KR20230057536A - Vulcanizing agent-free EPDM rubber Composition for weather strip, Glassrun Weather-strip For Vehicle using the same and manufacturing method of the Glassrun Weather-strip For Vehicle - Google Patents

Abstract

(상기 화학식 1에서, 각 치환기는 명세서에 정의된 바와 같다.)Includes EPDM (ethylene propylene diene monomer) rubber and two or more vulcanization accelerators, wherein the two or more vulcanization accelerators include a compound represented by Formula 1 below, and the two or more vulcanization accelerators are based on 100 parts by weight of the EPDM rubber A vulcanizing agent-free EPDM rubber composition for a weather strip containing 4 parts by weight or more, a glass run weather strip for automobiles manufactured using the same, and a manufacturing method of the glass run weather strip for automobiles are provided.
[Formula 1]

(In Formula 1, each substituent is as defined in the specification.)

Description

Vulcanizing agent-free EPDM rubber composition for weather strip, Glassrun weather strip for automobiles using the same and manufacturing method thereof Weather-strip For Vehicle}

The present disclosure relates to an EPDM rubber composition for a vulcanizing agent-free weather strip, a glass run weather strip for automobiles manufactured using the same, and a method for manufacturing the glass run weather strip for automobiles.

A weather strip is an automobile part used to prevent noise, dust, rainwater, etc. from entering the inside of a vehicle by being mounted on a vehicle door and the rim of a vehicle body to seal the inside and outside of the vehicle. In addition, it is possible to secure comfort and comfort in the interior of the vehicle by buffering shocks that may occur during the process of opening and closing the vehicle door.

These weather strips generally use ethylene-propylene-diene monomer, which has excellent weather resistance and ozone resistance, as a base polymer.

The weather strip is attached to the interface between the car door and the body to perform a sealing function. However, if the elastic restoring force is lowered due to long-term use, that is, if the sealing performance is lowered, noise, dust, rainwater, etc. It becomes difficult to perform the function. Therefore, in order to preserve the sealing power of a vehicle for a long time and secure functional characteristics, the compression set is the most important among the physical properties of rubber.

One embodiment relates to an EPDM rubber compound capable of manufacturing parts such as a weather strip, that is, a door, a body weather strip, which is a sealing component for automobiles, and more specifically is to provide a vulcanizing agent-free EPDM rubber composition that does not use a vulcanizing agent (sulfur) used to impart elasticity to rubber.

Another embodiment is to provide a glass run weather strip for automobiles manufactured using the EPDM rubber composition for a vulcanizing agent-free weather strip.

Another embodiment is to provide a manufacturing method of the glass run weather strip for automobiles.

One embodiment includes EPDM (ethylene propylene diene monomer) rubber and two or more types of vulcanization accelerators, wherein the two or more types of vulcanization accelerators include a compound represented by Formula 1 below, and the two or more types of vulcanization accelerators are the EPDM rubber A vulcanizing agent-free EPDM rubber composition for a weather strip containing 4 parts by weight or more relative to 100 parts by weight is provided.

[Formula 1]

In Formula 1,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

R ¹ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,

L ¹ and L ² are each independently a substituted or unsubstituted C1 to C20 alkylene group;

n1 is an integer from 0 to 4;

The two or more vulcanization accelerators may be included in an amount of 5 parts by weight or more based on 100 parts by weight of the EPDM rubber.

The two or more vulcanization accelerators may further include a compound represented by Formula 2 below.

[Formula 2]

In Formula 2,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

L ¹ to L ⁴ are each independently a substituted or unsubstituted C1 to C20 alkylene group.

The compound represented by Formula 2 may be included in a higher amount than the compound represented by Formula 1.

The two or more vulcanization accelerators may further include a compound represented by Formula 3 below.

[Formula 3]

In Formula 3,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

R ² to R ⁵ are each independently a substituted or unsubstituted C1 to C20 alkyl group.

The compound represented by Formula 3 may be included in a smaller amount than the compound represented by Formula 1.

The two or more vulcanization accelerators may further include a compound represented by Formula 4 below.

[Formula 4]

In Formula 4,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

L ¹ to L ⁴ are each independently a substituted or unsubstituted C1 to C20 alkylene group.

The compound represented by Formula 4 may be included in a larger amount than the compound represented by Formula 1, and may be included in a smaller amount than the compound represented by Formula 2.

The two or more vulcanization accelerators may further include zinc dibutyl dithiocarbamate.

The zinc dibutyl dithiocarbamate may be included in a smaller amount than the compound represented by Chemical Formula 3.

The two or more vulcanization accelerators may further include zinc diethyldithiocarbamate.

The zinc diethyldithiocarbamate may be included in a smaller amount than the compound represented by Chemical Formula 3.

The ethylene propylene diene monomer (EPDM) rubber may have a pattern viscosity of 70 to 100 (ML1+8, 125° C.), an ethylene content of 45% to 60%, and an ENB content of 8% or more.

The EPDM rubber composition for the vulcanizer-free weather strip may further include carbon black, process oil, and calcium carbonate, and may further include zinc oxide, stearic acid, a processing aid, and calcium oxide.

The EPDM rubber composition for the vulcanizing agent-free weather strip includes 65 parts by weight to 75 parts by weight of the carbon black, 55 parts by weight to 65 parts by weight of the process oil, based on 100 parts by weight of the EPDM (ethylene propylene diene monomer) rubber, 0.1 to 20 parts by weight of the calcium carbonate, 5 to 8 parts by weight of the zinc oxide, 1 to 2 parts by weight of the stearic acid, 1 to 3 parts by weight of the processing aid and 1 to 1 part by weight of the calcium oxide 7 parts by weight.

The EPDM rubber composition for the vulcanizing agent-free weather strip may further include a moisture absorbent and a foaming agent.

The EPDM rubber composition for the vulcanizing agent-free weather strip may include 3 to 5 parts by weight of the moisture absorbent and 1 to 3 parts by weight of the foaming agent based on 100 parts by weight of the ethylene propylene diene monomer (EPDM) rubber. there is.

The foaming agent may include a compound represented by Formula 5 below.

[Formula 5]

In Formula 5,

X' is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or NR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group).

Another embodiment provides a glass run weather strip for automobiles manufactured using the vulcanizing agent-free EPDM rubber composition.

Another embodiment is a) adding EPDM (ethylene propylene diene monomer) rubber, zinc oxide, stearic acid, a processing aid, calcium oxide, and conventional additives at the same time, followed by Soviet; b) adding carbon black, process oil and calcium carbonate; c) preparing a carbon master batch (CMB) composition by aging for 20 to 30 hours; and d) adding and kneading two or more vulcanization accelerators to the CMB composition to prepare a Final Master Batch (FMB) composition, wherein the two or more vulcanization accelerators include a compound represented by Formula 1 below, wherein Two or more vulcanization accelerators are included in an amount of at least 4 parts by weight based on 100 parts by weight of the EPDM rubber, thereby providing a method for manufacturing a glass run weather strip for automobiles.

[Formula 1]

(In Formula 1 above,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

R ¹ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,

L ¹ and L ² are each independently a substituted or unsubstituted C1 to C20 alkylene group;

n1 is an integer from 0 to 4)

The specific details of other aspects of the present invention are included in the detailed description below.

The EPDM rubber composition for a vulcanizing agent-free weather strip according to an embodiment has an excellent compression set in the mid- to long-term, so that the sealing function of the weather strip is maintained for a long time and a product with excellent sponge sensitivity can be obtained. In addition, discoloration and contamination can be reduced due to excellent heat resistance. Accordingly, a weather strip for automobiles manufactured using the EPDM rubber composition for a vulcanizing agent-free weather strip according to an embodiment may secure excellent product properties.

1 is a photograph of a cross-section of a weather strip extruded prepared from a composition according to Example 1.
2 is a photograph of an extruded cross-section of a weather strip made of a composition according to Comparative Example 1.
3 to 5 are photographs of devices for measuring the permanent compression set of a weather strip profile.

Unless otherwise specified herein, "substituted" to "substituted" means that one or more hydrogen atoms in the functional group of the present invention is a halogen atom (F, Br, Cl or I), a hydroxyl group, a nitro group, a cyano group, an amino group ( NH ₂ , NH(R ²⁰⁰ ) or N(R ²⁰¹ )(R ²⁰² ), wherein R ²⁰⁰ , R ²⁰¹ and R ²⁰² are the same or different from each other, and are each independently a C1 to C10 alkyl group), an amidino group, A hydrazine group, a hydrazone group, a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alicyclic organic group, a substituted or unsubstituted aryl group, And means substituted with one or more substituents selected from the group consisting of a substituted or unsubstituted heterocyclic group.

In this specification, unless otherwise specified, "alkyl group" means a C1 to C20 alkyl group, specifically means a C1 to C15 alkyl group, and "cycloalkyl group" means a C3 to C20 cycloalkyl group, specifically C3 to C18 cycloalkyl group, "alkoxy group" means a C1 to C20 alkoxy group, specifically means a C1 to C18 alkoxy group, "aryl group" means a C6 to C20 aryl group, and specifically means a C6 to C20 alkoxy group. Means a C18 aryl group, "alkenyl group" means a C2 to C20 alkenyl group, specifically means a C2 to C18 alkenyl group, "alkylene group" means a C1 to C20 alkylene group, specifically C1 to C18 alkylene group, and "arylene group" means a C6 to C20 arylene group, specifically a C6 to C16 arylene group.

Unless otherwise defined herein, "combination" means mixing or copolymerization. Further, "copolymerization" means block copolymerization or random copolymerization, and "copolymer" means block copolymer or random copolymer.

Unless otherwise defined in the chemical formula within this specification, if a chemical bond is not drawn at a position where a chemical bond is to be drawn, it means that a hydrogen atom is bonded to the position.

Unless otherwise defined in this specification, "*" means a moiety connected to the same or different atom or chemical formula.

The present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and the spirit of the present invention will be sufficiently conveyed to those skilled in the art.

The present invention relates to a sponge rubber composition used for a weather strip, which is a sealing component for automobiles, that is, an EPDM rubber composition, and specifically, includes EPDM (ethylene propylene diene monomer) rubber and two or more vulcanization accelerators, and The vulcanization accelerator includes a compound represented by Formula 1 below, and the two or more vulcanization accelerators are included in an amount of 4 parts by weight or more based on 100 parts by weight of the EPDM rubber.

[Formula 1]

In Formula 1,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

R ¹ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,

L ¹ and L ² are each independently a substituted or unsubstituted C1 to C20 alkylene group;

n1 is an integer from 0 to 4;

The EPDM rubber composition for weather strip according to an embodiment does not use sulfur (rubber vulcanizing agent), which is commonly used, and has a vulcanization system centered on a sulfur donor, through which sulfur (rubber vulcanizing agent) is used. Vulcanizing agent) can have a more excellent compression set compared to the conventional EPDM rubber composition.

Rubber crosslinking methods include sulfur crosslinking, peroxide crosslinking, and resin crosslinking, but the present invention relates to a sulfur crosslinking method.

Sulfur crosslinking is formed when sulfur is combined in the double bond structure of a base polymer such as EPDM rubber, and the sulfur component is essential to impart elasticity to rubber formulations.

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

When sulfur in a cyclic structure is decomposed and converted into a sulfur structure in a chain structure, it has various structures (-S-, -S-S-, -Sx- x≥3), and these sulfur forms participate in crosslinking. It has a mono-sulfide bond, a disulfide bond, and a poly-sulfide bond in the form of a mono-sulfide bond, and usually each bond energy is shown in Table 1 below.

(Unit: KJ/mol) structure rubber vulcanization binding energy Polysulfide *-C-Sx-C-* (x ≥ 3) < 270 Disulfide *-CS ₂ -C-* 270 Monosulfide *-C-S-C-* 285 Carbon-Carbon *-C-C-* 350

The *-carbon-carbon-* bond with the highest binding energy has the best rubber properties according to heat aging, but since this is a structure that cannot appear in the sulfur bridge system, the monosulfide bond structure (*-C-S-C-*) is sulfur bridged. The best heat resistance can be secured in However, it is a reality that there is a limit to securing high heat resistance properties because the chain-like sulfur structure formed is random when sulfur in the rubber-like structure is decomposed.

Therefore, the present inventors have repeatedly studied and studied in order to develop a rubber crosslinking system that can have as many monosulfide bonding structures as possible, and completed the present invention after two years of research and development.

Specifically, instead of not using a sulfur vulcanizing agent at all, two or more vulcanization accelerators were used. part or more), it is possible to provide an EPDM rubber composition having a much better compression set than the prior art using a sulfur vulcanizing agent.

Hereinafter, each component constituting the vulcanizing agent-free EPDM rubber composition for a weather strip will be described one by one.

<EPDM Rubber>

A weather strip is a sealing component for automobiles and requires high weather ability. Therefore, in order to secure high weather resistance, EPDM rubber with excellent weather resistance is used worldwide.

In addition, since it is manufactured by a high-temperature continuous extrusion vulcanization method, the shape retention and stability of the extrusion profile are the most important factors.

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

The weatherstrip products manufactured by the continuous extrusion vulcanization method use solid rubber and an EPDM compound called sponge rubber, and for sponge rubber, EPDM rubber with a high pattern viscosity is generally used to secure the shape stability of the extruded section.

However, EPDM rubber with high pattern viscosity may be limited in viscosity because processability is disadvantageous in the compound manufacturing process. Therefore, it may be preferable to use an EPDM rubber having a texture viscosity of 70 to 100 (ML1+8, 125°C).

In addition, ENB (Ethylidene norbornene), which has a double bond structure as the third component of EPDM, is advantageous in obtaining a product with a high content in securing rubber crosslinking, sponge shape stability, and high crosslinking properties, for example, with an ENB content of 8% or more Products, such as products with an ENB content of 8% to 9%, can be used for making sponge rubber.

The area where the sponge rubber of the weather strip is formed basically not only serves as a sealing function, but also may affect the opening/closing performance. As an EPDM rubber property that can affect opening and closing performance, the ethylene/propylene content ratio can act as an important factor. In general, when the ethylene content with high crystallinity is high, sponge rubber can be hard not suitable for Therefore, products with a relatively low ethylene content are preferred. For example, EPDM rubber having an ethylene content of 45% to 60% may be advantageous in securing not only high sealing performance but also opening and closing performance.

<Vulcanization accelerator>

In general, in preparing a sponge rubber composition for a weather strip, sulfur (Free Sulfur), which is an essential element of rubber vulcanization, is added and used.

When sulfur is added to rubber and heat is applied, individual polymer chains are formed into a three-dimensional network by a chemical reaction with sulfur, which is called vulcanization. At this time, the use of a vulcanization accelerator increases the vulcanization rate and enables efficient vulcanization at a relatively low temperature, which is the most commonly used manufacturing principle of rubber products throughout the rubber industry.

However, sulfur added as an essential component of rubber vulcanization has a cyclic S8 structure, and various chain structures (-S-, -S-S-, -Sx- x≥3) are formed during the decomposition process. When the structure of each chain sulfur participates in the vulcanization reaction, structures with various binding energies are formed (see Table 1).

In general, as the number of monosulfide bonds with a small number of sulfur increases, compression set and heat aging characteristics may be excellent, which is known to be obtained through vulcanization at a low temperature for a long time. However, this has the disadvantage of increasing manufacturing cost and lowering productivity.

Therefore, the inventors of the present invention, in order to improve these problems and to manufacture a weather strip using sponge rubber having excellent compression set and heat aging characteristics, obtained excellent compression set and heat by using a sulfur-donating vulcanization accelerator without using sulfur. Aging properties were secured.

Conventionally, when classifying rubber vulcanization systems, the ratio of the amount of sulfur used and the amount of vulcanization accelerator used is used. At this time, sulfur is recommended to be used within the range of 0.4 parts by weight to 3.5 parts by weight based on 100 parts by weight of rubber. This is judged to be the amount used considering the productivity and quality characteristics of the product, but the present invention was developed to use only a sulfur-donating vulcanization accelerator that is not classified as such a conventional rubber vulcanization system, that is, without using sulfur at all, which has high heat resistance It was confirmed that there is higher heat resistance compared to EV (Efficient Vulcanization) rubber vulcanization system applied to the required rubber formulation.

Since the present invention does not use sulfur, mono-sulfide bond crosslinking is excellent, and accordingly, heat resistance is excellent. Since sulfur is not used, that is, because a sulfur-donating vulcanization accelerator is used instead of sulfur, the type and amount of the sulfur-donating vulcanization accelerator is very important, and if any of these conditions are not satisfied, an excellent compression set is achieved. It becomes difficult to do.

For example, the two or more vulcanization accelerators may be included in an amount of 5 parts by weight or more based on 100 parts by weight of the EPDM rubber. When the two or more vulcanization accelerators are included in an amount of less than 4 parts by weight, for example, less than 5 parts by weight, based on 100 parts by weight of the EPDM rubber, the effect of improving the compression set may be reduced, which may be undesirable.

The compound represented by Formula 1 has excellent scorch stability and contains 11% of active sulfur.

For example, in Formula 1, X is a nitrogen atom, L ¹ and L ² are each independently a substituted or unsubstituted C1 to C10 alkylene group, and n1 may be an integer of 0.

For example, in Formula 1, L ¹ to L ⁴ may each independently represent a substituted or unsubstituted methylene group or a substituted or unsubstituted ethylene group.

For example, the two or more vulcanization accelerators may further include a compound represented by Formula 2 below.

[Formula 2]

In Formula 2,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

L ¹ to L ⁴ are each independently a substituted or unsubstituted C1 to C20 alkylene group.

For example, in Chemical Formula 2, X is a nitrogen atom, and L ¹ to L ⁴ may each independently be a substituted or unsubstituted C1 to C10 alkylene group.

For example, in Formula 2, L ¹ to L ⁴ may each independently represent a substituted or unsubstituted methylene group or a substituted or unsubstituted ethylene group.

The compound represented by Formula 2 is decomposed at a high vulcanization temperature, and at this time, 27% of active sulfur is released. The released active sulfur participates in rubber vulcanization. That is, when the compound represented by Chemical Formula 2 is used together with the compound represented by Chemical Formula 1, the amount of sulfur used can be greatly reduced.

For example, the compound represented by Formula 2 may be included in a greater amount than the compound represented by Formula 1.

For example, the two or more vulcanization accelerators may further include a compound represented by Formula 3 below.

[Formula 3]

In Formula 3,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

R ² to R ⁵ are each independently a substituted or unsubstituted C1 to C20 alkyl group.

For example, in Formula 3, X is a nitrogen atom, and R ¹ to R ⁴ may each independently be a substituted or unsubstituted C1 to C10 alkyl group.

For example, in Formula 3, R ¹ to R ⁴ may each independently be a substituted or unsubstituted methyl group or a substituted or unsubstituted ethyl group.

The compound represented by Formula 3 has excellent vulcanization accelerator and releases 13% of active sulfur during decomposition. Compared to other vulcanization accelerators, it has excellent accelerating power despite having a low price.

For example, the compound represented by Formula 3 may be included in a smaller amount than the compound represented by Formula 1.

For example, the two or more vulcanization accelerators may further include a compound represented by Formula 4 below.

[Formula 4]

In Formula 4,

X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,

L ¹ to L ⁴ are each independently a substituted or unsubstituted C1 to C20 alkylene group.

For example, in Chemical Formula 4, X is a nitrogen atom, and L ¹ to L ⁴ may each independently be a substituted or unsubstituted C1 to C10 alkylene group.

For example, in Formula 4, L ¹ to L ⁴ may each independently represent a substituted or unsubstituted methylene group or a substituted or unsubstituted ethylene group.

The compound represented by Formula 4 is a super accelerator with strong vulcanization accelerator, has excellent vulcanization properties and is free from contamination, and contains 25% of active sulfur.

For example, the compound represented by Formula 4 may be included in a larger amount than the compound represented by Formula 1, and may be included in a smaller amount than the compound represented by Formula 2.

For example, the two or more vulcanization accelerators may include all of the compounds represented by Chemical Formulas 1 to 4, and in this case, the relationship between the contents of the compounds represented by Chemical Formulas 1 to 4 may be as follows.

Compound represented by Formula 2 > Compound represented by Formula 4 > Compound represented by Formula 1 > Compound represented by Formula 3

For example, the two or more vulcanization accelerators may further include zinc dibutyl dithiocarbamate.

For example, the zinc dibutyl dithiocarbamate may be included in a smaller amount than the compound represented by Chemical Formula 3.

For example, the two or more vulcanization accelerators may further include zinc diethyldithiocarbamate.

For example, the zinc diethyldithiocarbamate may be included in a smaller amount than the compound represented by Chemical Formula 3.

When the vulcanization accelerator in the vulcanizing agent-free EPDM rubber composition according to one embodiment satisfies the above conditions, the composition according to one embodiment can provide a weather strip having a very excellent compression set.

For example, the vulcanizer-free EPDM rubber composition may further include carbon black, process oil, and calcium carbonate.

<Rubber Reinforcement and Softener>

Carbon black, which is commonly used as a reinforcing agent for rubber, is classified into N100 ~ N900 according to the ASTM standard according to the particle size. However, N200 ~ N300 products with small particle size are generally used for tire products requiring high durability, and N700 ~ N900 products are generally used for products requiring high dynamic characteristics, but N500 products are generally used for weather strips.

For example, the carbon black may be N550, that is, a Fast Extrusion Furnace (FEF) product. In this case, a smooth plane can be obtained for the extruded product, the reinforcing property is excellent, and the heat generation can be relatively small.

Typically, it may be included in the range of 65 parts by weight to 75 parts by weight based on 100 parts by weight of the base polymer EPDM rubber. When the carbon black is included in less than 65 parts by weight based on 100 parts by weight of EPDM rubber, mechanical properties may be significantly deteriorated, and when it is included in more than 75 parts by weight, high hardness and flowability in the extrusion process are lowered. Extrusion is difficult.

Weatherstrip products are functional parts but require high emotional quality. Therefore, since the rubber softener used in the present invention may cause emotional quality issues such as discoloration and discoloration, paraffin oil (process oil) that is relatively excellent in discoloration, discoloration, and heat aging can be used.

The process oil may be included in the range of 55 parts by weight to 65 parts by weight based on 100 parts by weight of EPDM rubber. When the process oil is included in an amount of less than 55 parts by weight based on 100 parts by weight of EPDM rubber, dispersibility and processability are deteriorated, and a problem occurs in the opening and closing performance of a car because the hardness is increased, and when it exceeds 65 parts by weight, dispersibility is deteriorated , which can lead to deterioration of sealing performance.

In addition, in order to improve the appearance quality and cost competitiveness of the sponge extrusion profile, the composition according to one embodiment may further include calcium carbonate, wherein the calcium carbonate is 0.1 to 20 parts by weight based on 100 parts by weight of EPDM rubber. may be included in the range. If the calcium carbonate is included in an amount exceeding 20 parts by weight based on 100 parts by weight of the EPDM rubber, poor dispersion and deterioration in physical properties may occur.

<Other usual additives>

For example, the vulcanizer-free EPDM rubber composition for weather strip may further include zinc oxide, stearic acid, a processing aid, and calcium oxide.

Zinc oxide and fatty acids can be used as the vulcanization activator, which can improve the vulcanization accelerator by forming a metal salt.

For example, the zinc oxide may be included in 5 parts by weight to 8 parts by weight based on 100 parts by weight of EPDM rubber, and the fatty acid may be included in 1 part by weight to 2 parts by weight based on 100 parts by weight of EPDM rubber. When the zinc oxide is included in an amount of less than 5 parts by weight based on 100 parts by weight of the EPDM rubber, vulcanization activity may be reduced, and if it exceeds 8 parts by weight, poor dispersion may occur.

For example, the fatty acid may include stearic acid, and when included in less than 1 part by weight based on 100 parts by weight of EPDM rubber, a decrease in vulcanization activity may occur, and if it exceeds 2 parts by weight, unreacted Fatty acid is transferred to the surface and blooming, which is called whitening, may occur, which may be a factor that causes deterioration in weather strip sensitivity.

<Blowing agent and moisture absorbent>

For example, the EPDM rubber composition for the vulcanizing agent-free weather strip may further include a moisture absorbent and a foaming agent.

In the high-temperature continuous extrusion vulcanization process, which is a weather strip manufacturing process, the use of a moisture absorbent can be very important. This means that if the raw material used in the sponge rubber manufacturing process contains a small amount of moisture, when it passes through the high-temperature vulcanization process, it may vaporize and form porosity inside, which is similar to a foaming agent for rubber. However, since the foaming agent for rubber can be controlled in operating the rubber composition, the formation of pores due to moisture inside the raw material cannot be controlled, so it may be preferable to use 3 to 5 parts by weight compared to 100 parts by weight of EPDM rubber. . When the moisture absorbent is used in an amount less than 3 parts by weight relative to 100 parts by weight of EPDM rubber, it is impossible to completely remove internal moisture, which may cause deterioration in the emotional quality of the product surface, and when used in excess of 5 parts by weight, poor dispersion and deterioration in physical properties may occur.

For example, based on 100 parts by weight of the ethylene propylene diene monomer (EPDM) rubber, the foaming agent may be included in an amount of 1 part by weight to 3 parts by weight.

For example, the foaming agent may include a compound represented by Formula 5 below, but is not necessarily limited thereto.

[Formula 5]

In Formula 5,

X' is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or NR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group).

Another embodiment provides a glass run weather strip for automobiles manufactured using the EPDM rubber composition for a vulcanizing agent-free weather strip.

Another embodiment is a) adding EPDM (ethylene propylene diene monomer) rubber, zinc oxide, stearic acid, a processing aid, calcium oxide, and conventional additives at the same time, followed by Soviet; b) adding carbon black, process oil and calcium carbonate; c) preparing a carbon master batch (CMB) composition by aging for 20 to 30 hours; and d) preparing a FMB (Final Master Batch) composition by adding and kneading two or more vulcanization accelerators to the CMB composition, wherein the two or more vulcanization accelerators include the compound represented by Formula 1, Two or more vulcanization accelerators are included in an amount of at least 4 parts by weight based on 100 parts by weight of the EPDM rubber, thereby providing a method for manufacturing a glass run weather strip for automobiles.

Specifically, the manufacturing method of the present invention can be manufactured by dividing into CMB (Carbon Master Batch) and FMB (Final Master Batch). CMB rubber (composition) was mixed by adding carbon black, process oil, calcium carbonate, zinc oxide and stearic acid as vulcanization activators, and PEG#4000 as vulcanization activator, centering on EPDM rubber as the base polymer. Equipment can use closed mixers such as Banbury Mixer, Inter-Mixer, and Kneadeer. This is more advantageous than an open mixer (eg, Open Mill - a mixing facility using two cylindrical rolls) in ensuring rapid productivity and dispersion during the mixing process or leakage to the outside during the mixing process.

After the preparation of the CMB rubber (composition) is completed, the FMB rubber (composition) must be manufactured after about 24 hours of aging time.

CMB and FMB processes can use conventional rubber mixing methods.

Hereinafter, preferred embodiments of the present invention will be described. However, the following examples are only preferred examples of the present invention, and the present invention is not limited by the following examples.

(Example)

Preparation of EPDM rubber composition for weather strip

An EPDM rubber composition for a weather strip was prepared according to the composition shown in Table 2 below.

Specifically, CMB was prepared in a Banbari mixer, and after aging for 24 hours or more, FMB was prepared in a Banbari mixer. In the CMB manufacturing process, EPDM rubber (KEP-2480: Kumho Polychem), zinc oxide, stearic acid, WB-16 (Rubber Processing Aid from Struktol, Germany), PEG#4000, and calcium oxide are simultaneously added to perform mastification. It was prepared by adding carbon black (HS45 carbon black from Orion Engineered Carbons), process oil, and calcium carbonate. And, after passing through the rubber aging time of 24 hours or more, it was prepared by adding a vulcanizing agent and/or a vulcanization accelerator according to the composition ratio of each raw material.

The EPDM rubber used in the present invention was a product of Kumho Polychem, which is the most widely known product for sponge-type rubber, and its basic physical properties are shown in Table 3 below.

division comparative example Example One 2 3 4 One CMB KEP-2480 100 100 100 100 100 Carbon Black N550 73 73 78 78 78 process oil 63 63 58 58 58 Calcium Carbonate (CaCO ₃ ) 20 20 20 20 20 Zinc Oxide (ZnO) 5 5 5 5 5 stearic acid One One One One One WB-16 2 2 2 2 2 PEG#4000 - - 1.5 1.5 2.5 Calcium Oxide (CaO) 4 4 4 4 4 CMB subtotal 268 268 269.5 269.5 270.5 FMB S (Sulfur: Vulcanizing agent) 1.2 - - - - Vulcanization accelerator
(2-mercaptobenzothiazole) 1.5 1.5 1.5 - - Vulcanization accelerator [2-(4'-Morpholinodithio) benzothiazole] - - - 1.5 One Vulcanization accelerator (Zinc Dibutyldithiocarbamate) 0.7 0.7 0.5 - 0.3 Vulcanization accelerator (Zinc Diethyldithiocarbamate) 0.5 0.5 0.5 - 0.3 Vulcanization accelerator (Ethylene Thiourea) 0.5 0.5 - - - Vulcanization accelerator (4-4'-Dithiodimorpholine) - - 1.5 1.5 1.5 Vulcanization accelerator (Tetramethylthiuram disulfide) - - 0.7 0.7 0.7 Vulcanization accelerator (Dipentamethylenethiuram tetrasulfide) 0.3 0.3 0.3 - 1.2 Total (CMB + FMB) 272.7 271.5 274.5 273.2 275.5

division result Pattern viscosity (ML1+8, 125℃) 81 ethylene content 58% ENB content 8.9% molecular weight distribution Bimodal

(evaluation)

Basic physical properties of the vulcanized rubber prepared by vulcanizing the EPDM rubber composition for weather strip according to Example 1 and Comparative Examples 1 to 4 were measured, and the results are shown in Table 4 below.

division comparative example Example One 2 3 4 One Vulcanized rubber
basic physical properties general physical properties importance - 1.121 1.122 1.131 1.132 1.133 Hardness Shore A 57 51 55 56 58 tensile strength kg/cm ² 88 66 83 84 91 M (100%) kg/cm ² 25 23 23 23 24 elongation rate % 378 355 371 373 385 aging properties
(70℃×72 hours) change in hardness Shore A +1 +3 +1 +1 +1 Tensile strength change rate % +2.1 +3.9 +1.2 +1.2 +1.1 rate of change of elongation % -1.5 -5.2 -2.1 -2.1 -0.3 compression permanent harmonics short-term mode
(70℃×22 hours) 9.3 15.5 10.9 10.9 8.3 long term mode
(85℃×45 hours) 22.5 27.9 22.9 23.0 14.8

From Table 4, in the case of Comparative Example 2, even though sulfur was not used at all, it was confirmed that the physical properties were significantly deteriorated. When the sulfur donating accelerator was added in Comparative Example 3, a relatively high vulcanization reaction occurred compared to Comparative Example 2, but this could not secure a degree of crosslinking suitable for weather strip sponge rubber. Therefore, in order to have the effect of improving physical properties without using sulfur at all, as in Example 1, it can be confirmed that control of the type and amount of the sulfur-donating vulcanization accelerator is essential.

Manufacture of weather strip for sponge

According to the composition shown in Table 5 below, a foaming agent was added to the compositions of Example 1 and Comparative Example 1, and a continuous extrusion vulcanization method was applied at a high temperature to prepare a weather strip for sponge.

Comparative Example 1 Example 1 CMB KEP-2480 100 100 Carbon Black N550 73 78 process oil 63 58 Calcium Carbonate (CaCO ₃ ) 20 20 Zinc Oxide (ZnO) 5 5 stearic acid One One WB-16 2 2 PEG#4000 - 2.5 Calcium Oxide (CaO) 4 4 CMB subtotal 268 270.5 FMB S (Sulfur: Vulcanizing agent) 1.2 - Vulcanization accelerator
(2-mercaptobenzothiazole) 1.5 - Vulcanization accelerator [2-(4'-Morpholinodithio) benzothiazole] - One Vulcanization accelerator (Zinc Dibutyldithiocarbamate) 0.7 0.3 Vulcanization accelerator (Zinc Diethyldithiocarbamate) 0.5 0.3 Vulcanization accelerator (Ethylene Thiourea) 0.5 - Vulcanization accelerator (4-4'-Dithiodimorpholine) - 1.5 Vulcanization accelerator (Tetramethylthiuram disulfide) - 0.7 Vulcanization accelerator (Dipentamethylenethiuram tetrasulfide) 0.3 1.2 Blowing agent (4,4'-Oxybis (benzenesulfonyl hydrazide)) 2.25 2.1

(evaluation)

The foaming specific gravity, compression set, and whitening evaluation results of the weather strips for sponge according to Example 1 and Comparative Example 1 are shown in Table 6 below.

Comparative Example 1 Example 1 weather strip
(sponge foam) specific gravity of foam - 0.561 0.558 permanent compression set
(25% deflection) short-term mode
(70℃×22 hours) 16.9 13.1 long term mode
(85℃×45 hours) 25.8 21.8 bleaching evaluation 80℃×720℃ no whitening no whitening

The weatherstrip extrudate is manufactured by a continuous extrusion vulcanization method, which is commonly referred to as an extrusion vulcanization method. An extrudate is manufactured through an extrusion die, and vulcanization and foaming are performed simultaneously while passing through a high-temperature space called an oven. At this time, this extrudate was carried out at a set temperature inside the oven zone of 260 ℃.

From Table 6, it can be seen that the weather strip according to Example 1 has a higher permanent compression set than the weather strip according to Comparative Example 1.

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those skilled in the art to which the present invention pertains may take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented with Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

Claims (21)

Contains EPDM (ethylene propylene diene monomer) rubber and two or more vulcanization accelerators,
The two or more vulcanization accelerators include a compound represented by Formula 1 below,
The two or more vulcanization accelerators are contained in an amount of 4 parts by weight or more based on 100 parts by weight of the EPDM rubber. A sulfur-free EPDM rubber composition for weather strip:
[Formula 1]

In Formula 1,
X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,
R ¹ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,
L ¹ and L ² are each independently a substituted or unsubstituted C1 to C20 alkylene group;
n1 is an integer from 0 to 4;
In paragraph 1,
The two or more vulcanization accelerators are included in an amount of 5 parts by weight or more based on 100 parts by weight of the EPDM rubber.
In paragraph 1,
The two or more vulcanization accelerators further include a compound represented by Formula 2 below:
[Formula 2]

In Formula 2,
X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,
L ¹ to L ⁴ are each independently a substituted or unsubstituted C1 to C20 alkylene group.
In paragraph 3,
The compound represented by Formula 2 is included in a higher amount than the compound represented by Formula 1. A sulfur-free EPDM rubber composition for weather strips.
In paragraph 1,
The two or more vulcanization accelerators further include a compound represented by Formula 3 below:
[Formula 3]

In Formula 3,
X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,
R ² to R ⁵ are each independently a substituted or unsubstituted C1 to C20 alkyl group.
In paragraph 5,
The compound represented by Chemical Formula 3 is contained in a smaller amount than the compound represented by Chemical Formula 1. A sulfur-free EPDM rubber composition for a weather strip.
In paragraph 3,
The two or more vulcanization accelerators further include a compound represented by Formula 4 below:
[Formula 4]

In Formula 4,
X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,
L ¹ to L ⁴ are each independently a substituted or unsubstituted C1 to C20 alkylene group.
In paragraph 7,
The compound represented by Chemical Formula 4 is included in a higher amount than the compound represented by Chemical Formula 1, and the compound represented by Chemical Formula 2 is contained in a smaller amount than a vulcanizing agent-free (sulfur-free) EPDM for weather strip rubber composition.
In paragraph 5,
The two or more vulcanization accelerators further comprise zinc dibutyldithiocarbamate-free EPDM rubber composition for weather strips.
In paragraph 9,
The zinc dibutyl dithiocarbamate is contained in a smaller amount than the compound represented by Formula 3 above.
In paragraph 5,
The two or more vulcanization accelerators further comprise zinc diethyldithiocarbamate-sulfur-free EPDM rubber composition for weather strips.
In paragraph 9,
The zinc diethyldithiocarbamate is included in a lower content than the compound represented by Formula 3 above - a sulfur-free EPDM rubber composition for a weather strip.
In paragraph 1,
The EPDM (ethylene propylene diene monomer) rubber has a pattern viscosity of 70 to 100 (ML1 + 8, 125 ° C), an ethylene content of 45% to 60%, and an ENB content of 8% or more. free) EPDM rubber composition for weather strip.
In paragraph 1,
The vulcanizer-free (sulfur-free) EPDM rubber composition for the weather strip further comprises carbon black, process oil and calcium carbonate - the vulcanizer-free (sulfur-free) EPDM rubber composition for the weather strip.
In paragraph 14,
The vulcanizing agent-free (sulfur-free) EPDM rubber composition for a weather strip further comprises zinc oxide, stearic acid, a processing aid and calcium oxide.
In clause 15,
The vulcanizer-free (sulfur-free) EPDM rubber composition for weather strip,
65 to 75 parts by weight of the carbon black, 55 to 65 parts by weight of the process oil, 0.1 to 20 parts by weight of the calcium carbonate, based on 100 parts by weight of the ethylene propylene diene monomer (EPDM) rubber, Vulcanizing agent containing 5 parts by weight to 8 parts by weight of zinc, 1 part by weight to 2 parts by weight of the stearic acid, 1 part by weight to 3 parts by weight of the processing aid and 1 part by weight to 7 parts by weight of the calcium oxide-free (sulfur-free) ) EPDM rubber composition for weather strip.
In paragraph 14,
The vulcanizer-free (sulfur-free) EPDM rubber composition for a weather strip further comprises a moisture absorbent and a foaming agent - EPDM rubber composition for a sulfur-free weather strip.
In paragraph 17,
The vulcanizer-free (sulfur-free) EPDM rubber composition for weather strip,
EPDM rubber for a vulcanizing agent-free weather strip comprising 3 parts by weight to 5 parts by weight of the moisture absorbent and 1 part by weight to 3 parts by weight of the foaming agent with respect to 100 parts by weight of the ethylene propylene diene monomer (EPDM) rubber composition.
In paragraph 17,
The foaming agent comprises a compound represented by Formula 5 below:
[Formula 5]

In Formula 5,
X' is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or NR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group).
A glass run weather strip for automobiles manufactured using the vulcanizer-free EPDM rubber composition for weather strip according to any one of claims 1 to 19.
a) adding EPDM (ethylene propylene diene monomer) rubber, zinc oxide, stearic acid, processing aid, calcium oxide, and common additives at the same time and mixing them;
b) adding carbon black, process oil and calcium carbonate;
c) preparing a carbon master batch (CMB) composition by aging for 20 to 30 hours; and
d) adding two or more vulcanization accelerators to the CMB composition and kneading to prepare a final master batch (FMB) composition
including,
The two or more vulcanization accelerators include a compound represented by Formula 1 below,
[Formula 1]

(In Formula 1 above,
X is CR (R is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group) or a nitrogen atom,
R ¹ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,
L ¹ and L ² are each independently a substituted or unsubstituted C1 to C20 alkylene group;
n1 is an integer from 0 to 4)
The method of manufacturing a glass run weather strip for automobiles, wherein the two or more vulcanization accelerators are included in an amount of 4 parts by weight or more based on 100 parts by weight of the EPDM rubber.

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