KR102721742B1 - Epdm rubber compounds with surface embossing efect of glass run corner molding using uhmwpp and glass run for vehicle by using the same - Google Patents

Abstract

The present embodiments relate to an EPDM rubber composition having an embossing effect on the surface of a glass run corner molded part using UHMWPP, and an automotive glass run product using the same. Specifically, an EPDM rubber composition having an embossing effect on the surface of a glass run corner molded part using UHMWPP according to one embodiment includes ethylene propylene diene monomer (EPDM), a reinforcing agent, a softening agent, a high-functional olefin resin, a vulcanization activator, a processing aid, an anti-foaming agent, a vulcanizing agent, and a vulcanization accelerator, wherein the high-functional olefin resin may have a weight average molecular weight (Mw) of 500,000 to 2,500,000 as measured by gel permeation chromatography (GPC).

Description

EPDM rubber composition with surface embossing effect of glass run corner molding using UHMWPP and glass run product for vehicle using the same {EPDM RUBBER COMPOUNDS WITH SURFACE EMBOSSING EFECT OF GLASS RUN CORNER MOLDING USING UHMWPP AND GLASS RUN FOR VEHICLE BY USING THE SAME}

The present examples relate to an EPDM rubber composition having a surface embossing effect for a glass run corner molding part using UHMWPP, and more specifically, to a rubber composition used for a corner molding part of a glass run channel product, which is a sealing part for automobiles.

Glass Run Channel is a sealing component that is installed on the edge of the window of a car door to guide (prevent detachment) the window when it is raised/lowered and to block wind noise, rainwater, noise, dust, etc. that may enter the interior from the outside. Therefore, when considering the installation location of the product, it is a component that must satisfy the characteristics of both the exterior and interior materials because it is installed on the boundary between the interior and exterior materials of the car.

Recently, there has been a trend toward demanding emotional quality even in functional parts, and for glass run products as well, uniqueness, which is an emotional requirement for interior materials, is required as an important exterior quality.

In particular, glass run products include an extruded rubber profile formed by an extrusion method and a corner formed section in which the extruded profile is formed to fit the corner of an automobile window. At this time, a different feeling is generated due to the difference in the forming method.

However, this exotic feel has the problem of significantly reducing marketability because it lowers the product's appearance quality and aesthetics.

In this embodiment, in order to improve the appearance quality of the corner molding of a glass run channel (hereinafter referred to as glass run) product, which is an automobile component, an EPDM rubber composition having an embossing effect on the surface of a glass run corner molding using UHMWPP that can minimize the discoloration between the extruded cross-section constituting the glass run component and the corner molding, and an automobile glass run product using the same are provided.

An EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP according to one embodiment comprises ethylene propylene diene monomer (EPDM), a reinforcing agent, a softening agent, a high-functional olefin resin, a vulcanization activator, an anti-foaming agent, a vulcanizing agent, and a vulcanization accelerator, wherein the high-functional olefin resin may have a weight average molecular weight (Mw) of 500,000 to 2,500,000 as measured by gel permeation chromatography (GPC).

The above-mentioned high-functionality olefin resin may have a melting point measured by differential scanning calorimetry (DSC) in the range of 110°C to 200°C.

The above-mentioned high-functionality olefin resin may have a melt index (MI) of 0.05 to 20 g/10 min as measured by ASTM D1238.

The above high-functionality olefin resin may include ultra high molecular weight polypropylene (UHMWPP).

The content of the above high-functionality olefin resin may be in the range of 6 parts by weight to 24 parts by weight based on the weight part of the ethylene propylene diene monomer (EPDM).

The above ethylene propylene diene monomer (EPDM) may have a patterned viscosity (ML1+4, 125°C) value of 60 mu or less.

The above ethylene propylene diene monomer (EPDM) may have an ethylidene norbornene (ENB) content of 7 wt% or more and an ethylene content of 60.0 wt% or less.

The above rubber composition may include 75 to 100 parts by weight of the reinforcing agent, 35 to 45 parts by weight of the softener, 5 to 10 parts by weight of the vulcanization activator, 2 to 5 parts by weight of the processing aid, 3 to 5 parts by weight of the anti-foaming agent, 1 to 2 parts by weight of the vulcanizing agent, and 2 to 5 parts by weight of the vulcanization accelerator, based on 100 parts by weight of the ethylene propylene diene monomer (EPDM).

The above reinforcing agent may include at least one of carbon black and silica.

The above reinforcing agent may have an average particle diameter in the range of 40 to 48 nm.

The above vulcanization activator may include zinc oxide and stearic acid.

The above processing agent may include polyethylene glycol (PEG#4000: molecular weight 4,000) and a metal salt.

The above-mentioned vulcanization accelerator may include at least one of MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), ZnBDC (zinc di-n-butyl dithiocarbamate), TMTD (tetramethylthiuram disulfide), and CBS (N-cyclohexyl-2-benzothiazyl sulfonamide).

According to another embodiment, an automotive glass run product may be manufactured using an EPDM rubber composition having a surface embossing effect of a glass run corner molding portion using the UHMWPP.

The surface roughness of the corner forming part of the above glass run product can be 1.0 Ra or higher.

An EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP according to one embodiment is used for a corner joint of a glass run product. Specifically, by being used for a joint between an extruded section (Extruded Rubber Profile) and an extruded section, the product can be significantly improved in marketability by minimizing the discoloration of the appearance of a product having a difference in molding method.

Currently, the corner molding part of glass run products is generally manufactured using the surface corrosion method of the transfer mold. However, this surface corrosion method has problems such as the wear of the corrosion surface and the absorption of rubber oil vapor on the surface during the product manufacturing process, which reduces the appearance quality of the product.

However, when manufacturing an automotive glass run product using an EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP of the present embodiment, the appearance quality of the product can be improved while ensuring uniformity of quality.

Figure 1 is a schematic diagram of a device for exemplarily explaining a transfer-type forming method.
FIG. 2 shows surface photographs of specimens manufactured using rubber compositions manufactured according to Example 1 and Comparative Examples 1 and 2.
Figure 3 shows the equipment used to measure surface roughness in this example.
Figures 4a and 4b show the poor dispersion state of the rubber composition of Reference Example 2.
Figure 5 shows surface photographs of specimens manufactured using rubber compositions manufactured according to Reference Example 1, Example 2, and Example 3.
Figure 6a shows a sample to which an existing glass run corner joint rubber has been applied.
Fig. 6b shows a sample using a glass run corner joint rubber manufactured using a rubber composition manufactured according to Example 3.

The terms first, second, and third, etc. are used to describe, but are not limited to, various parts, components, regions, layers, and/or sections. These terms are only used to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms include the plural forms as well, unless the context clearly dictates otherwise. The word "comprising," as used herein, specifies particular features, regions, integers, steps, operations, elements, and/or components, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and/or components.

When a part is referred to as being "on" or "on" another part, it may be directly on or above the other part, or there may be other parts intervening. In contrast, when a part is referred to as being "directly on" another part, there are no other parts intervening.

Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.

An EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP according to one embodiment may include ethylene propylene diene monomer (EPDM), a reinforcing agent, a softening agent, a high-functional olefin resin, a vulcanization activator, an anti-foaming agent, a vulcanizing agent, and a vulcanization accelerator.

Hereinafter, each component constituting the EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP according to the present invention will be described in more detail.

(1) High-performance olefin resin

In the EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP according to the present embodiment, the high-functionality olefin resin is for securing a surface corrosion effect.

Specifically, the high-functionality olefin resin may have a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) in the range of 500,000 to 2,500,000, more specifically, in the range of 2,500,000. When the weight average molecular weight of the high-functionality olefin resin satisfies the above range, a glass run product having excellent tensile strength and wear resistance can be realized.

In addition, the high-functionality olefin resin may have a melting point measured by differential scanning calorimetry (DSC) in the range of 110°C to 200°C, more specifically, 130°C to 180°C or 150°C to 175°C.

The above-mentioned high-functionality olefin resin may have a melt index (MI) measured by ASTM D1238 of 0.05 to 20 g/10 min, more specifically 0.05 to 5 g/10 min or 0.5 to 5 g/10 min.

When the melting point and melting index satisfy the above ranges, a glass run product having excellent tensile strength and wear resistance can be realized. In addition, it is very advantageous for securing an embossing effect in a glass run product to which the rubber composition of the present embodiment is applied. In this way, when the embossing effect, that is, a surface roughness of a certain level or higher, is secured, the discoloration of the extruded cross-section and corner-formed portion of the glass run product can be minimized.

In this embodiment, the high-functionality olefin resin may include, for example, ultra high molecular weight polypropylene (UHMWPP).

In addition, the content of the high-functionality olefin resin may be in the range of 6 parts by weight to 24 parts by weight, more specifically, 10 parts by weight to 20 parts by weight, based on the weight part of the ethylene propylene diene monomer (EPDM). When the content of the high-functionality olefin resin is less than 6 parts by weight, there is a problem of insufficient embossing effect, and when the content of the high-functionality olefin resin exceeds 24 parts by weight, poor dispersion may occur in the mixing process for producing a high-capacity composition.

In some cases, LDPE is used to reinforce rigidity when manufacturing rubber compositions. This is to incorporate the high hardness and physical properties of poly-olefin elastomer (POE: Poly Olefin Elastomer) into rubber compounding.

However, in general, when high hardness rubber of EPDM compound, i.e. product properties of Shore 85A or higher, is required, it is very difficult to secure the properties using EPDM and carbon black.

In particular, when increasing the hardness by increasing the amount of carbon black, the Mooney Viscosity of EPDM also increases, which may significantly reduce the processability and moldability.

In this example, instead of using POE for the stiffness reinforcing effect, a high molecular weight POE product was used. This is because the shape retention ability of the high molecular weight POE resin was improved during the rubber molding process. This is to secure an embossing (surface roughness) effect by using a high molecular weight and high MP (Melting Point) product as mentioned above.

Unlike general-purpose polypropylene (P.P: Poly Propylene), UHMWPP material is difficult to process using the existing P.P polymer material processing method due to the maximum molecular weight and high viscosity. Therefore, a new method is needed for rubber compounding.

That is, due to the M.P characteristics according to the high molecular weight, the aforementioned LDPE achieves plasticization through sufficient softening in rubber compounding, but UHMWPP exists in a state where the shape of UHMWPP itself is maintained in the rubber compounding.

This UHMWPP maintains its particle shape at high molding temperatures and can maintain its shape even after vulcanization of the corner molded part of a glass run product, thereby producing a surface embossing effect.

(2) Ethylene propylene diene monomer (EPDM)

Glass run is a type of sealing component for automobiles and requires weather ability. Therefore, in order to secure high weather ability, EPDM, which has excellent weather ability among synthetic rubbers, is used, and this is common not only among domestic but also global weather strip manufacturers.

In the present invention, EPDM was also used as a base polymer.

In general, the corner forming part of glass run products is done through transfer molding, and transfer molding requires excellent flow of rubber. Therefore, products with relatively low pattern viscosity are preferred.

Among the structural factors of EPDM, various characteristics are exhibited depending on the Mooney Viscosity, ENB content, and ethylene/propylene content ratio (EP Ratio).

The ethylene propylene diene monomer (EPDM) used in this embodiment preferably has a pattern viscosity (ML1+4, 125°C) of 60 mu or less, and more specifically, 20 mu or more and 30 mu or less. When the pattern viscosity of the EPDM satisfies the above range, the low pattern viscosity of the EPDM rubber composition having an embossing effect on the surface of a glass run corner molding part using UHMWPP according to one embodiment can be secured, and accordingly, the molding workability of a glass run product is excellent due to excellent rubber flow, thereby improving productivity and ensuring uniform product quality.

In addition, ENB, 1, 4-Hexadiene, DCPD (Dicyclopentadiene), etc. are used as the third component of EPDM, and in this example, EPDM using ethylene norbornene (ENB) was used. This is advantageous in securing productivity due to rapid crosslinking performance as well as crosslinking properties and securing high physical properties of the product.

Specifically, in the present embodiment, the ethylene propylene diene monomer (EPDM) preferably has an ethylidene norbornene (ENB) content of 7 wt% or more, more specifically, 7.5 to 9.0 wt%, based on the EPDM. When the ENB content included in the EPDM satisfies the above range, the vulcanization reaction is activated, and the productivity of the glass run product can be improved.

In addition, the ethylene propylene diene monomer (EPDM) preferably has an ethylene content of 60.0 wt% or less, more specifically 55 to 60 wt%, based on EPDM. When the ethylene content included in the EPDM satisfies the above range, the crystallinity is excellent, and thus, when a product is manufactured using the rubber composition of the present embodiment, the automobile assembly workability is excellent.

(3) Reinforcement

In this embodiment, the reinforcing agent may include at least one of carbon black and silica.

Among these, the above carbon black is classified into N100 to N900 according to ASTM standards based on particle size. However, for products requiring high durability such as tires, products with small particle sizes of N200 to N300 are generally used, and for products requiring high dynamic properties, products with N700 to N900 are generally used.

In this embodiment, it is preferable to use N550, i.e., FEF (Fast Extrusion Furnace) carbon black, as the reinforcing agent. This is because the reinforcing agent is advantageous in terms of securing flowability in the molding process and securing rigidity of the glass run product.

In addition, the reinforcing agent may be included in a range of 75 to 100 parts by weight based on 100 parts by weight of ethylene propylene diene monomer (EPDM). If the content of the reinforcing agent is less than 75 parts by weight, the mechanical properties may be significantly reduced.

In addition, when the reinforcing agent content exceeds 100 parts by weight, transfer molding becomes difficult because high hardness and reduced flowability in the extrusion process occur.

(4) Softener

Glass run products are functional parts, but they also require high emotional quality, i.e., appearance quality. Therefore, the softener used in this example may cause emotional quality issues such as discoloration and color change, so paraffin oil, such as rubber compounding oil (process oil), which is relatively excellent in discoloration, color change, and heat aging, can be used.

In this embodiment, the softener may be included in an amount of 35 parts by weight to 45 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer (EPDM).

When the content of the softener is less than 35 parts by weight, the dispersibility and processability are poor during the manufacture of the rubber composition, and the hardness increases, making the molding process difficult.

In addition, if the softener content exceeds 45 parts by weight, the dispersibility is poor, and the physical properties are deteriorated due to the decrease in hardness, which may result in a decrease in sealing performance.

In addition, calcium carbonate may be used as needed to improve appearance quality and secure cost competitiveness, and may be used in an amount ranging from 0 to 20 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer (EPDM). If the content of calcium carbonate exceeds 20 parts by weight, poor dispersion and deterioration of physical properties may occur.

However, calcium carbonate was not used in this example.

(5) Curing activator and processing aid

A vulcanization activator is a rubber raw material that improves the accelerating ability of a vulcanization accelerator.

In this embodiment, zinc oxide (ZnO), a metal oxide, and stearic acid, a fatty acid, are used as vulcanization activators.

Processing aids are added in small amounts to rubber compounds to improve the processability of rubber raw materials, such as mixing and dispersing them, and polyethylene glycol (PEG#4000: molecular weight 4,000) and metal salts are used to ensure smooth molding processes through lubricating action.

The above-mentioned vulcanization activator may be included in an amount of 5 to 10 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer (EPDM).

The hardening agent may contain 2 to 5 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer (EPDM).

If the content of the vulcanizing activator and processing aid exceeds the above range, a whitening phenomenon (also called blooming) may occur, which may lower the appearance quality as unreacted fatty acid salts migrate to the surface. This is a critical quality-lowering factor for glass run products that require excellent appearance quality.

(6) Anti-foaming agent

The moisture that may exist inside the rubber evaporates during the molding process, forming pores inside. The pores formed inside the product may affect the outside in the form of protrusions, and in some cases, durability may be reduced. CaO is used as an anti-foaming agent to remove the moisture that causes the pores in advance. It must be used especially in the extrusion process.

_H2O + CaO → Ca(OH) ₂

Moisture and calcium oxide react to produce calcium hydroxide, which has the same effect as an inorganic filler dispersed within rubber and thus can suppress the formation of pores.

The above-mentioned anti-foaming agent can be used in an amount ranging from 3 parts by weight to 5 parts by weight based on 100 parts by weight of the above-mentioned ethylene propylene diene monomer (EPDM).

(7) Vulcanizer

In general, the crosslinking method of the rubber composition includes, for example, sulfur crosslinking, peroxide crosslinking, and resin crosslinking, but in the present embodiment, it can be manufactured by a sulfur crosslinking method.

Sulfur crosslinking is formed when sulfur is combined with the double bond structure of the base polymer, and sulfur must be used to provide elasticity to rubber compounds.

At this time, the vulcanizing agent used, sulfur, is composed of a cyclic S8 molecular structure, and at 159℃, the cyclic structure is converted into a chain structure, activating the vulcanization reaction in which the viscous force of the rubber is converted into elastic force.

Also, when sulfur is added to rubber and heat is applied, the sulfur causes a chemical reaction to form individual polymer chains into a three-dimensional network structure, which is called vulcanization. At this time, if a vulcanization accelerator is used, the vulcanization speed can be increased and efficient vulcanization can be performed at a relatively low temperature.

The above-mentioned vulcanizing agent may be included in an amount of 1 to 2 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer (EPDM). When the content of the vulcanizing agent satisfies the above-mentioned range, vulcanization can be performed efficiently.

(8) Vulcanization accelerator

A vulcanization accelerator may be used to promote the above vulcanization reaction.

The above-mentioned vulcanization accelerator may include at least one of MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), ZnBDC (zinc di-n-butyl dithiocarbamate), TMTD (tetramethylthiuram disulfide), and CBS (N-cyclohexyl-2-benzothiazyl sulfonamide).

The above MBT (2-mercaptobenzothiazole) generally has low contamination, exhibits smooth vulcanization, and has excellent aging resistance and physical properties. Its acceleration ability is a semi-acceleration ability.

MBTS (dibenzothiazyl disulfide) has similar performance to MBS, but it tends to have a slower initial vulcanization speed, which is advantageous for securing stability in molding operations.

In addition, ZnBDC (zinc di-n-butyl dithiocarbamate) has a very strong promoting ability and affects the activation of MBT/MBTS. It is known to have very little or no contamination.

TMTD (tetramethylthiuram disulfide) is called a super accelerator because it has a very strong vulcanization accelerator ability, is non-polluting, and can secure high tensile strength and modulus.

CBS (N-cyclohexyl-2-benzothiazyl sulfonamide) is a curing accelerator that slows down the initial curing speed and is advantageous in securing the initial flowability of transfer molding.

The above-mentioned vulcanization accelerator may be included in an amount of 2 to 5 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer (EPDM).

That is, in the present embodiment, the EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP may include, based on 100 parts by weight of the ethylene propylene diene monomer (EPDM), 75 to 100 parts by weight of the reinforcing agent, 35 to 45 parts by weight of the softener, 5 to 10 parts by weight of the vulcanization activator, 2 to 5 parts by weight of the processing aid, 3 to 5 parts by weight of the anti-foaming agent, 1 to 2 parts by weight of the vulcanizing agent, and 2 to 5 parts by weight of the vulcanization accelerator.

An EPDM rubber composition having an embossing effect on a surface of a glass run corner molded part using UHMWPP according to one embodiment can secure excellent tensile strength and wear resistance because it includes the above-described high-functionality olefin resin. In addition, since an embossing effect can be implemented in a glass run product, the difference in color between an extrusion section and a corner molded part can be minimized, thereby securing excellent appearance quality and uniformity of appearance quality.

According to another embodiment, an automotive glass run product can be provided manufactured using an EPDM rubber composition having a surface embossing effect of a glass run corner molding using the aforementioned UHMWPP.

It is preferable that the surface roughness of the corner forming part of the above glass run product be 1.0 Ra or higher. When the surface roughness is 1.0 Ra or higher, the discoloration of the extruded cross-section can be minimized, thereby ensuring excellent appearance quality of the product.

At this time, the corner molding of glass run products is generally produced by transfer molding.

Transfer molding is a method used when it is difficult to manufacture with an injection mold using a compression mold. Rubber is injected into the pot at the top of the upper mold and the upper and lower molds are closed with force to form the glass run corners.

It is generally applied in cases where dimensional accuracy is required for small products.

This method is widely used because it is suitable for the glass run corner molding part of automobile parts where dimensional stability is of the utmost importance. Therefore, it is most important that the weight of the rubber being injected is kept constant. If the rubber weight is large, the weight overflows from the inside of the molding space to the outside, causing the contact area with the extrusion section to be pushed, and if the input weight is small, the molding is not completed.

Figure 1 is a schematic diagram of a device for exemplarily explaining a transfer-type forming method. The transfer-type forming method is the most commonly used method for manufacturing glass run corner forming parts, and almost all glass runs are manufactured using the transfer-type forming method.

Referring to Figure 1, a specific weight of rubber is injected into a hole at the top of the mold called a POT, and as the upper mold mounted on the press is lowered, the injection rod is pressed into the hole, and the injected rubber is injected into the glass run space, thereby forming the mold.

The mold temperature is set to the range of 180 to 200°C, and the vulcanization time is maintained for approximately 2 minutes (120 seconds) to 3 minutes (180 seconds) depending on the vulcanization characteristics of the rubber material in the injected state.

Depending on the size of the molded part, a curing time of 4 to 5 minutes may be required.

Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples, and the present invention is not limited thereby, and the present invention is defined only by the scope of the claims described below.

Experimental Example 1

Rubber compositions according to Examples 1 and 2 and Comparative Examples 1 and 2 were prepared by mixing in the composition ratios described in Table 1 below.

Specifically, the mixing process for each rubber composition was performed in a Banbury Mixer for CMB rubber and in a Kneader for FMB rubber.

In addition, the EPDM polymer used in the CMB manufacturing was KEP-330 (Kumho Polychem), the carbon black was HS-45 from Orion Engineering Carbons, and additionally, ZnO (zinc oxide), Stearic Acid, and PEG#4000 (Poly Ethylene Glycol MW 4000) were used as vulcanization activators and processing aids. Specific information on the EPDM polymer used in this example is shown in Table 2 below.

The softener used was a paraffin-based rubber compounding oil.

Since the moisture content inside the rubber is a factor that can form pores inside the molded product, to prevent this, CaO (Calcium Oxide) was added so that moisture could be removed in advance as shown below.

CaO(calcium oxide) + _H2O (water) → Ca(OH) ₂

Additionally, a processing aid (process acid) was used to secure molding stability of the glass run corner. The processing aid is a mixture of fatty acid derivates (mainly zinc soaps), and was used because it is efficient in filling every corner of the molding part with high flowability when the rubber composition is filled into the molding.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 CMB Polymer EPDM 100 100 100 100 Reinforcement Carbon Black 85 90 85 85 Softener Process Oil 40 40 40 40 High functionality
Olefin
profit LDPE 　 　 10 　 UHMWPE 　 　 　 10 UHMWPP 10 　 　 　 vulcanization activator
& Processing preparation Zinc Oxide 8 8 8 8 Stearic Acid 1.5 1.5 1.5 1.5 PEG#4000 2 2 2 2 Process Aid 2 2 2 2 Anti-foaming agent Calcium Oxide 5 5 5 5 CMB Subtotal 253.5 248.5 253.5 253.5 FMB Emperor Sulfur 1.5 1.5 1.5 1.5 Vulcanization accelerator Accelerator MBT 0.7 0.7 0.7 0.7 Accelerator MBTS 0.3 0.3 0.3 0.3 Accelerator ZnBDC 1 1 1 1 Accelerator TMTD 0.5 0.5 0.5 0.5 Accelerator CBS 1.2 1.2 1.2 1.2 Total (CMB + FMB) 258.7 253.7 258.7 258.7

division KEP-330 Mooney Viscosity
(ML1+4,125℃) 28mu Ethylene Cont.(%) 57% ^3rd Monomer type
& Cont.(%) ENB (7.9%)

The chemical names and chemical formulas of the vulcanization accelerators in Table 1 above are as follows.

MBT: 2-Mercaptobenzothiazole (C ₇ H ₅ NS ₂ )

MBTS: Mercaptobenzothiazole disulfide (C ₁₄ H ₈ N ₂ S ₄ )

ZnBDC: Zinc dibutyl dithiocarbamate ([(C ₄ H ₉ ) ₂ NCS ₂ ] ₂ Zn)

TMTD: Tetramethyl thiuram disulfide ([(CH ₃ ) ₂ NCS ₂ -] ₂ )

CBS: N-cyclohexyl-2-benzothiazylesulfenamide (C ₁₃ H ₁₆ N ₂ S ₂ )

The manufacturing process of the EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP of this example can be largely divided into the CMB (Carbon Master Batch) and FMB (Final Master Batch) processes.

The manufacturing process of CMB rubber is a process in which the first base polymer is pulverized and then the raw materials are mixed with reinforcing agents, softeners, high-functional olefin resins, vulcanization activators, processing aids, and anti-foaming agents.

CMB rubber produced through this process is a material that does not undergo vulcanization even when heat is applied, so it cannot be molded into a product and can be stored for a long period of time. Optionally, CMB rubber can go through a process called maturation for a certain period of time or longer, which is intended to stabilize the high mechanical stress that the base polymer received during the manufacturing process.

Next, the FMB process is a process of mixing CMB rubber with a quantitative vulcanizing agent (sulfur) and a vulcanizing accelerator. These raw materials must be mixed to create a completed rubber composition.

The properties of the rubber compositions for Examples 1 and 2 and Comparative Examples 1 and 2 in Experimental Example 1 are as shown in Tables 3 and 4 below.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Basic properties of unvulcanized rubber Scotch
(Scorch at 125℃) Vm 25.5 21.5 21.2 23.6 T5 9'41 11'16 10'09 10'23 rheometer
(180℃×6 minutes) Tmax 40.5 37.4 36.9 38.5 Tmin 4.9 4.5 4.4 4.7 ts1 0'46 0'48 0'46 0'47 ts5 0'59 1'04 1'00 1'03 T10 0'56 0'58 0'56 0'59 T90 3'03 3'33 3'38 3'28

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 vulcanized rubber
Basic properties Basic properties hardness KS M 6518 72 70 69 71 tensile strength 149.3 127.3 124.2 131.8 Elongation rate 265.5 287.6 302.3 299.3 Aging properties
(70℃×72Hrs) Hardness change +1 +1 +1 +1 Tensile strength change 0 +2 0 +1 Change in elongation rate -2 -5 -4 -3 Compression strain rate (%)
(70℃×22Hrs) C/Set JIS K 6301 10.5 13.7 12.1 12.3 NBS wear performance Wear index KS M 6625 128 109 115 127

The rubber composition according to the present embodiment was designed with a focus on a hardness (Shore) of 70A, which is a general required property of a glass run corner molded part.

Referring to Tables 3 and 4, it can be confirmed that the rubber composition according to Example 1 has superior tensile strength and wear resistance compared to the rubber compositions manufactured according to Comparative Example 1 in which a high-functionality olefin resin was not used and Comparative Example 2 in which an LDPE resin was used.

Table 5 and Fig. 2 show the results of surface roughness measurements and surface photographs of specimens manufactured using the rubber compositions manufactured according to Example 1 and Comparative Examples 1 to 3. That is, the surface embossing effect was comparatively evaluated through surface roughness measurements for the rubber compositions according to Example 1 and Comparative Examples 1 to 2.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Surface roughness 1.109 Ra 0.045 Ra 0.037 Ra 0.529 R

Fig. 3 shows the equipment used to measure surface roughness in this embodiment. Specifically, the tip of the roughness meter needle, indicated by the yellow circle in Fig. 3, moves to measure surface roughness.

Referring to Table 5 and Fig. 2, in the case of Example 1, the surface embossing effect could be visually confirmed. In the case of Comparative Example 2 using LDPE resin, a POE product, it could be confirmed that the surface roughness was lower than in the case of Comparative Example 1 where POE was not added. It is thought that sufficient melting occurred during the specimen molding process, and due to this plasticization, the surface smoothness was relatively good and the surface roughness was low.

In addition, in the case of Comparative Example 3 using a UHMWPE product with a molecular weight similar to that of UHMWPP, it is judged that since it has a relatively low molecular weight and melting point compared to UHMWPP, a slight melting phenomenon occurred at a high molding temperature and surface roughness was not formed.

Normally, when the surface roughness of the corner molding part of a glass run product is 1.0 Ra or higher, the discoloration from the extruded cross-section can be minimized.

Experimental example 2

Rubber compositions were prepared according to Examples 2 to 3 and Reference Examples 1 to 2 by mixing at the composition ratios described in Table 6 below and varying the content of high-functionality olefin resin (UHMWPP).

Specifically, in Experimental Example 2, the rubber mixing was performed in the same manner as in Experimental Example 1. That is, the CMB rubber was mixed in a Banbury Mixer, and the FMB rubber was mixed in a Kneader.

The raw materials used were also the same as those in Experimental Example 1; the EPDM polymer was KEP-330 (Kumho Polychem), and the carbon black was HS-45 from Orion Engineering Carbons.

Additionally, ZnO (zinc oxide), Stearic Acid, and PEG#4000 (Poly Ethylene Glycol MW 4000) were used as vulcanization activators and processing aids.

The softener used was a paraffin-based rubber compounding oil.

division Reference Example 1 Example 2 Example 3 Reference example 2 CMB Polymer EPDM 100 100 100 100 Reinforcement Carbon Black 85 85 80 80 Softener Process Oil 40 40 40 40 High functionality
Olefin
profit UHMWPP 5 10 20 25 vulcanization activator
&
Processing preparation Zinc Oxide 8 8 8 8 Stearic Acid 1.5 1.5 1.5 1.5 PEG#4000 2 2 2 2 Process Aid 2 2 2 2 Anti-foaming agent Calcium Oxide 5 5 5 5 CMB Subtotal 248.5 253.5 258.5 263.5 FMB Emperor Sulfur 1.5 1.5 1.5 1.5 Vulcanization accelerator Accelerator MBT 0.7 0.7 0.7 0.7 Accelerator MBTS 0.3 0.3 0.3 0.3 Accelerator ZnBDC 1 1 1 1 Accelerator TMTD 0.5 0.5 0.5 0.5 Accelerator CBS 1.2 1.2 1.2 1.2 Total (CMB + FMB) 253.7 258.7 263.7 268.7

In Experimental Example 2, the properties of the rubber compositions for Examples 2 to 3 and Reference Examples 1 to 2 are as shown in Tables 7 and 8 below.

division Reference Example 1 Example 2 Example 3 Unvulcanized rubber
Basic properties Scotch
(Scorch at 125℃) Vm 24.3 25.5 26.8 T5 10’03 9'41 9’12 rheometer
(180℃×6 minutes) Tmax 39.2 40.5 41.8 Tmin 4.7 4.9 4.8 ts1 0’47 0'46 0’45 ts5 1’03 0'59 0’57 T10 0’57 0'56 0’55 T90 3’28 3'03 2’57

division Reference Example 1 Example 2 Example 3 vulcanized rubber
Basic properties Basic properties hardness KS M 6518 71 72 73 tensile strength 131.3 149.3 135.6 Elongation rate 273.2 265.5 255.1 Aging properties
(70℃×72Hrs) Hardness change +1 +1 +1 Tensile strength change +1 0 +1 Change in elongation rate -3 -2 -2 Compression strain rate (%)
(70℃×22Hrs) C/Set JIS K 6301 13.3 10.5 13.1

In Table 8, the physical properties of the rubber composition for Reference Example 2 could not be measured due to UHMWPP dispersibility issues.

Specifically, in Reference Example 2, in which 25 parts by weight of high-functionality olefin resin was added based on 100 parts by weight of polymer, the CMB rubber was found to be very dry.

Figures 4a and 4b show the poor dispersion state of the rubber composition of Reference Example 2. UHMWPP particles were visually confirmed on the surface (Figure 4a). In severe cases, white UHMWPP particles were separated and fell off (Figure 4b). This is thought to be a phenomenon that occurs because the excessively added UHMWPP was not sufficiently dispersed in the rubber compound.

Table 9 and Fig. 5 show the results of surface roughness measurements and surface photographs of specimens manufactured using rubber compositions manufactured according to Reference Example 1, Example 2, and Example 3.

division Reference Example 1 Example 2 Example 3 Surface roughness 0.125 Ra 1.109 Ra 1.313 Ra

Referring to Table 9 and Fig. 5, Reference Example 1, in which 5 parts by weight of UHMWPP was added based on 100 parts by weight of polymer, exhibited a surface embossing effect, but the embossing effect was significantly low. This is because the UHMWPP forming the surface roughness was insufficient.

In contrast, Examples 2 and 3, in which 10 parts by weight and 20 parts by weight of UHMWPP were added based on 100 parts by weight of polymer, respectively, had surface roughness measured in the range of 1.1 Ra to 1.4 Ra. In addition, referring to Fig. 5, it can be confirmed that the specimen surfaces of Examples 2 and 3 exhibited a greater embossing effect than Reference Example 1.

As a result, it can be confirmed that in order to implement an embossing effect for reducing the discoloration of a glass run joint molded part, it is appropriate to include the high-functionality olefin resin in an amount of 10 to 20 parts by weight based on 100 parts by weight of EPDM.

FIG. 6a shows a sample to which a glass run corner joint rubber manufactured using a rubber composition manufactured according to Comparative Example 1 of Experimental Example 1 has been applied, and FIG. 6b shows a sample to which a glass run corner joint rubber manufactured using a rubber composition manufactured according to Example 2 has been applied.

Referring to FIGS. 6a and 6b, it can be confirmed that a glass run product having excellent surface quality without a foreign color sensation can be implemented when using a rubber composition manufactured according to Example 2.

The present invention is not limited to the above embodiments, but can be manufactured in various different forms, and a person having ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims (15)

Containing ethylene propylene diene monomer (EPDM), reinforcing agent, softener, high-functionality olefin resin, vulcanization activator, processing aid, foam inhibitor, vulcanization agent, and vulcanization accelerator,
The above high-functionality olefin resin comprises ultra high molecular weight polypropylene (UHMWPP) having a weight average molecular weight (Mw) of 500,000 to 2,500,000 as measured by gel permeation chromatography (GPC).
EPDM rubber composition having a surface embossing effect on a glass run corner molding. In the first paragraph,
The above-mentioned high-functionality olefin resin is an EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP having a melting point of 110°C to 200°C as measured by differential scanning calorimetry (DSC). In the first paragraph,
The above-mentioned high-functionality olefin resin is an EPDM rubber composition having an embossing effect on the surface of a glass run corner molded part using UHMWPP having a melt index (MI) of 0.05 to 20 g/10 min as measured by ASTM D1238. delete In the first paragraph,
The content of the above high-functionality olefin resin is:
An EPDM rubber composition having a surface embossing effect of a glass run corner molded part using 6 to 24 parts by weight of UHMWPP based on the weight of the above ethylene propylene diene monomer (EPDM). In the first paragraph,
The above ethylene propylene diene monomer (EPDM) is an EPDM rubber composition having an embossing effect on the surface of a glass run corner molded part using UHMWPP having a patterned viscosity (ML1+4, 125°C) of 60 mu or less. In the first paragraph,
The above ethylene propylene diene monomer (EPDM) is an EPDM rubber composition having an embossing effect on the surface of a glass run corner molded part using UHMWPP having an ethylene norbornene (ENB) content of 7 wt% or more and an ethylene content of 60.0 wt% or less. In the first paragraph,
Based on 100 parts by weight of the above ethylene propylene diene monomer (EPDM),
75 to 100 parts by weight of the above reinforcing agent,
35 to 45 parts by weight of the above softener,
5 to 10 parts by weight of the above vulcanization activator,
2 to 5 parts by weight of the above processing agent,
3 to 5 parts by weight of the above anti-foaming agent,
1 to 2 parts by weight of the above vulcanizing agent, and
An EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP containing 2 to 5 parts by weight of the above-mentioned vulcanization accelerator. In the first paragraph,
An EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP, wherein the reinforcing agent comprises at least one of carbon black and silica. In the first paragraph,
The above reinforcing agent is an EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP having an average particle diameter in the range of 40 to 48 nm. In the first paragraph,
An EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP containing zinc oxide and stearic acid as the vulcanization activator. In the first paragraph,
The above processing aid is an EPDM rubber composition having an embossing effect on the surface of a glass run corner molded part using UHMWPP containing polyethylene glycol (PEG#4000: molecular weight 4,000) and a metal salt. In the first paragraph,
An EPDM rubber composition having a surface embossing effect of a glass run corner molded part using UHMWPP, wherein the vulcanization accelerator comprises at least one of MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), ZnBDC (zinc di-n-butyl dithiocarbamate), TMTD (tetramethylthiuram disulfide), and CBS (N-cyclohexyl-2-benzothiazyl sulfonamide). An automotive glass run product manufactured using an EPDM rubber composition having a surface embossing effect of a glass run corner molding part using UHMWPP according to any one of claims 1 to 3 and claims 5 to 13. In Article 14,
An automotive glass run product having a surface roughness of the corner forming part of the above glass run product of 1.0 Ra or higher.