KR100644256B1 - The coating material for car weatherstrip and a process for preparing the same - Google Patents

Abstract

The present invention relates to a coating material for automobile weather strip and a method of manufacturing the same. More specifically, (a) 20 to 80% by weight of HDPE (High Density Polyethylene) of 300,000 or more and (b) HDPE 80 to 150,000 to 250,000 of average molecular weight (Mw) based on the total weight of the resin composition as the main component. A polyethylene resin composition containing 20% by weight and containing 0.05 to 1.0 parts by weight of a crosslinking agent and 0.05 to 1.0 parts by weight of a reaction terminator based on 100 parts by weight of the main component is prepared by reactive extrusion. This provides a coating material suitable for various shapes and applications at low cost.

Reaction extrusion method * Polyethylene resin composition * Weather strip * Coating material

Description

Coating material for car weather strip and manufacturing method thereof {The coating material for car weatherstrip and a process for preparing the same}

The present invention relates to a coating material for automobile weather strip and a method of manufacturing the same. More specifically, (a) 20 to 80% by weight of HDPE (High Density Polyethylene) of 300,000 or more and (b) HDPE 80 to 150,000 to 250,000 of average molecular weight (Mw) based on the total weight of the resin composition as the main component. A polyethylene resin composition containing 20% by weight and containing 0.05 to 1.0 parts by weight of a crosslinking agent and 0.05 to 1.0 parts by weight of a reaction terminator based on 100 parts by weight of the main component is prepared by reactive extrusion. This provides a coating material suitable for various shapes and applications at low cost.

Thermosetting crosslinked ethylene propylene diene terpolymer (EPDM), which has been used as a conventional automotive weather strip, has used a method of adhering nylon yarn to a contact portion in order to reduce frictional resistance with automotive glass and improve wear resistance. However, the above method has a disadvantage in that the manufacturing process is too complicated and the defective rate is high to increase the manufacturing cost.

Recently, in order to compensate for the disadvantages of the long molding process and low productivity due to the manufacturing characteristics of the thermosetting crosslinked EPDM, a thermoplastic crosslinked elastomer TPV (Thermoplastic Vulcanizates) is used to replace automotive weather strips. There is a problem that a separate coating process is required to reduce frictional resistance and improve wear resistance.

On the other hand, the coating material used is a resin composition using ionomer, UHMW (Ultra High Molecular Weight) HDPE (High Density Polyethylene) developed by Axwa, such as Himilan commercially available from Mitsui Dupont, Japan. HDPE-based resin polymerized product (Spec. No. 0150251) to be included, TPV material for coating materials modified existing TPV material, and the like.

However, to form a weather strip for automobiles by extrusion molding from two extruders to one mold (190 ° C.) using TPV resin and HDPE-based coating material to form a weather strip main body having a press-contacted portion in contact with the window glass. In case of No. 0150251 regarding the manufacturing method, low frictional resistance with glass and excellent abrasion resistance, UHMW HDPE is hard to be melted by heat, so it is difficult to mix with general compounding technology, so it is manufactured only through series polymerization in HDPE polymerization process. Due to this, it is difficult to produce a variety of products, and there is a disadvantage in that the cost is very high as a mixture of UHMW HDPE and HDPE through polymerization.

In addition, the resin composition using the ionomer has a good surface appearance as a blend of HDPE and Ionomer, but has a disadvantage in that the perturbation and wear resistance are inferior to that of the HDPE system and the gloss is high, thereby making it inconsistent with other components.

In addition, the high hardness TPV-based coating material to improve the wear resistance is similar to the material of the existing TPV with a lubricant added, there is a disadvantage that the durability is poor due to weak perturbation and wear resistance.

Accordingly, the present inventors have studied to develop a coating material having low friction resistance and excellent wear resistance while solving the above problems. As a result, UHMW HDPE and a wide molecular weight distribution in a general compounding extruder using reactive extrusion When manufacturing an HDPE resin composition having a low frictional resistance, excellent wear resistance, and easy to control molecular weight distribution and flowability unlike conventional HDPE-based polymer products, it is found that a variety of products can be produced at low cost and completed the present invention. It was.

Accordingly, it is an object of the present invention to provide a method for producing HDPE coating material for automobile weather strip having excellent perturbation and wear resistance.

In addition, another object of the present invention is to provide a HDPE-based coating material prepared using the above method with a polyethylene resin composition.

In order to achieve the above object, the coating material for automobile weather strip of the present invention is (a) 20 to 80% by weight of HDPE (High Density Polyethylene) of (Aw) average molecular weight (Mw) of 300,000 or more based on the total weight of the resin composition as a main component and (b) Polyethylene containing 80 to 20% by weight of HDPE having an average molecular weight (Mw) of 150,000 to 250,000 and containing 0.05 to 1.0 part by weight of (c) crosslinking agent and 0.05 to 1.0 part by weight of (c) reaction terminator based on 100 parts by weight of the main component. It is characterized in that it is prepared using a resin composition. Particularly, in order to reinforce the function of the coating material in the components (a) to (d), (e) a coating material for automotive weather strips containing 5 to 20 parts by weight based on 100 parts by weight of PTFE (polytetrafluoroethylene) may be prepared. have.

In the present invention, it is possible to manufacture a coating material for automotive weather strip having excellent specificity by using a reactive extrusion method according to the composition. That is, the present invention provides a coating material suitable for various product uses and shapes by producing a coating material using a polyethylene resin composition using a reaction extrusion method at low production costs.

Hereinafter, more detailed description of the present invention.

The polyethylene resin composition according to the present invention comprises (a) 20 to 80% by weight of HDPE (High Density Polyethylene) of 300,000 or more, and (b) HDPE of 150,000 to 250,000, based on the total weight of the resin composition as a main component. It contains 80 to 20 weight% and consists of 0.05-1.0 weight part of (c) crosslinking agents and 0.05-1.0 weight part of reaction terminators with respect to 100 weight part of said main components.

In particular, PTFE (polytetrafluoroethylene) represented by the following formula (1) to the components (a) to (d) is added to the side injector in an amount of 5 to 20 parts by weight based on 100 parts by weight of the main component. By further containing PTFE used in the present invention, the appearance and wear resistance of the coating material can be further improved.

-[CF ₂ -CF ₂ ] _n-

The crosslinking agent is a peroxide crosslinking agent, and specifically, at least one selected from benzoyl peroxide, dicumyl peroxide, isobutyryl peroxide, 2,2-bis (t-butylperoxy) butane and the like. The initiator is preferably used in the form of a master batch diluted in polyethylene or polypropylene for the stability of the reaction, and a crosslinking masterbatch (PP (mixed with 20 parts by weight of benzoyl peroxide to 80 parts by weight of polypropylene as a peroxide-based crosslinking agent). 80%) / Peroxide (20%) Masterbatch) is preferred.

On the other hand, as the reaction terminator, phenolic oxidative stabilizers, phosphorus oxidative stabilizers, phosphite-based thermal stabilizers, etc. which are generally used may be used, and phenol-based primary and secondary composite oxidative stabilizers are preferable.

Method for manufacturing a coating material for automotive weather strip of the present invention using a twin screw extruder (L / D) of 32 or more, (a) at least one HDPE (High Density Polyethylene) of average molecular weight (Mw) 300,000 or more and ( c) Compounding the crosslinking agent into the main feeder first, (b) one or more HDPEs with an average molecular weight (Mw) of 150,000 to 250,000, and (d) adding a reaction terminator to the side feeder. do. At this time, the reaction temperature is suitable 180 ~ 220 ℃.

In particular, (e) when the coating material is added to the side injector in an amount of 5 to 20 parts by weight with respect to 100 parts by weight of the main component improves the appearance and wear resistance of the coating material.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited only to these examples.

Example 1

To prepare Example 1 with the composition shown in Table 1, first, the components (a) and (c) to the main injector using a twin screw extruder, and then the components (b) and (d) to the side injector Prepared by pounding. At this time, the twin-screw extruder set temperature is 190 ~ 210 ℃, the reaction time was 45 ~ 60s.

Example 2

To the composition of Table 1 was prepared in the same manner as in Example 1.

Example 3

To prepare Example 1 with the composition shown in Table 1, first using the twin screw extruder component (a) and (c) to the main injector, then components (b), (d) and (e) to the side injector Was prepared by compounding. At this time, the twin-screw extruder set temperature is 190 ~ 210 ℃, the reaction time was 45 ~ 60s.

ingredient Example 1 (content; parts by weight) Example 2 (content; parts by weight) Example 3 (content; weight part) (a) HDPE (Mw: 380,000, MWD: 35) 50 HDPE (Mw: 320,000, MWD: 35) 15 HDPE (Mw: 320,000, MWD: 35) 20 HDPE (Mw: 400,000, MWD: 10) 15 HDPE (Mw: 400,000, MWD: 10) 20 (b)                                              HDPE (Mw: 240,000, MWD: 18) 50 HDPE (Mw: 200,000, MWD: 25) 70 HDPE (Mw: 200,000, MWD: 25) 60 (c) PP + Peroxide master batch 0.5 PP + Peroxide master batch 0.1 PP + Peroxide master batch 0.2 (d) Phenolic 1,2-Compound Oxidation Stabilizer 0.5 Phenolic 1,2-Compound Oxidation Stabilizer  0.5 Phenolic 1,2-Compound Oxidation Stabilizer  0.5 (e) PTFE 10

 [Comparative Examples 1-3]

Comparative Examples 1 to 3 were selected from the existing commercialized coating materials, Comparative Example 1 HDPE-based coating material TM-80 (Mitsui), Comparative Example 2 Ionomer-based coating material HIMILAN (Mitsui-DuPont, HM-2508BK), Comparative Example 3 was used to select a TPE-based high hardness coating material (AES, Santoprene 123-52).

[Test Example]

In order to evaluate the performance of the Examples 1 to 3 and Comparative Examples 1 to 3, ① surface appearance, ② friction coefficient, ③ wear resistance test 1, ④ wear resistance test 2, and ⑤ cold resistance heat cycle was performed. The test of the above ① ~ ⑤ will be described in more detail below.

① Surface appearance evaluated the appearance of the product when the coating material was molded in the weather strip manufacturing process commercialized in automobiles.

② Friction coefficient and static friction coefficient were measured under conditions of speed (15cm / min), weight of test weight (200g), temperature (23 ℃) and humidity (50%).

③ Abrasion resistance test 1 evaluated the durability of the coating material while repeating the glass sandwiched between the molded weather strip.

④ Abrasion resistance test 2 shows the worn content of the coating material after rotating 2500 times at a speed of 70 RPM with a load of 1 kg on the wear wheel.

⑤ Cold-resistant heat cycle test is to check the motor load and the coating material wear condition while the molded weather strip is mounted on the car, and the vehicle glass is repeatedly operated up and down under cold-proof (-30 ℃), room temperature and heat-resistant condition (80 ℃). It was.

The results are shown in Table 2 below.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 HDPE (high molecular weight) 50 30 40 HDPE-based polymer (UHMW HDPE + general HDPE) PE / Ionomer High Hardness TPV System HDPE (Low Molecular Weight) 50 70 60 Crosslinking agent 0.5 0.1 0.2 Oxidation stabilizer 0.5 0.5 0.5 PTFE 10 MI 0.11 0.35 0.30 0.25 1.2 1.5 density 0.96 0.96 0.96 0.96 0.95 0.94 Hardness 65D 67D 67D 65D 45D 50D Surface appearance Matte, Emboss Matte, Emboss Some gloss, emboss Matte, Emboss Polished, smooth Polished, projection Coefficient of friction (static friction) 0.25 0.23 0.17 0.23 1.16 0.65 Coefficient of Friction (Dynamic Friction) 0.22 0.21 0.16 0.20 0.70 0.52 Abrasion Resistance Test 1 1,000,000 or more 1,000,000 or more 1,500,000 or more 1,000,000 or more 500,000 ~ 700,000 300,000 ~ 500,000 Abrasion Resistance Test 2 0.007 0.009 0.006 0.018 0.025 0.080 Cold-resistant heat cycle clear clear clear clear Coating Worn Coating Worn

As shown in Table 2, in the case of surface appearance evaluation, Examples 1 to 3 and Comparative Example 1 produced natural embossing during the forming and cooling process, and Comparative Example 2 had the highest glossiness and the surface of the five coating materials. It was smooth, and Comparative Example 3 was glossy but it was confirmed that there is a small projection on the surface.

In addition, the friction coefficient of Examples 1 to 3 according to the present invention was confirmed that the embossing produced in the molding process has a relatively low friction coefficient value because it has an effect of reducing the surface area.

In addition, in the wear resistance test 1, Examples 1 to 3 and Comparative Example 1, the surface state of the coating material is good even after reciprocating 1,000,000 times, while Comparative Example 2, although there is a deviation between the test specimens, the coating material was completely worn within 700,000 times, Comparative Example 3 was found to wear within 500,000 times.

On the other hand, in the wear resistance test 2 Examples 1 to 3 are worn out and lost content is less than 50% compared to Comparative Examples 1 and 2, compared with Comparative Example 3 confirmed that only about 10% of the wear is relatively excellent durability Can be.

In addition, in the cold cycle test, Examples 1 to 3 and Comparative Example 1 did not find any abnormal symptoms, Comparative Examples 2 to 3 it can be confirmed that the motor load rise and the coating material peeling phenomenon occurred. In particular, in the case of Example 3 containing the component (e) PTFE it was confirmed that the overall appearance of the product is shiny while the wear resistance is improved.

In summary, it can be seen that Examples 1 to 3 according to the present invention exhibit superior friction characteristics and durability compared to Comparative Examples 1 to 3, which are conventional coating materials.

As described above, the automotive weather strip coating material according to the present invention can provide a coating material having a high long-term reliability with excellent friction characteristics and durability while significantly reducing the manufacturing cost compared to the conventional coating material commercially available.

Claims (7)

It contains (a) 20 to 80 wt% of HDPE (High Density Polyethylene) of 300,000 or more and (b) 80 to 20 wt% of HDPE of 150,000 to 250,000 of average molecular weight (Mw) based on the total weight of the resin composition. and, A polyethylene resin composition comprising (c) 0.05 to 1.0 parts by weight of crosslinking agent and 0.05 to 1.0 parts by weight of reaction terminator based on 100 parts by weight of the main component, Reactive extrusion involves first injecting at least one component (a) and (c) crosslinking agent into the main feeder using a twin screw extruder with an L / D of 32 or more, and then 1 In the manufacturing method of the coating material for automotive weather strip, characterized in that the compound (b) and (d) reaction terminator is added to the side feeder (compounding) to produce a compound (compounding), (C) the crosslinking agent is at least one selected from the group consisting of benzoyl peroxide, dicumyl peroxide, isobutyryl peroxide, and 2,2-bis (t-butylperoxy) butane, Wherein (d) the reaction terminating agent is a method for producing a coating material for automotive weather strip, characterized in that at least one selected from the group consisting of phenolic oxidative stabilizer, phosphorus oxidative stabilizer and phosphite (Phosphite) thermal stabilizer. It contains (a) 20 to 80 wt% of HDPE (High Density Polyethylene) of 300,000 or more and (b) 80 to 20 wt% of HDPE of 150,000 to 250,000 of average molecular weight (Mw) based on the total weight of the resin composition. and, A polyethylene resin composition comprising (c) 0.05 to 1.0 parts by weight of crosslinking agent, 0.05 to 1.0 parts by weight of reaction terminator, and 5 to 20 parts by weight of (e) PTFE (polytetrafluoroethyelen) based on 100 parts by weight of the main component, Reactive extrusion involves first injecting at least one component (a) and (c) crosslinking agent into the main feeder using a twin screw extruder with an L / D of 32 or more, and then 1 In the method of manufacturing a coating material for automotive weather strip, characterized in that the compound (b), (d) reaction terminator, and (e) PTFE is added to a side feeder to compound the compound (compounding). , (C) the crosslinking agent is at least one selected from the group consisting of benzoyl peroxide, dicumyl peroxide, isobutyryl peroxide, and 2,2-bis (t-butylperoxy) butane, Wherein (d) the reaction terminating agent is a method for producing a coating material for automotive weather strip, characterized in that at least one selected from the group consisting of phenolic oxidative stabilizer, phosphorus oxidative stabilizer and phosphite (Phosphite) thermal stabilizer. delete The method according to claim 1 or 2, wherein the crosslinking agent is used in the form of a masterbatch in which a peroxide-based crosslinking agent is diluted in polyethylene or polypropylene. delete It contains (a) 20 to 80% by weight of HDPE (High Density Polyethylene) of 300,000 or more and (b) 80 to 20% by weight of HDPE of 150,000 to 250,000 of average molecular weight (Mw) based on the total weight of the resin composition. and, A polyethylene resin composition comprising (c) 0.05 to 1.0 parts by weight of crosslinking agent and 0.05 to 1.0 parts by weight of reaction terminator based on 100 parts by weight of the main component, Coating material for a vehicle weather strip, characterized in that produced by the method of claim 1. It contains (a) 20 to 80% by weight of HDPE (High Density Polyethylene) of 300,000 or more and (b) 80 to 20% by weight of HDPE of 150,000 to 250,000 of average molecular weight (Mw) based on the total weight of the resin composition. and, A polyethylene resin composition comprising (c) 0.05 to 1.0 parts by weight of a crosslinking agent, 0.05 to 1.0 parts by weight of a reaction terminator, and (e) 5 to 20 parts by weight of PTFE (polytetrafluoroethylene) based on 100 parts by weight of the main component, Coating material for a vehicle weather strip, characterized in that the manufacturing method of claim 2.