KR20230056260A - Dynamic cross-linking thermoplastic elastomer composition with excellent durability anf storagestability and manufacturing method of automobile weather strip using the same - Google Patents

Abstract

The present invention relates to a dynamic cross-linked thermoplastic elastic body composition with excellent durability and storage stability and to an automobile weather strip manufacturing method using the same, in which a brominated alkyl phenol formaldehyde resin, where an end group is substituted with bromine by a cross-linking agent, is applied to a substrate formed of ethylene propylene diene monomer (EPDM) and polypropylene (PP) to enhance durability, while sodium gluconate is additionally input to adsorb a residual resin cross-linking agent to also enhance contamination and storage stability.

Description

Dynamic crosslinking thermoplastic elastomer composition with excellent durability and storage stability and manufacturing method of automotive weather strip using the same

The present invention relates to a dynamic crosslinking type thermoplastic elastomer composition capable of increasing EPDM crosslinking efficiency and controlling unreacted crosslinking agents to have excellent durability and storage stability, and a method for manufacturing an automotive weather strip using the same.

Recently, due to environmental pollution and depletion of petroleum resources, the release of internal combustion engine vehicles is gradually decreasing, and the launch of eco-friendly vehicles such as electric vehicles is increasing. .

On the other hand, electric cars have the advantage of almost no engine noise, but external noises such as wind noise and tire friction noise are rather loud, so high-performance sealing parts such as weather strips are required to block external noise, and eco-friendly vehicle development policy Accordingly, there is a demand for eco-friendly parts that can be recycled.

More specifically, the weather strip is a component that seals the body of a car, etc., and maintains a uniform and constant surface pressure to minimize the force required when opening and closing doors or trunks or the force when raising and lowering glass doors while performing a sealing function from the external environment. shall. The weather strip has a rubber solid form or a sponge form.

As a common material for these weather strips, EPDM (ethylene propylene diene monomer)-based thermosetting rubber with excellent weatherability is mainly used, but recently, in addition to EPDM, thermoplastic vulcanizates (TPV) are being applied. Compared to EPDM, the production process is simpler and the cost is reduced, and its application is expanding, especially for the weight reduction and recycling of automobile parts.

As a related prior art, Patent Document 1 proposes a technology for thermoplastic vulcanized rubber obtained from EPDM or conjugated diene rubber and isobutylene rubber, but the thermoplastic vulcanized rubber partially cross-linked rubber mixture is about 10 to It contains 90 parts by weight and attempts to express a modulus similar to that of vulcanized rubber while having thermoplasticity.

In other words, TPV for weather strip is a thermoplastic elastic material that has both processability of the continuous phase and rubber elasticity of the dispersed phase by dispersing EPDM cross-linked particles in PP (Poly Propylene), a thermoplastic resin that forms the continuous phase, and the characteristics of EPDM determine durability. However, the prior art as described above has problems in that the crosslinking efficiency of EPDM is insufficient and durability and storage stability are lowered due to unreacted crosslinking agents.

Patent Document 1: Korean Patent Publication No. 10-1997-0027193 "Thermoplastic vulcanized rubber obtained from EPDM or conjugated diene rubber and isobutylene rubber"

The present invention is to solve the above problems, brominated alkyl phenolformaldehyde resin whose terminal group is substituted with bromine as a crosslinking agent on a substrate made of EPDM (Ethylene propylene diene monomer) and PP (Poly propylene) It is applied to improve its durability, but the task is to also improve contamination and storage stability by adsorbing the residual resin crosslinking agent by adding sodium gluconate.

The present invention is a dynamic crosslinking thermoplastic elastomer composition, characterized in that it contains an alkylphenol formaldehyde resin whose terminal group is substituted with bromine and sodium gluconate as a crosslinking agent in a base material made of EPDM and PP, and has excellent durability and storage stability. A dynamic crosslinking type thermoplastic elastomer composition is used as a solution to the problem.

In addition, in the present invention, in a method for manufacturing a vehicle weather strip using the composition as described above, a base material made of EPDM and PP, hard carbon, an antioxidant, a processing oil, and a crosslinking agent, an alkylphenol formaldehyde resin whose terminal group is substituted with bromine, is heated to a temperature of 160° C. Putting into a twin-screw extruder at ~ 250 ° C. and mixing (S100); Adding and mixing sodium gluconate at the end of the extruder (S200); and manufacturing a vehicle weather strip by extruding or injecting the mixture (S300).

The present invention improves the durability by applying an alkylphenol formaldehyde resin whose terminal group is substituted with bromine as a crosslinking agent to a substrate made of EPDM and PP, and improves contamination and storage stability by adsorbing the residual resin crosslinking agent by additionally adding sodium gluconate. There is also an effect that can be improved.

1 is a process flow chart showing a method for manufacturing a vehicle weather strip using a dynamic crosslinking thermoplastic elastomer composition according to the present invention.

In order to achieve the above effects, the present invention relates to a dynamic crosslinking thermoplastic elastomer composition having excellent durability and storage stability and a method for manufacturing a vehicle weather strip using the same, and only parts necessary for understanding the technical configuration of the present invention are described. It should be noted that descriptions of other parts will be omitted so as not to obscure the subject matter of the present invention.

Hereinafter, a dynamic crosslinking type thermoplastic elastomer composition having excellent durability and storage stability and a manufacturing method of a vehicle weather strip using the same according to the present invention will be described in detail.

First, the dynamic crosslinking thermoplastic elastomer composition excellent in durability and storage stability according to the present invention is an alkylphenol formaldehyde resin in which an end group is substituted with bromine as a crosslinking agent in a base material made of EPDM (Ethylene propylene diene monomer) and PP (Poly propylene). (Brominated alkyl phenolformadehyde resin) and sodium gluconate.

The EPDM and PP are the substrates constituting the present invention, and are composed of 50 to 80% by weight of EPDM having an Ethylidene norbornene (ENB) content of 7 to 10% as a dispersed phase and 20 to 50% by weight of PP as a continuous phase.

Here, when the ENB is out of the above range, there is a concern that the noise blocking function may be deteriorated because the permanent compression set is not good when EPDM is used.

In addition, when the content of EDPM is less than 50% by weight and the content of PP exceeds 50% by weight, there is a concern that the permanent compression set is not good and the noise blocking function is deteriorated, and the content of EDPM exceeds 80% by weight When the content of PP is less than 20% by weight, there is a concern that moldability is not good.

The alkylphenolformaldehyde resin whose terminal group is substituted with bromine is a crosslinking agent that dynamically crosslinks EPDM and disperses it in PP, and is used in an amount of 2 to 10 parts by weight based on 100 parts by weight of the base material.

On the other hand, when using an alkylphenol formaldehyde resin in which the terminal group is not substituted with bromine, the reaction is slow, and the crosslinked EPDM may not be evenly dispersed in PP.

In addition, when the content of the alkylphenol formaldehyde resin in which the terminal group is substituted with bromine is less than 2 parts by weight, it is difficult to improve properties such as compression set, and when it exceeds 10 parts by weight, heat resistance due to residual crosslinking agent may be reduced.

The sodium gluconate is used to improve contamination and storage stability by adsorbing the residual resin crosslinking agent, and is used in an amount of 0.4 to 3 parts by weight based on 100 parts by weight of the substrate.

More specifically, the alkylphenol formaldehyde resin crosslinking agent can produce materials with excellent properties such as permanent compression set and heat resistance compared to peroxide crosslinking agents, but it is possible to manufacture materials with excellent properties such as permanent compression set and heat resistance, There are problems with aging (storage stability) and the like. Therefore, in the present invention, in order to solve this problem, 0.4 to 3 parts by weight of sodium gluconate is mixed to adsorb the residual resin crosslinking agent to improve contamination and storage stability.

Here, when the content of sodium glucosan is less than 0.4 parts by weight, there is a concern that contamination and storage stability improvement efficiency may be insufficient, and when it exceeds 3 parts by weight, there is a fear of deteriorating physical properties.

On the other hand, in the present invention, as additives, hard coal for improving physical properties, antioxidants for improving reactivity with thermoplastic elastomers and heat resistance, and processing oil for softening can be added. For example, 5 to 10 parts by weight of hard coal, antioxidants (Amin-based or phosphite-based) 0.1 to 0.2 parts by weight and 20 to 25 parts by weight of processing oil can be used, but it is not necessarily limited thereto, and has already been known in consideration of the use environment of the product or the physical properties to be achieved. Various additives and contents can be applied.

Next, as shown in FIG. 1, in the manufacturing method of the automobile weather strip according to the present invention, a substrate made of EPDM and PP, hard carbon, antioxidant, processing oil, and a crosslinking agent are used to heat an alkylphenol formaldehyde resin whose terminal group is substituted with bromine. Adding and mixing in a twin-screw extruder at 160 to 250 ° C (S100), adding and mixing sodium gluconate at the end of the extruder (S200), and extruding or injecting the mixture to manufacture a vehicle weather strip Step S300 is included.

That is, in the manufacturing method of the automobile weather strip according to the present invention, sodium gluconate is introduced from the end of the extruder as described above so that the crosslinking reaction is not disturbed and adsorbed to the remaining resin crosslinking agent after the crosslinking reaction, which causes contamination and storage. Stability can be improved.

On the other hand, since the content of each composition for each step has already been described above, it is omitted here, and extrusion or injection conditions or methods are not limited to specific conditions, and various conditions and methods that are already known can be applied depending on the type of automotive weather strip or use environment. do.

Hereinafter, the present invention will be described in more detail based on the examples below, but the present invention is not limited by the examples.

1. Manufacture of automotive weather strips

(Example 1)

Based on 100 parts by weight of a substrate composed of 75% by weight of EPDM with an ENB content of 8.9% and 25% by weight of PP, 5 parts by weight of hard coal, 0.2 parts by weight of an antioxidant (amine), 20 parts by weight of processing oil, and a crosslinking agent in which the terminal group is substituted with bromine. 6 parts by weight of an alkylphenol formaldehyde resin was added to a twin-screw extruder at a temperature of 200 ° C. and mixed (S100), while 1.2 parts by weight of sodium gluconate was additionally added at the end of the extruder and mixed (S200). Then, the mixture was prepared by injection in the form of an automobile weather strip (S300).

(Example 2)

Based on 100 parts by weight of a substrate composed of 50% by weight of EPDM and 50% by weight of PP having an ENB content of 7%, 5 parts by weight of hard coal, 0.1 part by weight of an antioxidant (amine), 20 parts by weight of processing oil, and a crosslinking agent in which the terminal group is substituted with bromine. 2 parts by weight of an alkylphenol formaldehyde resin was added to a twin-screw extruder at a temperature of 160 ° C. and mixed (S100), while 0.4 parts by weight of sodium gluconate was additionally added at the end of the extruder and mixed (S200). And the mixture was prepared by extruding in the form of a car weather strip (S300).

(Example 3)

Based on 100 parts by weight of a substrate composed of 80% by weight of EPDM with an ENB content of 10% and 20% by weight of PP, 10 parts by weight of hard coal, 0.2 parts by weight of an antioxidant (amine), 25 parts by weight of processing oil, and a crosslinking agent in which the terminal group is substituted with bromine. 10 parts by weight of an alkylphenol formaldehyde resin was added to a twin-screw extruder at a temperature of 250 ° C. and mixed (S100), while 3 parts by weight of sodium gluconate was additionally added at the end of the extruder and mixed (S200). Then, the mixture was prepared by injection in the form of an automobile weather strip (S300).

(Comparative Example 1)

It was prepared in the same way as in Example 1, but sodium gluconate was not added.

(Comparative Example 2)

It was prepared in the same way as in Example 2, but sodium glucosanate was not added.

(Comparative Example 3)

It was prepared in the same manner as in Example 1, but sodium gluconate was not added, and 1.0 parts by weight of dicumyl peroxide was mixed as a crosslinking agent.

2. Evaluation of automotive weather strips

(1) durability

Durability, such as physical properties and heat resistance, was evaluated for the examples and comparative examples, and the test criteria and results are shown in [Table 1] below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 test
standard Hardness (A type) 78 78 78 78 80 80 ASTM D-224 importance 0.92 0.92 0.92 0.92 0.92 0.92 ASTM D-792 permanent compression set
(70℃×22 hours, %) 25 24 24 25 26 36 KS-M6660 Tensile strength (kgf/cm ² ) 80 80 80 75 75 82 ASTM D-412 heat resistance
[150℃×168 hours] Tensile strength (kgf/cm ² ) 74 74 74 64 64 45 ASTM D-412 Change rate (%) -7.5 -7.5 -7.5 -14.7 -14.7 -45.1 -

(2) storage stability

Storage stability was evaluated for the above examples and comparative examples, and the test criteria and results are shown in [Table 2] and [Table 3] below.

division Example 1 Example 2 Example 3 day 1 week later 2 weeks later 3 weeks later 4 weeks later day 1 week later 2 weeks later 3 weeks later 4 weeks later day 1 week later 2 weeks later 3 weeks later 4 weeks later permanent compression set
(70℃*?*time, %)
KS-M6660 25 24 25 26 25 24 24 25 25 26 25 24 25 26 25 Tensile strength (kgf/cm ² )
ASTM D-412 80 82 81 82 81 80 81 82 81 80 80 81 81 81 82

division Comparative Example 1 Comparative Example 2 Comparative Example 3 day 1 week later 2 weeks later 3 weeks later 4 weeks later day 1 week later 2 weeks later 3 weeks later 4 weeks later day 1 week later 2 weeks later 3 weeks later 4 weeks later permanent compression set
(70℃*?*time, %)
KS-M6660 25 28 31 36 45 26 29 30 34 44 36 39 41 44 51 Tensile strength (kgf/cm ² )
ASTM D-412 75 72 68 62 54 75 74 69 67 60 82 78 68 66 59

As shown in [Table 1] and [Table 2], it can be seen that the automobile weather strip according to the embodiment of the present invention has excellent durability and improved storage stability compared to the comparative example.

As described above, the dynamic crosslinking type thermoplastic elastomer composition excellent in durability and storage stability according to a preferred embodiment of the present invention and the manufacturing method of a vehicle weather strip using the same have been described according to the above description and drawings, but this is for example Those skilled in the art will be able to understand that various changes and modifications are possible without departing from the technical spirit of the present invention.

Claims (3)

In the dynamic crosslinking thermoplastic elastomer composition,
It is characterized in that it contains brominated alkyl phenolformaldehyde resin and sodium gluconate in which the end group is substituted with bromine as a crosslinking agent on a base material made of EPDM (Ethylene propylene diene monomer) and PP (Poly propylene) A dynamic crosslinking thermoplastic elastomer composition with excellent durability and storage stability.
According to claim 1,
The dynamic crosslinking thermoplastic elastomer composition,
5 to 10 parts by weight of hard coal, 0.1 to 0.2 parts by weight of antioxidants, 20 parts by weight of processing oil, based on 100 parts by weight of a substrate composed of 50 to 80% by weight of EPDM with 7 to 10% of Ethylidene norbornene (ENB) and 20 to 50% by weight of PP. ~ 25 parts by weight, 2 to 10 parts by weight of an alkylphenol formaldehyde resin whose terminal group is substituted with bromine as a crosslinking agent, and 0.4 to 3 parts by weight of sodium gluconate, a dynamic crosslinking type thermoplastic with excellent durability and storage stability. elastomer composition.
In the method for manufacturing a vehicle weather strip using the composition according to claim 1,
A base material made of EPDM and PP, hard carbon, antioxidant, processing oil, and an alkylphenol formaldehyde resin whose terminal group is substituted with bromine as a crosslinking agent are put into a twin-screw extruder at a temperature of 160 to 250 ° C. and mixed (S100);
Adding and mixing sodium gluconate at the end of the extruder (S200); and
A method for manufacturing a vehicle weather strip, characterized in that it comprises: extruding or injecting the mixture to manufacture a vehicle weather strip (S300).

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