A balance weight composition with excellent chemical resistance and a balance weight containing the same.

Abstract

The present invention provides a balance weight composition that exhibits excellent adhesion to the curved surface of vehicle wheels, is easy to mold, and has excellent durability and flexibility, remaining unbroken even during repetitive work. [Solution] A balance weight composition comprising polar rubber; an activator; and metal particles; wherein the balance weight composition comprises 1.5 phr or more and less than 60 phr of the activator; and more than 350 phr but less than 1,750 phr of the metal particles, based on 100 parts by weight (phr) of the polar rubber.

Description

[Technical Field]

[0001] The present invention relates to a balance weight composition with excellent chemical resistance and a balance weight containing the same, and more specifically, to a composition containing polar rubber, an activator and metal particles, which can achieve excellent chemical resistance. [Background technology]

[0002] Generally, if there is an imbalance in the wheel of a car, vibrations will occur due to centrifugal force from rotation, which can lead to noise, uneven tire wear, and steering wheel vibration. In particular, when driving at high speeds, accurate wheel balance is essential. To correct an imbalance in a car wheel, a wheel balance weight of appropriate weight should be placed on any part of the edge opposite the part of the wheel or rim where the weight imbalance occurs, thereby generating centrifugal force in the opposite direction and achieving balance.

[0003] Conventionally, a known method for using balance weights is to attach weights made of lead (Pb) in 5g units to the tire or rim using tape-type adhesive. However, lead (Pb) is classified as an environmentally hazardous substance, and when left for a long period, it corrodes in saltwater. Furthermore, its lack of flexibility and the use of 5g units lead to reduced precision. In addition, the use of tape-type adhesive, when applied to the curved surface of an automobile wheel, leads to problems such as reduced adhesion, interfacial delamination, and lifting during long-term use. Moreover, conventional balance weights cannot be manufactured using automated processes and must be done manually, inevitably leading to a high frequency of errors. [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention aims to solve the above-mentioned problems and to provide a balance weight composition that has excellent adhesion to the curved surface of a vehicle's wheel, is easy to mold, and has excellent durability and flexibility that prevents breakage even during repetitive work.

[0005] In particular, we aim to provide a balance weight composition that exhibits excellent robustness under a variety of chemical durability conditions.

[0006] The objectives of the present invention are not limited to those mentioned above. The objectives of the present invention will become clearer in the following description and will be achieved by the means and combinations thereof described in the claims. [Means for solving the problem]

[0007] According to one embodiment of the present invention, a balance weight composition can be provided comprising polar rubber, an activator, and metal particles, wherein, based on 100 parts by weight (phr) of the polar rubber, the activator is present in an amount of 1.5 phr or more and less than 60 phr, and the metal particles are present in an amount exceeding 350 phr and less than 1,750 phr.

[0008] The polar rubber may include any one selected from the group consisting of nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (H-NBR), chloroprene rubber (CR), and combinations thereof.

[0009] In this case, the nitrile butadiene rubber may include one having a Mooney viscosity (ML1+4) of 40 to 75 at 100°C.

[0010] The hydrogenated nitrile butadiene rubber may include one having a Mooney viscosity (ML1+4) of 55 to 75 at 100°C.

[0011] Furthermore, the chloroprene rubber may include one having a Mooney viscosity (ML1+4) of 30 to 60 at 100°C.

[0012] In one embodiment, the activator may include one selected from inorganic oxides, fatty acids, and combinations thereof.

[0013] The inorganic oxide may include any one selected from the group consisting of zinc oxide (ZnO), tin oxide (SnO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), and combinations thereof.

[0014] The fatty acids are selected from saturated fatty acids and unsaturated fatty acids. The saturated fatty acids include one selected from the group consisting of stearic acid, caprylic acid, lauric acid, myristic acid, arachidic acid, and combinations thereof. The unsaturated fatty acids may include one selected from the group consisting of oleic acid, elaidic acid, linoleic acid, ricinoleic acid, and combinations thereof.

[0015] In one embodiment, the balance weight composition may contain 1 phr or more and less than 55 phr of the inorganic oxide, and 0.5 phr to 5 phr of the fatty acid.

[0016] The metal particles may include any one selected from the group consisting of austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and combinations thereof.

[0017] Furthermore, the average particle size (D50) of the metal particles can be between 1 μm and 150 μm.

[0018] Furthermore, the metal particles have a particle size of 30 μm to 120 μm, and the tap density of the metal particles is 6.0 g / cm³. 3 ~10.0g / cm 3 The apparent density of the metal particles is 4.0 g / cm³. 3 ~8.0g / cm 3 It is possible.

[0019] In one embodiment, the balance weight composition may further contain a plasticizer.

[0020] The plasticizer can include any one selected from the group consisting of paraffinic compounds, naphthenic compounds, olefinic compounds, aromatic compounds, and combinations thereof.

[0021] Also, the balance weight composition can include more than 0 phr and 30 phr or less of the plasticizer.

[0022] In one embodiment, it can further include any one selected from the group consisting of an acid acceptor, an antioxidant, a filler, and combinations thereof.

[0023] In one embodiment, based on 100 parts by weight (phr) of the polar rubber, it can include 1 phr to 2 phr of an inorganic oxide, 0.8 phr to 2 phr of a fatty acid, 5 phr to 30 phr of a plasticizer, and 500 phr to 1,580 phr of the metal particles.

[0024] In one embodiment, the balance weight composition may not include a crosslinking agent and a crosslinking accelerator.

[0025] According to another embodiment of the present invention, a balance weight obtained by compression molding the balance weight composition can be provided.

[0026] At this time, the balance weight can be applied to a vehicle wheel.

Advantages of the Invention

[0027] The balance weight composition according to the present invention includes a polar rubber excellent in chemical resistance such as heat resistance, hydrolysis resistance, fuel resistance, weather resistance, ozone resistance, etc., and metal particles with a high specific gravity, thereby providing a high specific gravity balance weight composition excellent in chemical resistance. Also, by using stainless steel powder as the metal particles, the corrosion resistance can be improved.

[0028] The balance weight composition according to the present invention is easily moldable, and a balance weight to which the composition is applied can have excellent adhesion to the curved surface of a vehicle's wheel.

[0029] Furthermore, balance weights to which the balance weight composition according to the present invention is applied have fatigue resistance to repeated bending that may occur during mass production manufacturing processes and balancing operations of products, thereby improving the problem of reduced productivity.

[0030] Furthermore, when a molded body to which the balance weight composition according to the present invention is applied can improve the rate of work defects by more than 50% compared to conventional steel-type products when applied to a wheel. In addition, a molded body to which the composition according to the present invention is applied can be precisely balanced in small units of 0.5g, can achieve a low wheel balancing error rate, can minimize noise generation in the vehicle's driving mode, and can minimize interference with the brake caliper.

[0031] The effects of the present invention are not limited to those mentioned above. The effects of the present invention should be understood to include all effects that can be inferred from the following description. [Brief explanation of the drawing]

[0032] [Figure 1] This is a photograph of a balance weight to which a film has been attached, to which a composition according to one embodiment of the present invention has been applied. [Figure 2] These are photographs showing the results of the bendability evaluation of the balance weights in Example 1, Example 3, and Comparative Example 2. [Figure 3] This is a photograph showing the weather resistance evaluation results for the balance weight related to Comparative Example 3. [Figure 4] This is a photograph showing the results of the ozone resistance evaluation for the balance weight related to Reference Example 9. [Modes for carrying out the invention]

[0033] The above-described objectives, other objectives, features, and advantages of the present invention will be readily apparent through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments presented herein are provided to make the disclosed content thorough and complete and to fully convey the idea of ​​the invention to the ordinary person in the art.

[0034] In describing each drawing, similar reference numerals were used for similar components. In the accompanying drawings, the dimensions of each structure are enlarged for clarity of the invention. Terms such as "first," "second," etc., may be used to describe various components, but each component should not be limited by such terms. Each term is used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the invention, the first component may be named the second component, and the second component may also be named the first component. Singular expressions include plural expressions unless they have a clearly different meaning in context.

[0035] In this specification, terms such as “includes” or “having” are used to specify the presence of features, numbers, stages, operations, components, parts, or combinations thereof as described in the specification, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, numbers, stages, operations, components, parts, or combinations thereof. Furthermore, when a part such as a layer, film, region, or plate is said to be “on top” of another part, this includes not only when it is “directly on top” of the other part, but also when there are other parts in between. Conversely, when a part such as a layer, film, region, or plate is said to be “below” another part, this includes not only when it is “directly below” the other part, but also when there are other parts in between.

[0036] Unless otherwise explicitly stated, all numbers, values, and / or expressions used herein to express quantities of components, reaction conditions, polymer compositions, and formulations should be understood to be, in all cases, modified by the term “approximately,” as these numbers are approximations that reflect the various uncertainties of measurement that arise in obtaining such values. Furthermore, where numerical ranges are disclosed herein, such ranges are continuous and, unless otherwise noted, include all values ​​from the minimum to the maximum value of such range. Additionally, where such ranges refer to integers, unless otherwise noted, include all integers from the minimum to the maximum value of such range.

[0037] In this specification, when a range is described for a variable, the variable may be understood to include all values ​​within the described range, including each of the described endpoints. For example, the range "5 to 10" may be understood to include not only the values ​​5, 6, 7, 8, 9, and 10, but also any sub-ranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and any values ​​between each integer that is appropriate within the described range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, and 6.5 to 9. Similarly, the range "10% to 30%" may be understood to include not only all integers up to 30% such as 10%, 11%, 12%, 13%, etc., but also any sub-ranges such as 10% to 15%, 12% to 18%, 20% to 30%, etc., and any values ​​between each integer that is appropriate within the described range, such as 10.5%, 15.5%, 25.5%, etc.

[0038] The balance weight composition according to the present invention may contain polar rubber, an activator, and metal particles. By using a mixture of polar rubber, which has excellent chemical resistance and elasticity, and metal particles with a high specific gravity, the balance weight composition according to the present invention can suppress rust formation, suppress environmental pollution by heavy metals, have excellent adhesion to the curved surface of the wheel, have excellent extrudeability and bending resistance, and can suppress the occurrence of interfacial peeling and lifting phenomena.

[0039] In this case, the balance weight composition may contain 1.5 phr or more and less than 60 phr of the activator, and more than 350 phr but less than 1,750 phr of metal particles, based on 100 parts by weight (phr) of the polar rubber. When the balance weight composition satisfies the above composition, it may have excellent compoundability and flexibility, high specific gravity, and well-balanced and excellent chemical resistance, including fuel resistance, ozone resistance, and weather resistance.

[0040] The following will provide a more detailed explanation of each component included in the balance weight composition.

[0041] Polar rubber

[0042] The balance weight composition according to the present invention contains polar rubber. The polar rubber refers to rubber that has polar atomic groups in its molecules and has a large dipole moment, and has excellent heat resistance, hydrolysis resistance, weather resistance, and ozone resistance. Furthermore, due to its high polarity, the polar rubber has excellent miscibility with metal materials.

[0043] The polar rubber may include, for example, any one selected from the group consisting of nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (H-NBR), chloroprene rubber (CR), and combinations thereof.

[0044] The polar rubbers containing nitrile butadiene rubber, hydrogenated nitrile butadiene rubber, or chloroprene rubber contain acrylonitrile groups (NBR, H-NBR) and chlorine functional groups (CR) which have excellent fuel resistance to fuels such as gasoline, thus improving chemical resistance.

[0045] The aforementioned nitrile butadiene rubber exhibits excellent resistance to a wide range of organic solvents and automotive lubricants, as well as superior tensile strength, tear resistance, and low-temperature flexibility. Furthermore, as a general-purpose material, the nitrile butadiene rubber has the advantages of being economical and readily available. Examples of the aforementioned nitrile butadiene rubber include KRYNAC 3345F, PERBUNAN N3445 (Arlanxeo), and Nipol 1072 (Zeon).

[0046] The aforementioned hydrogenated nitrile butadiene rubber exhibits even greater heat resistance than nitrile butadiene rubber and can generally be used in environments above 150°C. Furthermore, the hydrogenated nitrile butadiene rubber has excellent chemical resistance, resulting in good resistance to oils, fuels, and lubricants, as well as superior oxidation stability and ozone resistance. In addition, its excellent abrasion resistance ensures physical stability when used in balance weights. Examples of the aforementioned hydrogenated nitrile butadiene rubber include THERBAN 3407, THERBAN 3406 (Arlanxeo), ZETPOL 2000, and ZETPOL 2020 (Zeon).

[0047] The chloroprene rubber has chlorine polar groups and exhibits excellent ozone resistance and weather resistance. Furthermore, the chloroprene rubber has excellent chemical resistance, resulting in good resistance to oil, fuel, and lubricants, as well as excellent heat resistance and flame retardancy, ensuring fire stability when applied to automotive parts under high temperature and heat conditions. Examples of the chloroprene rubber include Neoprene AD10, Neoprene WRT, and Neoprene FB (Denka).

[0048] In one embodiment, the nitrile butadiene rubber may have a Mooney viscosity (ML1+4) of 40 to 75 at 100°C, the hydrogenated nitrile butadiene rubber may have a Mooney viscosity (ML1+4) of 55 to 75 at 100°C, and the chloroprene rubber may have a Mooney viscosity (ML1+4) of 30 to 60 at 100°C.

[0049] If the Mooney viscosity (ML1+4) of the polar rubber at 100°C is excessively low, it has the disadvantage of reduced mechanical properties, and if the Mooney viscosity (ML1+4) of the polar rubber at 100°C is excessively high, it has the disadvantage of reduced processability.

[0050] Activator

[0051] The balance weight composition according to the present invention contains an activator. The activator can improve the compatibility and dispersibility between the components contained in the balance weight composition and improve the packing properties of the stainless steel powder.

[0052] In one embodiment, the activator may include one selected from inorganic oxides, fatty acids, and combinations thereof.

[0053] The inorganic oxide may include, for example, any one selected from the group consisting of zinc oxide (ZnO), tin oxide (SnO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), and combinations thereof. Preferably, zinc oxide can be used, as it can improve the dispersibility of polar rubber during the extrusion process.

[0054] The fatty acid is selected from saturated fatty acids and unsaturated fatty acids. The saturated fatty acid includes, for example, one selected from the group consisting of stearic acid, caprylic acid, lauric acid, myristic acid, arachidic acid, and combinations thereof. The unsaturated fatty acid may include, for example, one selected from the group consisting of oleic acid, elaidic acid, linoleic acid, ricinoleic acid, and combinations thereof. Preferably, stearic acid, which does not produce non-uniform particles when compounding polar rubber and has excellent solubility, can be used.

[0055] In the case of polar rubber, since its specific gravity is relatively low, metal particles are included to increase the specific gravity of the balance weight composition. However, if the metal particles are included in a predetermined amount or more, problems such as a decrease in compoundability and flexibility may occur, making it difficult to increase the content of metal particles indefinitely. The balance weight composition according to the present invention can compensate for the decrease in specific gravity of the balance weight caused by polar rubber having a low specific gravity by including an inorganic oxide with a high specific gravity as an activator.

[0056] Furthermore, since the polar rubber and inorganic oxide contained in the balance weight composition according to the present invention have good fusion properties with each other, the mixing efficiency is improved, and as will be described later, the inorganic oxide content can be increased to less than 55 phr.

[0057] In one embodiment, the balance weight composition may contain 1 phr or more and less than 55 phr of the inorganic oxide, and 0.5 phr to 5 phr of the fatty acid, based on 100 phr of the polar rubber.

[0058] If the inorganic oxide content is less than 1 phr, the activation effect is insufficient, making effective mixing difficult, which can cause the metal particles in powder form to separate. If the inorganic oxide content is 55 phr or more, aggregation of the metal particle powder may occur, and the fatigue resistance may decrease due to reduced dispersibility.

[0059] If the fatty acid content is less than 0.5 phr, it becomes difficult to ensure proper packing of the metal particles, which may result in separation and cracking of the metal particles. Furthermore, if the fatty acid content exceeds 5 phr, unreacted fatty acids accumulate, which may cause separation of metal particles during mixing of the composition, leading to discoloration and / or color transfer.

[0060] metal particles

[0061] The balance weight composition according to the present invention may contain metal particles. The metal particles increase the specific gravity of the balance weight composition, which can result in superior corrosion resistance compared to conventional steel-type balance weights.

[0062] The metal particles may be in powder form and may include metals that have high density and specific gravity while possessing corrosion resistance. For example, the metal particles may include stainless steel, titanium, nickel, chromium, zinc, copper, nickel-copper alloy (Monel), nickel-chromium alloy (Inconel), nickel-molybdenum-chromium alloy (Hastelloy), etc. Preferably, stainless steel powder, which has excellent corrosion resistance and high density and specific gravity, can be used as the metal particles.

[0063] The stainless steel powder can be at least one steel grade selected from the SUS 300 series, SUS 400 series, and SUS 600 series, which have excellent corrosion resistance.

[0064] The SUS 300 series includes austenitic stainless steel, which can exhibit excellent toughness and flexibility. Specific examples of the SUS 300 series include SUS 304, 309, 310, 314, 330, 303, 316, and 317, with SUS 304 being preferred.

[0065] The SUS 400 series includes ferritic stainless steel and may be magnetic. Specific examples of the SUS 400 series include SUS 430, 444, 434, 436, 405, and 409, with SUS 430 being preferred.

[0066] The aforementioned SUS 600 series includes martensitic stainless steel, which can have excellent strength and corrosion resistance. Specific examples of the SUS 600 series include SUS 630 and 631, and preferably, SUS 630 can be used.

[0067] The shape of the metal particles can be amorphous, plate-like, or spherical, and all of them can be used. Preferably, spherical powder can be used to improve the dispersibility. The metal particles in powder form can be produced by a water injection or gas injection method.

[0068] The average particle size (D50) of the metal particles can be from 1 μm to 150 μm, preferably from 30 μm to 120 μm. When having such an average particle size, it has excellent dispersibility, excellent filling rate, and can contribute to ensuring mechanical properties. When the average particle size of the powder is less than 1 μm or greater than 150 μm, the dispersibility may decrease due to aggregation of the powder particles, or the filling rate may be low, and the specific gravity of the composition may decrease. In this specification, D50 can be the particle size corresponding to 50% of the cumulative weight in the particle size-weight distribution.

[0069] Also, in order to form a high specific gravity balance weight composition, a mixture of metal particles in powder form having different particle sizes in the range of 30 μm to 120 μm can be used. The tap density of such metal particles can be from 6.0 g / cm 3 to 10.0 g / cm 3 and preferably from 7.0 g / cm 3 to 10.0 g / cm 3 The apparent density of the metal particles can be from 4.0 g / cm 3 to 8.0 g / cm 3 and preferably from 5.0 g / cm 3 to 8.0 g / cm 3

[0070] Table 1 below shows the experimental data of measuring the packing density of stainless steel powder by particle size used as a filler. When filling polar rubber while combining stainless steel powders having particle sizes of 10 μm to 50 μm, 30 μm to 120 μm, and 120 μm to 150 μm respectively, it can be confirmed that when the stainless steel powder having a particle size of 30 μm to 120 μm is combined and filled, a high apparent density and tap density are realized.

[0071] [Table 1]

[0072] The balance weight composition may contain more than 350 phr and less than 1,750 phr of the metal particles, based on 100 parts by weight (phr) of the polar rubber, and preferably contains 500 phr to 1,580 phr.

[0073] If the content of the metal particles is 350 phr or less, the specific gravity will be excessively low, requiring a larger volume in the balance weight to achieve a specific gravity within the appropriate range, which may generate noise and vibration when applied to vehicle wheels. Furthermore, if the content of the metal particles is 1,750 phr or more, poor mixing and separation of metal particles may occur during the mixing of the composition and the manufacture of the balance weight, resulting in insufficient interfacial reactivity between the metal particles and the polar rubber, which may reduce the fatigue resistance to repeated bending.

[0074] plasticizer

[0075] In one embodiment, the balance weight composition may further contain a plasticizer. The plasticizer improves the miscibility and processability of the balance weight composition containing polar rubber, while simultaneously preventing aging of the balance weights manufactured using the composition and imparting flexibility.

[0076] The plasticizer may include one selected from the group consisting of paraffinic compounds, naphthenic compounds, olefinic compounds, aromatic compounds, and combinations thereof.

[0077] Specifically, as the plasticizer, aliphatic or aromatic oils or paraffinic waxes (linear, branched, or ring type) can be used, and exemplary, aromatic, naphthenic, or paraffinic mineral oil plasticizers (e.g., MES (hardness extracting solvide)) can be used. More specifically, products such as Shellflex 371 (Shell) and Synfluid 6cSt (Chevron) may be applied. In this case, the plasticizer added to the balance weight composition may be one that has a solubility parameter similar to that of the polar rubber contained in the balance weight composition.

[0078] The balance weight composition may contain more than 0 phr and up to 30 phr of the plasticizer, based on 100 parts by weight (phr) of the polar rubber. If the plasticizer content exceeds 30 phr, the mixing efficiency will decrease due to adhesion during mixing of the composition, and flow (wave pattern) will occur in the die portion of the extruder during extrusion molding, making it difficult to maintain the shape of the balance weight.

[0079] Other additives

[0080] In one embodiment, the system may further include any one selected from the group consisting of an acid acceptor, an antioxidant, a filler, and combinations thereof. The acid acceptor may include metal oxides, metal hydroxides, etc. The antioxidant may include diphenylamine derivatives, phenylenediamine derivatives, etc. The processing aid may include stearic acid, zinc oxide, etc. The filler may include carbon black, kaolin clay, talc, diatomaceous earth, etc.

[0081] In one embodiment, the balance weight composition according to the present invention may contain 1 phr to 2 phr of inorganic oxide, 0.8 phr to 2 phr of fatty acid, 5 phr to 30 phr of plasticizer, and 500 phr to 1,580 phr of stainless steel (SUS) powder, based on 100 parts by weight (phr) of polar rubber. When the balance weight composition satisfies the above numerical range, it may have excellent compoundability and bendability, high specific gravity, and well-balanced and excellent chemical resistance, including fuel resistance, ozone resistance, and weather resistance.

[0082] In one embodiment, the balance weight composition according to the present invention may not contain a crosslinking agent and a crosslinking accelerator.

[0083] Generally, balance weight compositions contain crosslinking agents and / or crosslinking accelerators, in which case sulfur (S) series crosslinking agents or peroxide series (DCP) crosslinking agents are used. In addition, metal oxide crosslinking agents such as magnesium-based and aluminum-based agents are also used. When a crosslinking agent is added to the composition, crosslinking points are formed by permanent chemical bonds between molecular chains, and a thermosetting material can be formed. Balance weights manufactured with such compositions can have improved mechanical strength, but they exhibit brittle properties, do not melt well when heated, or release toxic gases into the atmosphere when heated more intensely, making recycling difficult.

[0084] The balance weight composition according to the present invention has excellent mutual attraction and adhesion with metal particles, and since it uses polar rubber, which is a thermoplastic material, it does not need to contain separate crosslinking agents and crosslinking accelerators. This makes recycling even more advantageous by allowing scrap generated during the process to be put back into the process, or by recovering the balance weights manufactured with the balance weight composition and converting them back into the balance weight composition.

[0085] In one embodiment, the specific gravity of the balance weight composition according to the present invention may be 3.0 or higher. If the specific gravity of the balance weight composition is lower than 3.0, a larger amount of the composition must be used to make the weight of the balance weight produced with the composition equal to or greater than the required value, which may increase the overall volume of the balance weight.

[0086] On the other hand, according to another embodiment of the present invention, a balance weight can be provided obtained by compression molding the balance weight composition. Furthermore, the balance weight may be applied to a vehicle wheel. The components included in the balance weight and their weight ratios may be substantially similar to those included in the balance weight composition.

[0087] A method for extruding a balance weight composition can be a conventional method used in the art, which may include, for example, the steps of heating the balance weight composition to a predetermined temperature, extruding the heated result, and post-processing the extruded result.

[0088] The heating temperature in the extrusion molding process is between the glass transition temperature and the melting point of the polar rubber, and can be in a temperature range inside or outside the melting point.

[0089] The extrusion in the aforementioned extrusion molding may be carried out so as to form an extruded product of the desired shape. Post-processing in the aforementioned extrusion molding may include processes such as cutting the extruded product and printing the surface. The aforementioned extrusion molding may be carried out through an extruder that includes a hopper into which raw materials flow, a barrel communicating with the hopper and containing a fluid space for the raw materials, a stirring means for stirring and moving the raw materials in the fluid space, a heater for heating the fluid space, and an extrusion die communicating with the fluid space. In addition, a banbury, kneader, mixing roller, etc., may be applied to mix, blend, and disperse the balance weight composition before extrusion molding.

[0090] The balance weight can be applied to parts and components that require the above-described characteristics, and can be applied to the wheels of a vehicle. When applied as a wheel balance weight, it can be formed into a long, rollable strip, as shown in Figure 1. In addition, a separate film may be attached to one and / or other surfaces of the balance weight, and adhesive films and release films may also be attached.

[0091] The present invention will be described in detail below with reference to the following examples and comparative examples. However, the technical concept of the present invention will not be limited or restricted thereby. [Examples]

[0092] Example 1

[0093] A molded article according to Example 1 was produced by blending a composition containing 100 parts by weight (phr) of nitrile butadiene rubber, 2 phr of zinc oxide (an inorganic oxide), 1 phr of stearic acid (a fatty acid), 10 phr of naphthenic oil (a plasticizer), and 500 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm) through a Banbury mixer and extruding it through a heated extruder (Thermo SCIENTIFIC / HAAKE).

[0094] Example 2

[0095] A molded article according to Example 2 was manufactured using the same process as in Example 1, except that a composition was used that contained 3 phr of zinc oxide, 2 phr of stearic acid, 5 phr of naphthenic oil, and 1,200 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0096] Example 3

[0097] A molded article according to Example 3 was manufactured using the same process as in Example 1, except that a composition was used that contained 4 phr of zinc oxide, 1.5 phr of stearic acid, 20 phr of naphthenic oil, and 1,580 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0098] Example 4

[0099] A molded article according to Example 4 was manufactured using the same process as in Example 1, except that a composition was used that contained 1 phr of zinc oxide, 0.8 phr of stearic acid, 30 phr of naphthenic oil, and 900 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0100] Comparative Example 1

[0101] A molded article according to Comparative Example 1 was manufactured using the same process as in Example 1, except that a composition was used that contained 0.5 phr of zinc oxide, 2 phr of stearic acid, 10 phr of naphthenic oil, and 500 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0102] Comparative Example 2

[0103] A molded article according to Comparative Example 2 was manufactured using the same process as in Example 1, except that a composition was used that contained 5 phr of zinc oxide, 0.3 phr of stearic acid, 20 phr of naphthenic oil, and 1,700 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0104] Comparative Example 3

[0105] A molded article according to Comparative Example 3 was manufactured using the same process as in Example 1, except that a composition was used that contained 2 phr of zinc oxide, 6 phr of stearic acid, and 1,600 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm) based on 100 parts by weight (phr) of nitrile butadiene rubber, and did not contain a plasticizer.

[0106] Comparative Example 4

[0107] A molded article according to Comparative Example 4 was manufactured using the same process as in Example 1, except that a composition was used that contained 1 phr of zinc oxide, 1 phr of stearic acid, 35 phr of naphthenic oil, and 1,400 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0108] Comparative Example 5

[0109] A molded article according to Comparative Example 5 was manufactured using the same process as in Example 1, except that a composition was used that contained 2 phr of zinc oxide, 1.5 phr of stearic acid, and 350 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm) based on 100 parts by weight (phr) of nitrile butadiene rubber, and did not contain a plasticizer.

[0110] Comparative Example 6

[0111] A molded article according to Comparative Example 6 was manufactured using the same process as in Example 1, except that a composition was used that contained 4 phr of zinc oxide, 1 phr of stearic acid, 10 phr of naphthenic oil, and 1,750 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0112] Comparative Example 7

[0113] A molded article according to Comparative Example 7 was manufactured using the same process as in Example 1, except that a composition was used that contained 1 phr of zinc oxide, 1 phr of stearic acid, 10 phr of naphthenic oil, and 1,800 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0114] Comparative Example 8

[0115] A molded article according to Comparative Example 8 was manufactured using the same process as in Example 1, except that a composition was used that contained 55 phr of zinc oxide, 1.5 phr of stearic acid, 30 phr of naphthenic oil, and 1,550 phr of ferritic stainless steel powder (D50: 30 μm to 120 μm), based on 100 parts by weight (phr) of nitrile butadiene rubber.

[0116] Reference example 9

[0117] A molded article according to Reference Example 9 was manufactured through the same process as in Example 1, except that a composition containing natural rubber (NR), which is a nonpolar rubber, was used instead of nitrile butadiene rubber, which is a polar rubber.

[0118] The compositions of the molded articles relating to Examples 1 to 4 and Comparative Examples 1 to 8 are shown in Table 2 below.

[0119] [Table 2]

[0120] Experimental Example 1 - Compatibility Measurement

[0121] To investigate the blendability of the balance weight compositions according to the present invention, each composition was blended through a Banbury mixer, and the blendability of the compositions was observed visually. The appearance of the molded bodies extruded through a heated extruder was also observed visually. The results are shown in Table 3 below. Here, if the metal particle powder was separated or mixing was difficult, it was judged as "defective".

[0122] Experimental Example 2 - Measurement of Physical Properties

[0123] To investigate the various physical properties of molded articles produced with the balance weight composition according to the present invention, bendability, specific gravity, fuel resistance, ozone resistance, and weather resistance tests were conducted using the following method. The results are shown in Table 3 below.

[0124] 1) Evaluation of flexibility

[0125] The molded body was cooled to room temperature, and test specimens were obtained by cutting them to a size of 23 mm wide, 100 mm long, and 4.5 mm thick. At a temperature of 23°C and a relative humidity of 50%, the molded body was bent for 2 seconds so that the angle between one end and the other end was 45° relative to the longitudinal direction of the body, and then returned to its original state. This process was considered one unit and repeated until a crack occurred. Some of the results for the bendability evaluation are shown in Figure 2. Here, if a crack or break was observed with the naked eye, it was judged as a "crack," and the number of times the crack occurred is also indicated.

[0126] 2) Specific gravity

[0127] The molded body was cooled to room temperature, and test specimens were obtained by cutting them to a size of 23 mm wide, 100 mm long, and 4.5 mm thick. The specific gravity was measured using a hydrometer (ALFA MIRAGE, electronic densimeter) at 25°C and 1 atmosphere without applying any external force.

[0128] 3) Fuel resistance evaluation

[0129] Following the MS268-05 standard of the Katri Institute of Testing and Research, test specimens were obtained by cooling the molded body to room temperature and then cutting it into pieces measuring 20 mm wide, 20 mm long, and 4.5 mm thick. These specimens were then immersed in gasoline fuel for 2 hours, removed, and visually inspected for any breakage, cracking, whitening, rusting, etc. If no swelling or delamination was observed, the specimen was judged to be "good."

[0130] 4) Ozone resistance evaluation

[0131] Following the MS269-03 standard of the Katri Institute of Testing and Research, test specimens were obtained by cooling the molded body to room temperature and then cutting it into pieces measuring 20 mm wide, 20 mm long, and 4.5 mm thick. These specimens were then exposed to ozone at a concentration of 50 pphm at 40°C for 72 hours, after which the surface was analyzed. Some of the results for the ozone resistance evaluation are shown in Figure 4. Here, the result was judged as "good" if no surface cracks or fracture phenomena were observed.

[0132] 5) Weather resistance evaluation

[0133] Based on the MS210-06 standard for visible parts from Katri Testing and Research Institute, test specimens were obtained by cooling the molded body to room temperature and then cutting it into pieces measuring 20mm wide, 20mm long, and 4.5mm thick, and then exposing them to 340nm ultraviolet light at 0.75W / m². 2 One cycle consists of 120 minutes of irradiation followed by 60 minutes of water spraying in darkness, resulting in a UV irradiation dose of 2500 kJ / m³. 2 After processing until the desired result was reached, discoloration, color transfer, and whitening were measured. Some of the results for the weather resistance evaluation are shown in Figure 3. Here, if no discoloration, color transfer, or whitening occurred, it was judged as "satisfactory".

[0134] [Table 3]

[0135] Referring to Table 3 and Figure 2, Examples 1 to 4 demonstrated good compositional compatibility (mixing / extrusion appearance), and exhibited excellent balance of flexibility, fuel resistance, ozone resistance, and weather resistance. Furthermore, since the specific gravity of the compositions exceeded 3.0, it was confirmed that they possessed a specific gravity suitable for use as balance weights.

[0136] Based on the results of Comparative Examples 1 and 8, in which the content of zinc oxide added as an inorganic oxide activator was adjusted, it was confirmed that in Comparative Example 1, powder separation was observed in the compatibility measurement results. This is presumed to be due to an excessively low content of zinc oxide added as an inorganic oxide activator.

[0137] Furthermore, in the case of Comparative Example 8, powder aggregation was observed in the compounding properties measurement results, and cracks were confirmed to have occurred after 40 bending tests. This is presumed to be due to the excessively high inorganic oxide content, which caused aggregation of metal particle powder and reduced fatigue resistance due to decreased dispersibility.

[0138] Based on the results of Comparative Examples 2 and 3, in which the content of stearic acid added as an activating fatty acid was adjusted, in Comparative Example 2, powder separation was observed in the compatibility measurement results, and as can be seen in Figure 2, cracking was observed after 40 turns in the bending test results. This is presumed to be because the content of stearic acid added as an activating fatty acid was excessively low, making it difficult to ensure adequate filling of metal particles. As a result, it became difficult to form effective adhesion between the polar rubber and the metal particles, leading to powder separation and cracking of the material.

[0139] In the case of Comparative Example 3, although the blendability was good, discoloration and color transfer were observed in the weather resistance measurement results. As can be seen in Figure 3, cracks were observed when the test piece was bent after the weather resistance test. This is presumed to be due to the accumulation of unreacted stearic acid, which caused powder separation during mixing, resulting in discoloration and color transfer.

[0140] In Comparative Example 4, the results of the compounding tests showed that adhesion occurred, and flow occurred in the die section of the extruder, making it difficult to maintain the shape of the balance weight. Furthermore, the weather resistance tests showed discoloration and color transfer. This is presumed to be due to the inclusion of an excessive amount of plasticizer, which resulted in an excessively low viscosity of the composition.

[0141] In the case of Comparative Example 5, there were no problems with the compounding measurement results, but the specific gravity was measured at 2.82, confirming that it should be 3.0 or less. This is presumed to be due to the inclusion of excessively small amounts of metal particles with high specific gravity. If the composition of Comparative Example 5 is applied to an actual product, its volume will be larger than that of each example of the same weight, which may increase noise during operation.

[0142] In Comparative Example 6, the mixing performance measurement results showed separation of the metal particle powder, and the bending test results showed cracking after 40 cycles. Similarly, in Comparative Example 7, the mixing performance measurement results showed separation of the metal particle powder, and the bending test results showed cracking after 35 cycles. This is presumed to be due to the excessively high content of metal particles in the composition, which made mixing between the polar rubber and the metal particle powder difficult. Furthermore, it is predicted that the adhesive performance between the polar rubber and the metal particles was poor, and that cracking occurred before 50 cycles during the 45° repeated bending evaluation.

[0143] On the other hand, in the case of Reference Example 9, which uses natural rubber, a nonpolar rubber, as can be seen in Figure 4, the ozone resistance test results confirmed the occurrence of microcracks.

[0144] Although embodiments of the present invention have been described above, a person with ordinary skill in the art can modify and change the present invention in various ways by adding, changing, deleting, or adding components, without departing from the spirit of the invention as described in the claims, and this can also be said to be within the scope of the rights of the present invention.

Claims

1. A balance weight composition comprising polar rubber; an activator; and metal particles, Based on 100 parts by weight (phr) of the aforementioned polar rubber, The activator in an amount of 1.5 phr or more and less than 60 phr; and The aforementioned metal particles exceeding 350 phr but less than 1,750 phr; Balance weight composition.

2. The aforementioned polar rubber is The balance weight composition according to claim 1, comprising any one selected from the group consisting of nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (H-NBR), chloroprene rubber (CR), and combinations thereof.

3. The nitrile butadiene rubber is The balance weight composition according to claim 2, comprising a Mooney viscosity (ML1+4) of 40 to 75 at 100°C.

4. The aforementioned hydrogenated nitrile butadiene rubber is The balance weight composition according to claim 2, comprising a composition having a Mooney viscosity (ML1+4) of 55 to 75 at 100°C.

5. The chloroprene rubber mentioned above is The balance weight composition according to claim 2, comprising a Mooney viscosity (ML1+4) of 30 to 60 at 100°C.

6. The aforementioned activator is The balance weight composition according to claim 1, comprising one selected from inorganic oxides, fatty acids, and combinations thereof.

7. The aforementioned inorganic oxide is Zinc oxide (ZnO), tin oxide (SnO) ２ ), aluminum oxide (Al ２ O ３ ), zirconium oxide (ZrO ２ The balance weight composition according to claim 6, comprising any one selected from the group consisting of ) and combinations thereof.

8. The aforementioned fatty acids are selected from saturated fatty acids and unsaturated fatty acids. The saturated fatty acid includes one selected from the group consisting of stearic acid, caprylic acid, lauric acid, myristic acid, arachidic acid, and combinations thereof. The balance weight composition according to claim 6, wherein the unsaturated fatty acid comprises one selected from the group consisting of oleic acid, elaidic acid, linoleic acid, ricinoleic acid, and combinations thereof.

9. The inorganic oxides 1 phr or more and less than 55 phr; and The balance weight composition according to claim 6, comprising 0.5 phr to 5 phr of the aforementioned fatty acid.

10. The aforementioned metal particles are The balance weight composition according to claim 1, comprising one selected from the group consisting of austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and combinations thereof.

11. The balance weight composition according to claim 1, wherein the average particle size (D50) of the metal particles is 1 μm to 150 μm.

12. The metal particles have a particle size of 30 μm to 120 μm. The tap density of the aforementioned metal particles is 6.0 g / cm³. ３ ~10.0g / cm ３ in, The apparent density of the aforementioned metal particles is 4.0 g / cm³. ３ ~8.0g / cm ３ The balance weight composition according to claim 1.

13. The balance weight composition according to claim 1, further comprising a plasticizer.

14. The aforementioned plasticizer is The balance weight composition according to claim 13, comprising one selected from the group consisting of paraffinic compounds, naphthenic compounds, olefinic compounds, aromatic compounds, and combinations thereof.

15. The balance weight composition according to claim 13, comprising more than 0 phr of plasticizer and 30 phr or less.

16. The balance weight composition according to claim 1, further comprising one selected from the group consisting of acid receptors, anti-aging agents, fillers, and combinations thereof.

17. Based on 100 parts by weight (phr) of the aforementioned polar rubber, Inorganic oxide 1 phr to 2 phr; Fatty acids 0.8 phr to 2 phr; plasticizers 5 phr to 30 phr; and The balance weight composition according to claim 1, comprising 500 phr to 1,580 phr of the aforementioned metal particles.

18. The balance weight composition according to claim 1, which does not contain a crosslinking agent or a crosslinking accelerator.

19. A balance weight obtained by compression molding a balance weight composition according to any one of claims 1 to 18.

20. A balance weight according to claim 19, applicable to a vehicle wheel.

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