mixture of polyolefin and olefin rubber, the mixing ratio is 10 to 90% by weight of polyolefin and 90 to 10% by weight of olefin rubber, and the amount of acid added is 0.02 to 90% by weight.
The content is preferably 2% by weight. Component E not only improves fluidity but also enhances the role of a binder in compatibility of each component in the composition, and improves mechanical strength, especially impact resistance. (F) Metal oxide, metal chloride (crosslinking agent) Examples of the metal oxide include zinc chloride, magnesium oxide, lead oxide, calcium oxide, etc., and zinc oxide is preferable. Examples of metal chlorides include zinc chloride and tin chloride. Further, in order to prevent corrosion of the mold etc. due to free halogen, it is desirable to use magnesium oxide as a scavenger (hereinafter referred to as component F). The usage amount of F component is A component, B component, C component,
It is preferably 0.2 to 10 parts by weight, more preferably 1 to 5 parts by weight per 100 parts by weight of components D and E. (G) Polyolefin A homopolymer of α-olefin such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, or a copolymer of ethylene and α-olefin, or a copolymer of these α-olefins.
Copolymers of two or more types of -olefins, copolymers of ethylene or vinyl esters containing these α-olefins as main components, unsaturated carboxylic acids, or derivatives thereof, etc. can be mentioned. Here, the copolymer includes random or block copolymers. These polyolefins
MFR (190℃, however, 230℃ for propylene polymer)
is preferably 0.1 to 20 g/10 minutes for ethylene polymers, and 15 to 60 g/10 minutes for propylene polymers. Moreover, two or more types of these polyolefins can be used in combination. Among the above polyolefins, low-density polyethylene, linear low-density polyethylene, medium-density or high-density polyethylene, polypropylene, or random or block copolymers containing propylene as a main component are preferred. Further, an olefin-based elastomer such as ethylene-propylene rubber, ethylene-propylene-diene copolymer rubber, etc. can be mixed with the above-mentioned polyolefin. In the composition obtained according to the present invention, component G improves fluidity and paintability without impairing rubber elasticity. In addition, since component G has the same function as component A, it can be blended with component A in a mutually complementary manner. However, the effect of blending component G can only be obtained by blending it into a composition in which the above-mentioned halogenated butyl rubber is partially crosslinked, and even if it is blended into a composition in other combinations, such effects will not be obtained. I can't get it. In addition to the above-mentioned components, antioxidants, ultraviolet absorbers, stabilizers such as metal deterioration inhibitors, lubricants, antistatic agents, electrical property improvers, flame retardants, processability improvers, Additives such as pigments, talc,
Inorganic fillers such as calcium carbonate, barium sulfate, mica, and calcium silicate can be blended. Blending proportions The blending proportions of component A, B component, C component, D component, and E component in the present invention are 10 to 90 parts by weight of component A, preferably 20 to 70 parts by weight, and 10 to 90 parts by weight of component B. 30 to 80 parts by weight (A component + B
Component = 100 parts by weight), C component 10~
120 parts by weight, preferably 10 to 100 parts by weight, component D 5
~120 parts by weight, preferably 5 to 100 parts by weight and E
The amount of the component is 1 to 90 parts by weight, preferably 5 to 50 parts by weight. In addition, the F component (crosslinking agent) is the above-mentioned A to E components.
It is preferably 0.2 to 10 parts by weight, more preferably 1 to 5 parts by weight per 100 parts by weight. If the amount of component A is less than 10 parts by weight, mechanical strength and heat resistance will be poor. On the other hand, if the amount of component A exceeds 90 parts by weight, the hardness and compression set will be large and the elastomeric properties will be impaired. Furthermore, if the C component is less than 10 parts by weight, the flexibility will be low and the molding fluidity will be poor. Moreover, the compatibility between component A and component B becomes poor. On the other hand, if the C component exceeds 120 parts by weight, the mechanical strength will decrease and the compression set will increase, which is not preferable. Furthermore, if the amount of component D is less than 5 parts by weight, the flexibility will be insufficient, while if it exceeds 120 parts by weight, the mechanical strength will decrease and the product will become sticky, which is undesirable. Furthermore, if the amount of component E is less than 1 part by weight, the compatibility of each component will be insufficient and mechanical strength, especially impact resistance and fluidity, will not improve. On the other hand, if it exceeds 90 parts by weight, no further effect can be expected and it is uneconomical. The amount of component G added to the material to be kneaded in the presence of component F (crosslinking agent) is 20 to 200 parts by weight, more preferably 40 to 70 parts by weight, based on 100 parts by weight of the material to be kneaded. If the amount of component G is less than 20 parts by weight, the improvement in fluidity and paintability will be insufficient, while if it exceeds 200 parts by weight, the flexibility and rubbery properties of the resulting composition will be impaired, which is not preferable. Method for producing composition The composition of the present invention is prepared by first adding component A, component B, component C, component D, component E, and a crosslinking agent (metal oxide and/or metal chloride), and further other components as necessary. are heated and melted and kneaded. Kneading is carried out at a temperature where each component melts, usually 160-250℃,
Preferably at 170-220℃ for 1-10 minutes, preferably 3
It should be done for ~5 minutes. By doing so, it is possible to produce a composition to be kneaded in which only the dispersed component B is selectively crosslinked. Melt kneading is carried out using a commonly used pressure kneader, Banbury mixer, screw extruder, or the like. (First step) Next, the composition to be kneaded obtained above and the G component are uniformly blended. A method for uniformly blending the composition to be kneaded and the G component is to premix both pellets using a Henschel mixer, a ribbon blender, etc., and then extrude them using a Banbury mixer.
Examples include a method of melting and kneading using a pressure kneader or the like. At this time, various stabilizers, colorants, and inorganic fillers may be added as necessary. (Second Step) In the production of the above composition, component E can be blended in the first step, the second step, or both steps. Effects of the Invention In the composition of the present invention, component B is partially crosslinked, so it has excellent compatibility, high mechanical strength without impairing rubber properties, and improved surface scratch resistance. be. In addition, the blending of modified polyolefin increases the affinity of each component and improves impact resistance. Furthermore, since the uniform blending of the G component provides good paintability and fluidity, large-sized molded products with good appearance without flow marks or sink marks can be obtained. In addition, the crosslinking agent used during the production of the composition is
It is safer than organic peroxides and is thermally stable, so the degree of crosslinking can be adjusted as desired. Therefore,
There is no cutting of the polypropylene molecular chain, no lowering of the molecular weight, and no deterioration of the coating properties or physical properties of the composition. Furthermore, there are no residual free radicals caused by organic peroxides, and the heat resistance is good. In addition, despite the above improvements, it is less expensive than polyurethane products and can have mechanical properties and a high-class appearance similar to those of large polyurethane molded products. The composition of the present invention can be easily molded by conventional thermoplastic resin molding methods, such as blow molding, extrusion molding, and injection molding. The composition of the present invention has an excellent balance of flexibility, strength, and heat resistance, and has good moldability, so it can be used particularly as a material for automobile parts, such as rack/pinion boots, hoses, side moldings, spoilers, and bumpers. Are suitable. Examples Hereinafter, the present invention will be explained in detail by examples.
In addition, parts and percentages in the examples are based on weight, and the test method is as follows. (1) MFR: JIS K 7210 (load 2.16Kg, 230℃) (2) MI: JIS K 7210 (load 2.16Kg, 190℃) (3) Tensile strength at break, tensile elongation at break: JISK 7113 (4) Bending elasticity Rate: JIS K 7203 (5) Izot impact strength: JIS K 7110 (6) Shore hardness: JIS K 7215 (D method) (7) Heat distortion temperature test: JIS K 7207 (8) Formability: Injection molding conditions Molding machine ^Made by Mitsubishi Natco ³⁵⁰ MV Flow mark 〇: Not occurring △: Very slightly occurring ×: Significantly and frequently occurring sink marks 〇: Not occurring △: Very slightly occurring ×: Significantly occurring often Gloss Measured on a 60° mirror surface using the JIS K7150 method . 〇: Gloss retention rate 30% or more △:〃 10-30% Manufactured by Chemical Co., Ltd.
RB-291 (trade name)] and baked at 80°C for 30 minutes. Next, a top coat [Flexen-101 (trade name), manufactured by Nippon Paint Co., Ltd.] was applied thereon and baked at 120°C for 30 minutes. Plasma method After cleaning the test piece with trichloroethane vapor for 1 minute, it was subjected to plasma treatment (argon plasma,
1.0 ^kW × 1.0 ^torr × 60 seconds), apply top paint [Nippon Paint Co., Ltd., Flexene-101 (product name)], and
Bake for 30 minutes at °C. Initial adhesion evaluation: Based on JIS K 5400 cross-cut test. Hot water resistance: After 240 hours of immersion in 40℃ hot water, appearance and burlap test. Examples 1 to 16, Comparative Examples 1 and 2 Materials used Component A: Propylene-ethylene block copolymer (MFR 3.0 g/10 min, ethylene content 7
%, hereinafter referred to as PP block-1). Component B: Chlorinated isoptylene-isoprene copolymer rubber (Mooney viscosity ML ₁₊₈ 100℃50,
Chlorine content 1%, degree of unsaturation 2 mol%, hereinafter C
(referred to as IIR). Component C: Ethylene-propylene-ethylidene norbornene copolymer rubber (Mooney viscosity
ML ₁₊₈ 127℃230, iodine value 18, ethylene content 60%, hereinafter referred to as EPDM-1). Component D: naphthenic process oil (viscosity-specific gravity constant 0.880, hereinafter referred to as a softener). Component E: Maleic anhydride modified product of propylene-ethylene block copolymer (acid addition amount 0.5
%, hereinafter referred to as CMPP), maleic anhydride modified product of high density polyethylene (acid addition amount
0.5%, hereinafter referred to as CMHDPE), maleic anhydride modified product of low density polyethylene (acid addition amount 0.5%, hereinafter referred to as CMLDPE), maleic anhydride modified product of ethylene-propylene rubber (acid addition amount 0.3%, hereinafter referred to as CMEPR) . F component: zinc oxide, magnesium oxide (halogen scavenger). G component: Propylene-ethylene block copolymer (MFR40g/10min, ethylene content 7%,
(hereinafter referred to as PP block-2), high density polyethylene (density 0.945g/cm ³ , MI 0.35g/
10 minutes, hereinafter referred to as HDPE), ethylene-propylene-ethylidenenorbonene copolymer rubber (Mooney viscosity ML ₁₊₈ 127℃45, iodine value 3, ethylene content 65%, hereinafter EPDM)
-2), ethylene-propylene rubber (Mooney viscosity ML ₁₊₄ 100°C24, ethylene content 73%, hereinafter referred to as EPR). Other parts: Talc (average particle size 2.5μ). Manufacture of the composition The above components except component G are blended in the proportions shown in Table 1, and 2 parts by weight of zinc oxide and 0.5 parts by weight of magnesium oxide are blended with 100 parts by weight of each mixture. 170℃ in a mixer,
After melt-kneading for 3 minutes, the mixture was cut into sheets and pelletized. (First step) Next, component G and other components were blended into each pellet obtained in the first step in the proportions shown in Table 1, premixed using a Henschel mixer, and then transferred to a twin screw extruder. The composition was supplied and extruded at 200°C to obtain the desired composition (second step). The characteristics of each composition are shown in Table 1.

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【table】

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Claims (1)

[Claims] 1 (A) 10 to 90 parts by weight of polypropylene, (B) 90 to 10 parts by weight of halogenated butyl rubber (however, (A) + (B) = 100 parts by weight)
(parts by weight), (C) 10 to 120 parts by weight of olefin rubber, (D)
A mixture consisting of 5 to 120 parts by weight of a mineral oil softener and (E) 1 to 90 parts by weight of a modified polyolefin added by reacting with an unsaturated carboxylic acid or its derivative is mixed with (F) a metal oxide and/or metal chloride. The material to be kneaded is heated and melted and kneaded in the presence of the material to be kneaded.
An olefin-based soft resin composition prepared by uniformly blending 20 to 200 parts by weight of (G) polyolefin to 100 parts by weight.