JP2017105972A - Polypropylene resin composition for corrugate tube and molded article manufactured by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene resin composition for a corrugate tube for automobile which can be used in an engine room or a bottom side of automobiles where they are not used conventionally by improving long term thermal stability of a polypropylene-based corrugate tube.SOLUTION: There is provided a polypropylene resin composition for corrugate tube containing 100 pts.wt. of a polypropylene resin, 1 to 30 pts.wt. of a flame retardant, 0.1 to 5 pts.wt. of a flame retardant assistant and 0.15 to 15 pts.wt. of an antioxidant, in which the antioxidant is a mixture of 3 or more kinds of antioxidant selected from a phenolic antioxidant, an aromatic amine-based antioxidant, a phosphor-based antioxidant and a sulfur-based antioxidant.SELECTED DRAWING: None

Description

  The present invention relates to a polypropylene resin composition for corrugated tubes for automobiles, and more specifically, it can improve the long-term thermal stability of polypropylene corrugated tubes, and can also be used in the engine room and the bottom side of automobiles that could not be used conventionally. The present invention relates to a polypropylene resin composition for an automobile corrugated tube which can be used.

  Corrugated tubes for automobiles can be divided into polypropylene and nylon from the side of the material. Nylon corrugated tubes are used in the engine room and the bottom of automobiles, and polypropylene corrugated tubes are used for applications that do not require long-term heat resistance.

  Existing polypropylene corrugated tubes are mainly non-flame retardant or flame retardant polypropylene. Non-flame retardant polypropylene is used for indoor use where there is almost no thermal influence. However, flame retardant polypropylene is affected by heat, and therefore requires flame resistance of UL V-2 level. As a related art related to this, the contents relating to the flame-retardant polypropylene resin composition are disclosed in Korean Patent No. 10-0796730. However, there is no purpose to improve the long-term thermal stability of the flame retardant polypropylene resin composition.

  Recently, attempts have been made to apply flame retardant polypropylene corrugated tubes for nylon corrugated tubes. At this time, an important technical problem is that long-term heat resistance close to the nylon level is required.

  The present invention is applied to a flame-retardant polypropylene-based corrugated tube, and has long-term thermal safety and is used on the bottom side of an engine room or an automobile.

Republic of Korea Registered Patent No. 10-0796730

  The objective of this invention is providing the polypropylene resin composition for corrugated tubes which can improve the long-term thermal stability of the existing polypropylene corrugated tube for motor vehicles, and can be used for the engine room or the bottom side of a motor vehicle.

  In order to achieve the object of the present invention, the present invention provides 1 to 30 parts by weight of a flame retardant, 0.1 to 7 parts by weight of a flame retardant aid and 0 to 0 parts by weight of 100 parts by weight of polypropylene resin. 15 to 15 parts by weight, and the antioxidant is at least three or more selected from the group consisting of phenolic antioxidants, aromatic amine antioxidants, phosphorus antioxidants and sulfur antioxidants A polypropylene resin composition for corrugated tubes, which is a mixture of antioxidants, is provided.

  Despite being a polypropylene resin composition, the polypropylene resin composition according to the present invention has high long-term thermal stability and can be used for engine rooms and automobile flooring, reducing the weight of automobiles, corrugated tube processing There is an advantage that energy and material costs can be saved.

  Nylon corrugated tubes were used in existing car engine rooms and car floor corrugated tubes. However, if nylon corrugated tubes are replaced with polypropylene corrugated tubes with excellent long-term heat resistance, the material costs for automobile production As a result, the weight of the vehicle can be reduced, and the energy cost when processing the corrugated tube can be reduced.

  Hereinafter, the present invention will be described in more detail. Hereinafter, preferred embodiments of the present invention and physical properties of each component will be described in detail. This is to explain in detail to the extent that a person having ordinary knowledge in the technical field to which the present invention belongs can easily carry out the invention. However, this does not mean that the technical idea and category of the present invention are limited.

  According to one embodiment of the present invention, 1 to 30 parts by weight of flame retardant, 0.1 to 7 parts by weight of flame retardant aid, and 0.15 to 15 parts of antioxidant for 100 parts by weight of polypropylene resin. Containing at least 3 parts by weight of the antioxidant, wherein the antioxidant is selected from the group consisting of a phenolic antioxidant, an aromatic amine antioxidant, a phosphorus antioxidant and a sulfur antioxidant. A polypropylene resin composition for corrugated tubes, which is a mixture, is provided.

<Polypropylene resin>
According to an embodiment of the present invention, the polypropylene resin is preferably block copolypropylene, and may further include homopolypropylene or random polypropylene. The block copolypropylene described above is mainly composed of propylene, and may further contain monomers such as ethylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene as auxiliary components. Specifically, the block copolypropylene described above contains 1 to 13% by weight of ethylene (B—C2) bonded in the chain with propylene as a main component. It is preferred to further include an alpha olefin such as methyl-1-pentene. The melt index of the block copolypropylene is preferably 0.1 to 3 g / 10 min (ASTM D1238, 2.16 kg, 230) in the ASTM standard D1238 test method.

  If the melt index is less than 0.1 g / 10 min, the extrudability of the corrugated tube is lowered, and if it exceeds 3 g / 10 min, an elongation rate suitable for the corrugated tube is not obtained.

  Moreover, the polypropylene suitable for the corrugated tube for motor vehicles of this invention fits the polypropylene resin whose elongation rate is 300% or more.

  The polypropylene resin composition suitable for the corrugated tube of the present invention preferably has an elongation retention of 30% or more when left in an oven at 150 ° C. for 70 days. If the elongation retention is less than 30%, long-term heat resistance is insufficient.

<Flame retardant>
According to one embodiment of the present invention, the type of the flame retardant is not particularly limited as long as the flame retardant has UL94V-2 grade flame retardancy.

  According to one embodiment of the present invention, it can be used preferably selected from halogen flame retardant, hydrous inorganic compound flame retardant and phosphorus flame retardant.

  Examples of halogen flame retardants include tetrabromobisphenol A, hexabromocyclododecane, decabromodiphenyl ether, dodecachloro-dodecahydromethanodibenzocyclooctene, bis (pentabromophenyl) ethane, tetrabromobisphenol A flame retardant, tetrabromobisphenol S. And flame retardants.

  Examples of the hydrous inorganic compound flame retardant include magnesium hydroxide, aluminum hydroxide, hydrotalcite and the like.

  Examples of the phosphorus flame retardant include triaryl phosphate, alkyl diaryl phosphate, trialkyl phosphate, resorcinol bisdiphenyl phosphate, and the like.

  As for content of the flame retardant mentioned above by this invention, 1-30 weight part of flame retardants with respect to 100 weight part of polypropylene resins are desirable. If the flame retardant content exceeds 30 parts by weight, the moldability is not good, and if the flame retardant content is less than 1 part by weight, sufficient flame retardancy cannot be obtained.

<Flame retardant aid>
According to an embodiment of the present invention, the flame retardant aid may be used by selecting one or more of antimony trioxide, antimony pentoxide, and boron compounds.

  The content of the flame retardant aid may include 0.1 to 7 parts by weight of the flame retardant aid with respect to 100 parts by weight of the polypropylene resin. Flame retardant aids exhibit a flame retardant synergistic effect when used in combination with flame retardants. However, even if the content of the flame retardant auxiliary exceeds 7 parts by weight, the flame retardancy does not increase any more. When the content of the flame retardant aid is less than 0.1 parts by weight, it is difficult to obtain sufficient flame retardancy.

<Antioxidant>
According to an embodiment of the present invention, it is preferable to use a mixture of at least three types of antioxidants rather than using only one type, and particularly phenolic antioxidants, aromatic amine antioxidants, It is preferable to use a mixture of at least three or more antioxidants selected from the group consisting of phosphorus-based antioxidants and sulfur-based antioxidants.

  The polymer chain undergoes oxidative degradation through an auto-oxidation process. That is, radicals are formed on the polymer chain by reaction with heat, light, mechanical stress, and residual catalyst / impurities. Of the three antioxidants, the primary antioxidant plays a role in scavenging the radicals thus generated. Radicals not captured by the primary antioxidant react with oxygen to form peroxide radicals. Peroxide radicals react with hydrocarbons to form peroxides.

  The peroxide thus generated is converted into alcohol and ketone by the secondary antioxidant among the three or more kinds of antioxidants, and the decomposition process of the polymer chain is interrupted. The secondary antioxidant exhibits a better effect when used in combination with the primary antioxidant than when used alone.

  Among the three or more antioxidants, the tertiary antioxidant is preferably an antioxidant having long-term heat resistance, and such a long-term heat-resistant antioxidant is a peroxide such as the secondary antioxidant. Is converted to alcohol and ketone to prevent oxidation of the polymer chain. However, the secondary antioxidant plays a role of preventing oxidation at a temperature of 170 ° C. or higher, whereas the long-term heat-resistant antioxidant plays a role of preventing the polymer chain from being oxidized at a temperature of 150 ° C. or lower.

  The total content of the three or more antioxidants is preferably 0.15 to 15 parts by weight with respect to 100 parts by weight of the polypropylene resin.

  If the total content of antioxidants is less than 0.15 parts by weight, the long-term heat resistance is lowered, and if it exceeds 15 parts by weight, yellowing may occur.

  The antioxidant mixture comprises a phenolic antioxidant or an aromatic amine antioxidant as a primary antioxidant, a phosphorus antioxidant as a secondary antioxidant, and a sulfur antioxidant as a tertiary oxidation. Used as an antioxidant, 0.1-5 parts by weight of the primary antioxidant, 0.05-5 parts by weight of the secondary antioxidant, 0.1-5 parts by weight of the tertiary antioxidant It is preferable to include.

  More preferably, the content of the primary antioxidant is 0.1 to 3 parts by weight.

  If the content of the primary antioxidant is less than 0.1 parts by weight, the long-term heat resistance intended in the present invention cannot be ensured. When the content of the primary antioxidant exceeds 5 parts by weight, yellowing tends to occur under conditions where NOx exists.

  A hindered phenol type can be applied as the phenolic antioxidant. That is, for example, 2,6-2,6-di-tert-4-butylphenol (BHT), thioethylene bis [2- (3,5-di-tert-4-butylphenyl) propionate (for example, SONGWON) Songnox 1035), octadecyl-3- (3,5-di-tert-4-butyl-4-phenyl) propionate (for example, Songox 1076 by SONGWON), tetrakis [methylene-3- (3,5-di- tert-butyl-4-hydroxyphenyl) propionate] methane (for example, Songox 1010 manufactured by SONGWON) It can be selected and used above.

  Examples of the aromatic amine antioxidant include phenylnaphthylamine, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine, and N, N′-di-2-naphthyl-p-phenylenediamine, 4,4 ′. -From the group consisting of dioctyldiphenylamine, N, N'-diphenyl-P-phenylenediamine, N-phenyl-N'-cyclohexyl-P-phenyleneamine, N, N'-di-O-tri-ethylenediamine, alkylated diphenylamine One or more selected can be used.

  In the present invention, a phosphorus-based antioxidant is used as the secondary antioxidant, and examples thereof include tris (2,4-di-tert-butylphenyl) phosphite (for example, Songnox 1680 manufactured by SONGWON), Tris (nonylphenyl). Examples thereof include phosphite (TNPP), Di- (2,4-di-t-butylphenyl) pentaerythritol diphosphite, and the like. As phosphorus antioxidants, tris (2,4-di-tert-butylphenyl) phosphite (for example, Songnox 1680 manufactured by SONGWON), Tris (nonylphenyl) phosphite (TNPP), Di- (2,4-di-t -Butylphenyl) One or more of pentaerythritol diphosphite can be selected and used.

  The content of the secondary antioxidant is desirably 0.05 to 5 parts by weight. If the content of the secondary antioxidant is less than 0.05 parts by weight, the effect of preventing the deterioration of the polymer is reduced, and if the content of the secondary antioxidant exceeds 5 parts by weight, the secondary secondary antioxidant is excessive. May form phosphorous acid and cause corrosion of processing equipment.

  Sulfur compounds such as distearyl thiodipropionate, ditridecylthiodipropionate, and dilauryl thiodipropionate can be used as the tertiary antioxidant of the present invention, that is, the long-term heat-resistant antioxidant. . As the sulfur-based antioxidant, one or more of distearyl thiodipropionate, ditridecyl thiodipropionate, and dilauryl thiodipropionate can be selected and used.

  It is desirable that the content of the long-term heat resistant antioxidant is 0.1 to 5 parts by weight. If the content of the long-term heat-resistant antioxidant is less than 0.1 parts by weight, the polymer deterioration-preventing effect is reduced. Even if the content of the long-term heat-resistant antioxidant exceeds 5 parts by weight, the polymer deterioration is prevented The effect is not improved further, but rather a long-term heat-resistant antioxidant can be deposited on the surface of the molding.

  In addition to the components described above, the polypropylene resin composition according to the present invention includes additives such as processing lubricants, UV stabilizers, long-term heat stabilizers, antistatic agents, and metal deactivation, as long as the effects of the present invention are not impaired. One or more selected from an agent, a polyethylene wax, an antibacterial agent, and a colorant may be further included.

  As the lubricant, a metal soap lubricant or an amide lubricant is used.

  The metal soap-based lubricant is a substance synthesized by an ester reaction of an organic fatty acid and a metal oxide, and examples thereof include zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, and the like alone or It can be used as a mixture. In particular, it is preferable to use calcium stearate. The metal soap lubricant may be used in an amount of 0 to 5 parts by weight, preferably 0 to 3 parts by weight, based on 100 parts by weight of the polypropylene resin.

  Examples of the amide-based lubricant include ethylene-bis-stearyl-amide, ethylene-bis-oleinamide, glycerin-mono-stearate, sorbitan-monopalmitate, erucamide, etc., which are used alone or as a mixture. be able to. In particular, it is preferred to use ethylene-bis-stearyl-amide. The amide lubricant may be used in an amount of 0 to 5 parts by weight, preferably 0 to 3 parts by weight, based on 100 parts by weight of the polypropylene resin.

  The polyethylene wax is preferably an oligomer in the form of an oligomer having a weight average molecular weight of 100 to 10,000 g / mol by decomposing a high molecular weight polyethylene. The polyethylene wax may be used in an amount of 0 to 10 parts by weight, desirably 0 to 5 parts by weight, based on 100 parts by weight of the polypropylene resin.

  The metal soap lubricant, the amide lubricant and the polyethylene wax can remarkably improve the workability and moldability of the polypropylene resin composition.

  The present invention is further embodied by the following examples, which are used for illustrative purposes only and are not intended to limit the protection scope of the present invention.

<Examples 1-7 and Comparative Examples 1-4>
The contents of block copolypropylene and each additive were measured as shown in Table 1 and mixed with a Henschel mixer, then charged into the main hopper of a twin screw extruder (SMPLATEK, screw diameter 30Φ), and extruded. A polypropylene resin composition was produced by adjusting the barrel temperature of the machine to 150 to 220 ° C. and kneading under an extrusion rate of 10 to 20 kg / hr and a screw rotation speed of 350 rpm.

Flame retardant 1: DBP-TBS Bis (3,5-dibromo-4- (2,3-dibromopropoxy) phenyl) sulfone (manufactured by Suzuki Hiro)
Flame retardant 2: DBP-TBA Tetrabromobisphenol A bis (2,3-dibromopropyl ether) (Dead Sea)
Flame retardant aid: Antimony trioxide (manufactured by Sinochem plastics company)
PP-1: Block copolymer with MI = 1 and elongation of 500% Long-term heat-resistant antioxidant: distantyl thiodipropionate

Experimental example:
Using the resin compositions produced according to the examples and comparative examples, various physical properties were measured as follows.

  (1) Flame retardancy (UL94V-2): Based on the "subjectivity test of plastic materials for machine parts" vertical combustion test (V-2) of UL subject 94 (Underwrites Laboratories Incorporation). The thickness of the test piece used was 0.8 mm.

(2) Blooming resistance: A polypropylene composition was injection molded to produce a test piece thickness of 2.0 mm × width 129 mm × length 118 mm. The injection machine uses a 180-ton injection machine (manufactured by Toyo), the injection temperature is 30/210/220/220/220 ° C. in the order of nozzles in the feeding hopper, the mold temperature is 60 ° C., the injection pressure is 60-100 bar, A specimen for appearance test was manufactured by injection molding at a holding pressure of 700 bar. The 2T specimen was left in an oven at 70 ° C. for 72 hours to evaluate the appearance of the specimen.
O: Good appearance of specimen X: White powder is generated on the specimen surface

(3) Elongation retention rate (%): After injecting a specimen of a polypropylene composition with an ASTM standard No. 1 mold using a 180-ton injection machine (manufactured by Toyo), a temperature of 23 ± 2 ° C. and 50 After storage for 2 days at ± 5% relative humidity, the tensile strength and elongation were measured for elongation at a rate of 50 mm per minute (E1).
This specimen was again heat-treated in a 150 ° C. oven for 70 days, and the elongation was measured under the above conditions (E2). The elongation retention rate was calculated by the following formula 1.
Items not described in this experimental method were performed in accordance with ASTM standard D638 test method.
Elongation retention rate (%) = E2 / E1 × 100 (1)

  (4) Melt index (MI): measured at 230 ° C. (polypropylene) and 190 ° C. (polyethylene) under a load of 2.16 kg based on the ASTM standard D1238 test method.

  According to Table 1 above, it can be seen that, when three or more kinds of antioxidants are used according to the present invention, the elongation retention is 30% or more, and the long-term heat resistance is excellent. However, even if it does not contain any one or contains three or more antioxidants, if it is not included in the weight ratio of the antioxidant according to the present invention, the elongation retention rate is low and long-term heat resistance is insufficient. You can see that

Claims (12)

1 to 30 parts by weight of flame retardant, 0.1 to 5 parts by weight of flame retardant aid, and 0.15 to 15 parts by weight of antioxidant, relative to 100 parts by weight of polypropylene resin,
The antioxidant is a mixture of at least three kinds of antioxidants selected from the group consisting of phenolic antioxidants, aromatic amine antioxidants, phosphorus antioxidants, and sulfur antioxidants. A polypropylene resin composition for corrugated tubes.   The antioxidant mixture comprises a phenolic antioxidant or an aromatic amine antioxidant as a primary antioxidant, a phosphorus antioxidant as a secondary antioxidant, and a sulfur antioxidant as a tertiary oxidation. It uses as an inhibitor, The polypropylene resin composition for corrugated tubes of Claim 1 characterized by the above-mentioned.   The primary antioxidant is included in an amount of 0.1 to 5 parts by weight, the secondary antioxidant is included in an amount of 0.05 to 5 parts by weight, and the tertiary antioxidant is included in an amount of 0.01 to 5 parts by weight. The polypropylene resin composition for corrugated tubes according to claim 2.   2. The polypropylene resin composition for corrugated tubes according to claim 1, wherein the melt index of the polypropylene resin is 0.1 to 3 g / 10 min in the ASTM standard D1238 test method.   The polypropylene resin composition for corrugated tubes according to claim 1, wherein the polypropylene resin is block copolypropylene and has an elongation of 300% or more.   2. The polypropylene resin composition for corrugated tubes according to claim 1, wherein the flame retardant is a halogen flame retardant, a water-containing inorganic compound flame retardant, or a phosphorus flame retardant.   The phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol (BHT), thioethylene bis [2- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadedecyl-3. -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and tetrakis [methyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane It is 1 or more types, The polypropylene resin composition for corrugated tubes of Claim 1 characterized by the above-mentioned.   The aromatic amine-based antioxidant is selected from the group consisting of phenylnaphthylamine, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine, and N, N′-di-2-naphthyl-p-phenylenediamine. The polypropylene resin composition for corrugated tubes according to claim 1, wherein the composition is one or more types.   The phosphorous antioxidant comprises the group consisting of tris (2,4-di-tert-butylphenyl) phosphite, Tris (nonylphenyl) phosphite (TNPP), and Di- (2,4-di-tert-butylphenyl) pentaerythritol diphosphite. The polypropylene resin composition for corrugated tubes according to claim 1, wherein the composition is one or more selected from the above.   The sulfur-based antioxidant is at least one selected from the group consisting of distearyl thiodipropionate, ditridecyl thiodipropionate and dilauryl thiodipropionate. Polypropylene resin composition for corrugated tubes.   It is manufactured with the polypropylene resin composition as described in any one of Claims 1-10, The molded article characterized by the above-mentioned.   The molded article according to claim 11, wherein the molded article is a corrugated tube for an automobile.