KR101725813B1 - Polyketone composition for vehicle hydrogen tank liner - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a polyketone resin composition usable as a material for a hydrogen tank liner for a vehicle, which comprises a polyketone polymer having a hydrogen permeability of 0.1 cc · mm / m ² · atm · day or less at 23 ° C. and 60% RH, And provides a hydrogen tank liner for a vehicle which is improved in gas barrier property, impact strength, heat resistance and abrasion resistance.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyketone composition for automobile hydrogen tank liner,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liner of a hydrogen tank for various vehicles such as automobiles and railways manufactured using a polyketone resin composition. More particularly, the present invention relates to a polyketone resin composition which can be used as a hydrogen tank liner for a vehicle in which a polyketone terpolymer, PA6 and a thermoplastic elastomer are mixed at a certain ratio to improve gas barrier property, impact strength, heat resistance and wear resistance.

Although the production and sales volume of automobiles has temporarily declined due to various factors such as global economic crisis and unstable oil prices, the automobile manufacturing industry will continue to grow steadily in the long term due to the explosive growth of automobile market in emerging countries As such, we believe the development of automotive materials will be encouraged.

The market demand for the characteristics of automotive parts is becoming more and more difficult every year. Especially, special functions such as light weight and high strength are required. This is linked to important development goals of the automotive industry such as fuel economy and safety.

A hydrogen tank for a vehicle is basically necessary for storing compressed air made by an air compressor, and finally it is necessary to stably control the traveling speed of the vehicle. Compressed air discharged from an air compressor interlocked with an engine of a vehicle is stored in a hydrogen tank through an inflow pipe. After being stored, the compressed air is discharged through an outflow pipe again by a brake device and is supplied to a brake chamber and a wheel Through a series of steps to operate the cylinder, the speed of the vehicle is reduced or the vehicle is stopped.

Hydrogen tanks must have basically unintended compressed air outflows and should be able to maintain internal pressure as designed, so that they must have good gas barrier and mechanical strength. In addition, since the inlet and outlet drain valves must be able to control the compressed air efficiently by attaching them to the hydrogen tank in various ways, the material must have related characteristics such as elasticity, heat resistance, thermal conductivity, and abrasion resistance. The development of lightweight materials is required to maintain or improve these characteristics while at the same time achieving the key goals of the automotive industry, including reducing fuel consumption in vehicles.

 Accordingly, although the technology has been developed in such a manner that the material of the hydrogen tank or the material of the liner is treated with a light metal such as an aluminum alloy, even if a light material is adopted, if a hydrogen tank is manufactured using a metal material, It is inevitable to increase the weight of the vehicle body, and therefore there arises a problem that the fuel consumption is increased during running. On the other hand, due to the nature of the metal material, it is difficult to fabricate the hydrogen tank as a single unit. Therefore, it is inevitable to join the joints of the parts by welding, and there is a large possibility that leakage of compressed air occurs. A plan is needed.

In order to solve such a problem, there is a movement to construct a hydrogen tank itself with a polymer polymer or to develop a composite tank having a polymer liner, and polymers such as HDPE, polyamide, polypropylene, and polyethylene have been mainly selected .

US 5,429,845 discloses a compressed gas tank for an automobile, which comprises a non-metallic inner liner made of plastic or other elastomer and which is made integrally by compression molding, blow molding, injection molding or any other generally known technique It describes the patent on storage tanks. In this case, since the inner liner is integrally manufactured by a method such as blow molding, it is possible to prevent the corrosion of the joint portion and the leakage of the compressed gas.

Korean Patent No. 10-0651582 discloses a method of forming a hydrogen tank itself by using fiber reinforced plastics (FRP). The outer surface of the metal brass is covered with a thermoplastic resin in combination with the inlet port, the outlet port and the center cock to form a sheath made of a reinforcing fiber impregnated with a thermosetting resin wound on the outer periphery of the liner to prevent leakage of air to the utmost, The weight of the liner is reduced by replacing the metal with the polymer composite material, and reinforcing fibers are formed outside the liner to prevent leakage of the compressed air.

However, existing resins including HDPE, poly-EEE, polypropylene, and polyethylene still have insufficient abrasion resistance and gas barrier properties to be used as vehicle hydrogen tank liners. In the case of hydrogen tank liners, the strength required for chemical resistance and oil resistance is low, unlike fuel tank or pipe liner, although it may be water resistant. Instead, gas barrier and abrasion resistance are emphasized. In the hydrogen tank, friction occurs frequently in parts fittings and the like. Therefore, there is a problem that when the wear resistance of the liner is poor, the liner is liable to break, and when the gas tank liner of the hydrogen tank liner is insufficient, There is a problem in that it can not perform its role as a user. It is also necessary to improve the properties of the hydrogen tank liner for automobiles, heat resistance and impact resistance.

Korean Patent No. 1004453540000 Korean Patent No. 1008108650000

The present invention was made to solve the problems of the above-mentioned hydrogen tank material, and it was used as a hydrogen tank liner for a vehicle having improved gas barrier property, impact strength, heat resistance and wear resistance by mixing polyketone terpolymer, PA6 and thermoplastic elastomer at a certain ratio It is an object of the present invention to provide a polyketone resin composition.

In order to solve the above problems,

A polyketone resin composition having a hydrogen permeability of not more than 0.1 cc / mm ² / atm 占 day at 23 占 폚 and 60% RH as a linear alternating polyketone copolymer comprising carbon monoxide and at least one olefinically unsaturated hydrocarbon, And the hydrogen tank liner for a vehicle, which is manufactured by injection molding, is provided as means for solving the problems.

The polyketone copolymer is characterized in that the unit represented by the following formula (1) contains a repeating unit.

 [Chemical Formula 1]

- {- CO- (-CH ₂ -CH ₂ -) -} x- {CO- (G) -} y-

In order to solve the above-mentioned problem, the polyketone resin composition of the present invention is prepared by mixing 80 wt% of the polyketone copolymer, 10 wt% of nylon 6 and 10 wt% of maleic anhydride-grafted TPE .

On the other hand, the polyketone copolymer may be prepared by preparing a catalyst composition comprising a palladium compound, an acid having a pKa value of 6 or less, and a bidentate compound of phosphorus; Preparing a mixed solvent of methanol and water; Conducting the polymerization in the presence of the catalyst composition and the mixed solvent to prepare a linear terpolymer of carbon monoxide, ethylene and propylene; Removing the remaining catalyst composition from the prepared linear terpolymer using a solvent to obtain a polyketone polymer; Lt; / RTI >

The polyketone resin composition prepared according to the present invention is excellent in gas barrier property, impact strength, heat resistance, and abrasion resistance, and thus is very suitable for a hydrogen tank liner for a vehicle.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. However, these examples are merely for a better understanding of the present invention and are not intended to limit the scope of the present invention. The present invention can be grasped in detail by the following examples.

 Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

The present invention relates to a polyketone resin composition which can be used as a hydrogen tank liner for a vehicle, and is characterized in that a polyketone terpolymer, PA6 and a thermoplastic resin are mixed at a certain ratio.

The polyketone terpolymer is a new resin developed in recent years and is excellent in mechanical properties such as impact strength and molding properties and is a thermoplastic synthetic resin which is usefully applied to various molded articles and parts. The mechanical properties of polyketone polymers belong to the category of high performance plastics, and they are attracting much attention as eco-friendly materials as well as being a polymer material synthesizing carbon monoxide as a raw material.

The polyketone terpolymer has lower moisture absorption than nylon (0.45%, 50% RH, 23 ℃), which makes it possible to design various products with less change in dimensions and physical properties due to moisture absorption. Particularly, since the polyketone polymer has a density lower than that of aluminum (1.24 g / cm ³ ), it is very suitable for weight reduction of products.

Polyketone polymers are generally synthesized from carbon monoxide and olefins. For example, U.S. Patent No. 4,843,144 discloses line alternating polymers synthesized from olefins such as ethylene and propylene and carbon monoxide. The polyketone resin produced in this patent has been shown to have excellent impact resistance, high rebound resilience at room temperature and low temperature, and excellent creep properties.

In recent years, among polyketones, there is a growing interest in a series of alternating polyketones in which ketone groups and at least one ethylenically unsaturated hydrocarbon are alternately polymerized and formed to improve mechanical properties and molding properties. For example, U.S. Patent No. 4,880,903 discloses a polyketone terpolymer in which ketone groups, ethylene, and other olefinically unsaturated hydrocarbons (such as propylene) are alternately polymerized and formed. The contents of the aforementioned U.S. Patent Nos. 4,843,144 and 4,880,903 are incorporated herein by reference.

A polyketone terpolymer as a main component of a hydrogen tank liner for a vehicle of the present invention is a linear alternating structure composed of a ketone group and at least one ethylenically unsaturated hydrocarbon and contains substantially one carbon monoxide (or a ketone group) per one ethylenically unsaturated hydrocarbon And has excellent physical properties, appearance characteristics and molding properties.

 Ethylenically unsaturated hydrocarbons suitable for use as the precursor of the polyketone polymer are selected from the group consisting of ethene,? -Olefins (such as propene, 1-butene, etc.) having up to 20 carbon atoms, preferably up to 10 carbon atoms aliphatic hydrocarbons such as butene, isobutene, 1-hexene and 1-octene, or aryl aliphatic hydrocarbons in which an aryl substituent is formed on the aliphatic molecule, Is an aryl aliphatic hydrocarbon in which an aryl substituent is formed on the sulfide. Examples of the aryl aliphatic hydrocarbon among the ethylenic unsaturated hydrocarbons include styrene, p-methylstyrene, ethylstyrene and m-isopropyl styrene.

Such ethylenically unsaturated hydrocarbons and ketone compounds are copolymerized to form a linear alternating polyketone. Among them, a linear alternating polyketone formed by copolymerization of ethene and a ketone compound, or a mixture of at least three Linear alternating polyketone formed by copolymerization of an ethylenically unsaturated hydrocarbon having a carbon atom is preferable in view of the fact that the copolymerization reaction is easy and the molecular weight of the copolymerized linear alternating polyketone is relatively uniform. In short, preferred polyketone polymers are copolymers of carbon monoxide and ethene, more preferably an olefin such as a second ethylenically unsaturated hydrocarbon (especially propylene) having carbon monoxide and ethylene and at least three carbon atoms and Of terpolymer.

Preferred polymeric rings of the polyketone polymers in the present invention can be represented by the following formula (1).

[Chemical Formula 1]

- [CO- (-CH2-CH2-)] x- [CO- (G)] y-

In the above formula (1), G is an ethylenically unsaturated hydrocarbon, particularly an ethylenically unsaturated hydrocarbon having at least three carbon atoms, and x: y is preferably at least 1: 0.01.

In another embodiment, the polyketone polymer is a copolymer comprising repeating units represented by the general formulas (1) and (2), and y / x is preferably 0.03 to 0.3. When the value of the y / x value is less than 0.03, there is a limit in that the meltability and processability are inferior. When the value of y / x is more than 0.3, the mechanical properties are poor. Further, y / x is more preferably 0.03 to 0.1.

- [- CH2CH2-CO] x- (1)

- [- CH2 --CH (CH3) - CO] y - (2)

In addition, the melting point of the polymer can be controlled by controlling the ratio of ethylene to propylene in the polyketone polymer. For example, when the molar ratio of ethylene: propylene: carbon monoxide is adjusted to 46: 4: 50, the melting point is about 220 ° C, while the melting point is adjusted to 235 ° C when the molar ratio is adjusted to 47.3: 2.7: 50.

Particularly preferred are polyketone polymers having a number average molecular weight of from 100 to 200,000, especially from 20,000 to 90,000, as measured by gel permeation chromatography. The physical properties of the polymer are determined according to the molecular weight, depending on whether the polymer is a copolymer or a terpolymer and, in the case of a terpolymer, the properties of the second hydrocarbon part. The melting point of the total of the polymers used in the present invention is 175 ° C to 300 ° C, and generally 210 ° C to 270 ° C. The intrinsic viscosity (LVN) of the polymer measured by HFIP (hexafluoroisopropyl alcohol) at 60 DEG C using a standard tubular viscosity measuring apparatus is 0.5 dl / g to 10 dl / g, preferably 0.8 dl / g to 4 dl / g, And more preferably 1.0 dl / g to 2.0 dl / g. If the intrinsic viscosity is less than 0.5 dl / g, the mechanical properties are deteriorated. If the intrinsic viscosity exceeds 10 dl / g, the workability is deteriorated.

On the other hand, the molecular weight distribution of the polyketone is preferably 1.5 to 2.5, more preferably 1.8 to 2.2. When the ratio is less than 1.5, the polymerization yield decreases. When the ratio is 2.5 or more, the moldability is poor. In order to control the molecular weight distribution, it is possible to adjust proportionally according to the amount of the palladium catalyst and the polymerization temperature. That is, when the amount of the palladium catalyst is increased or when the polymerization temperature is 100 ° C or higher, the molecular weight distribution becomes larger. The melting point of the polyketone polymer is usually in the range of 175 ° C to 300 ° C, specifically 210 ° C to 270 ° C.

In the present invention, 75 to 85% by weight of a polyketone copolymer, 5 to 15% by weight of nylon and 5 to 15% by weight of a maleic anhydride-grafted TPE are preferable in order to improve the heat resistance of the polyketone resin composition. 5% to 15% by weight of PA6 relative to the total polyketone composition is added. If the amount is less than 5% by weight, heat resistance of the resin can not be sufficiently secured. If the amount exceeds 15% by weight, inherent hydrogen barrier properties of the polyketone may be deteriorated.

Further, in the present invention, a thermoplastic elastomer (TPE) is further mixed to improve the mechanical properties such as molding, processability and the like of the polyketone resin composition. The TPE is preferably a grafted maleic anhydride.

At this time, the amount of TPE to be added is preferably 5% by weight to 15% by weight based on the total weight of the composition. If it is added in an amount of less than 5% by weight, the processability is deteriorated. If it exceeds 15% by weight, the processability is not improved and the production cost is increased and the inherent physical properties of the polyketone are deteriorated.

The polyketone resin composition of the present invention is obtained by melt-blending the respective components at a temperature of 230 ° C using a co-directional twin screw extruder, pelletizing the components, and injecting the mixture at 180-280 ° C to form the polyketone resin composition of the present invention Can be manufactured.

 More specifically, there is provided a method for preparing a catalyst composition, comprising: preparing a catalyst composition comprising a palladium compound, an acid having a pKa value of 6 or less, and a bidentate compound of phosphorus; Preparing a mixed solvent of methanol and water; Conducting the polymerization in the presence of the catalyst composition and the mixed solvent to prepare a linear terpolymer of carbon monoxide, ethylene and propylene; Removing the remaining catalyst composition from the linear terpolymer with a solvent (e.g., alcohol and acetone) to obtain a polyketone polymer; And a step of mixing (melt-kneading) the polyketone polymer with graphite and extruding the polyketone polymer to produce the polyketone composition of the present invention.

 The reaction temperature in the polymerization is suitably in the range of 50 to 100 ° C and the reaction pressure in the range of 40 to 60 bar. The resulting polymer is recovered through filtration and purification processes after polymerization, and the remaining catalyst composition is removed with a solvent such as alcohol or acetone. The extrusion temperature is preferably 230 to 260 占 폚, and the screw rotation speed is preferably in the range of 100 to 300 rpm.

The polyketone resin composition of the present invention is excellent in impact resistance, chemical resistance, low density, dimensional stability, and moisture absorption resistance, and can be applied to various fields other than a hydrogen tank liner for a vehicle.

Example 1

The linear alternating polyketone terpolymer of carbon monoxide and ethylene and propene is prepared by reacting palladium acetate, trifluoroacetic acid and ((2,2-dimethyl-1,3-dioxane-5,5-diyl) bis (methylene) Bis (2-methoxyphenyl) phosphine). In the above, the content of trifluoroacetic acid with respect to palladium was 10 times the molar ratio, and the two steps of 1 stage of polymerization temperature 78 ° C and 84 ° C were carried out. The molar ratio of ethylene to propene in the polyketone terpolymer prepared above is 46 to 4. The melting point of the polyketone terpolymer was 220 占 폚, the LVN measured at 25 占 폚 by HFIP (hexa-fluoroisopropano) was 1.4 dl / g, the MI index was 60 g / 10 min and the MWD was 2.0. [0050] A mixture of 80 wt% of the polyketone terpolymer prepared above, 10 wt% of nylon 6, 10 wt% of maleic anhydride grafted TPE, The specimens were prepared by injection on an extruder using screws. In order to evaluate the gas barrier properties, specimens were processed into film form and evaluated for their physical properties.

Example 2

The linear alternating polyketone terpolymer of carbon monoxide and ethylene and propene is prepared by reacting palladium acetate, trifluoroacetic acid and ((2,2-dimethyl-1,3-dioxane-5,5-diyl) bis (methylene) Bis (2-methoxyphenyl) phosphine). In the above, the content of trifluoroacetic acid with respect to palladium was 10 times the molar ratio, and the two steps of 1 stage of polymerization temperature 78 ° C and 84 ° C were carried out. The molar ratio of ethylene to propene in the polyketone terpolymer prepared above is 46 to 4. The melting point of the polyketone terpolymer was 220 占 폚, the LVN measured at 25 占 폚 by HFIP (hexa-fluoroisopropano) was 1.6 dl / g, the MI index was 60 g / 10 min and the MWD was 2.0. [0050] A mixture of 80 wt% of the polyketone terpolymer prepared above, 10 wt% of nylon 6, 10 wt% of maleic anhydride grafted TPE, The specimens were prepared by injection on an extruder using screws. In order to evaluate the gas barrier properties, specimens were processed into film form and evaluated for their physical properties.

Example 3

The linear alternating polyketone terpolymer of carbon monoxide and ethylene and propene is prepared by reacting palladium acetate, trifluoroacetic acid and ((2,2-dimethyl-1,3-dioxane-5,5-diyl) bis (methylene) Bis (2-methoxyphenyl) phosphine). In the above, the content of trifluoroacetic acid with respect to palladium was 10 times the molar ratio, and the two steps of 1 stage of polymerization temperature 78 ° C and 84 ° C were carried out. The molar ratio of ethylene to propene in the polyketone terpolymer prepared above is 46 to 4. The melting point of the polyketone terpolymer was 220 占 폚, the LVN measured at 25 占 폚 by HFIP (hexa-fluoroisopropano) was 2.0 dl / g, the MI index was 60 g / 10 min and the MWD was 2.0. [0050] A mixture of 80 wt% of the polyketone terpolymer prepared above, 10 wt% of nylon 6, 10 wt% of maleic anhydride grafted TPE, The specimens were prepared by injection on an extruder using screws. In order to evaluate the gas barrier properties, specimens were processed into film form and evaluated for their physical properties.

Example 4

The linear alternating polyketone terpolymer of carbon monoxide and ethylene and propene is prepared by reacting palladium acetate, trifluoroacetic acid and ((2,2-dimethyl-1,3-dioxane-5,5-diyl) bis (methylene) Bis (2-methoxyphenyl) phosphine). In the above, the content of trifluoroacetic acid with respect to palladium was 10 times the molar ratio, and the two steps of 1 stage of polymerization temperature 78 ° C and 84 ° C were carried out. The molar ratio of ethylene to propene in the polyketone terpolymer prepared above is 46 to 4. The melting point of the polyketone terpolymer was 220 占 폚, the LVN measured at 25 占 폚 by HFIP (hexa-fluoroisopropano) was 1.2 dl / g, the MI index was 60 g / 10 min and the MWD was 2.0. [0050] A mixture of 80 wt% of the polyketone terpolymer prepared above, 10 wt% of nylon 6, 10 wt% of maleic anhydride grafted TPE, The specimens were prepared by injection on an extruder using screws. In order to evaluate the gas barrier properties, specimens were processed into film form and evaluated for their physical properties.

Comparative Example 1

A specimen was prepared by extruding a twin screw having a diameter of 40 mm and L / D = 32, which was operated at 250 rpm using HDPE as a material of DuPont. In order to evaluate the gas barrier properties, specimens were processed into film form and evaluated for their physical properties.

The pellets obtained in the above Examples and Comparative Examples were used to prepare specimens for use in an automobile hydrogen tank liner. The properties were evaluated according to the following methods, and the results are shown in Table 1.

Property evaluation method

1. Hydrogen barrier property: Hydrogen permeability was measured for each film sample using MOCON OX-TRAN 2/20. 23 C, 60% RH. The hydrogen permeability at 1 atm was measured and converted to a film thickness of 1 mm.

2. Izod Impact Strength: ASTM D-256 was used.

3. Heat resistance: ASTM D-648 was used. The standard value should be 185 ℃ or higher (heat distortion temperature).

4. Ring-on-Ring Type (Resin): A through-type test piece having an outer diameter of 25.6 mm, an inner diameter of 20 mm and a height of 15 mm was injection-molded and fixed to a testing machine. A press load of 6.6 kgf The test is carried out under the driving conditions of a speed of 10 cm / s. At this time, the non-abrasion amount was calculated using the following formula to evaluate the abrasion resistance. The smaller the amount of non-abrasion obtained, the better the abrasion resistance.

Non-wear amount = Wear weight (mg) / [Density (mg / mm ³ ) X Pressure load (kgf) X Travel distance (km)]

* Test equipment: Trust type (Friction type abrasion tester)

division Gas barrier property
cc · mm / m ² · atm · day
(23 ° C and 60% RH) Impact strength
KJ / m ² Heat resistance (℃) Wear amount
mm ³ / kg / km Example 1 0.05 28.5 195 1.12 Example 2 0.07 31.2 198 0.89 Example 3 0.06 33.4 197 0.72 Example 4 0.05 28.0 191 1.14 Comparative Example 1 5.65 23.2 168 11.2

In Table 1, the polyketone resin composition prepared according to the present invention is excellent in gas barrier property, impact resistance, heat resistance, and abrasion resistance, and thus is suitable for use as a material for a vehicle hydrogen tank liner. In particular, the film sample of the present invention was evaluated as having excellent hydrogen permeability of less than 0.1 cc · mm / m ² · atm · day at 23 ° C. and 60% RH.

Claims (5)

A polyketone resin composition having a hydrogen permeability of not more than 0.1 cc mm / m ² · atm · day under conditions of 23 ° C. and 60% RH, which is a linear alternating polyketone copolymer composed of carbon monoxide and at least one olefinically unsaturated hydrocarbon, Molded by injection molding,
((2,2-dimethyl-1,3-dioxane-5,5-diyl) bis (methylene)) bis (bis (2- methoxyphenyl) phosphine) catalyst used in the polymerization of the polyketone copolymer Pin) is used for the hydrogen tank liner for a vehicle.
The method according to claim 1,
Wherein the polyketone resin composition comprises 75 to 85% by weight of the polyketone copolymer, 5 to 15% by weight of nylon 6, and 5 to 15% by weight of maleic anhydride grafted TPE. Liner.
The method according to any one of claims 1 to 3,
Wherein the polyketone copolymer comprises a repeating unit represented by the following formula (1) and G is an ethylenically unsaturated hydrocarbon.
[Chemical Formula 1]
- {- CO- (-CH ₂ -CH ₂ -) -} x- {CO- (G) -} y-
(x and y represent the molar ratio of each polymer and y / x is 0.03 to 0.3).
The method of claim 3,
Wherein the polyketone copolymer has an intrinsic viscosity of 1.0 to 2.0 dl / g and a molecular weight distribution of 1.5 to 2.5.
5. The method of claim 4,
Wherein the polyketone copolymer comprises a catalyst composition comprising a palladium compound, an acid having a pKa value of 6 or less, and a bidentate compound of phosphorus;
Preparing a mixed solvent of methanol and water;
Conducting the polymerization in the presence of the catalyst composition and the mixed solvent to prepare a linear terpolymer of carbon monoxide, ethylene and propylene;
Removing the remaining catalyst composition from the prepared linear terpolymer using a solvent to obtain a polyketone polymer; Wherein the hydrogen tank liner is made of a synthetic resin.