KR20230078071A - Thermoplastic resin composition for automobile interior using nano metal salt and molded article using the same - Google Patents

Abstract

The present invention is a polypropylene resin; and a mixture of a rubber composition, wherein the rubber composition relates to a thermoplastic resin composition for automobile interior materials including an unsaturated rubber functionalized with a polar group and nano metal ions.

Description

Thermoplastic resin composition for automobile interior using nano metal salt and molded article using the same

The present invention relates to a thermoplastic resin composition for automobile interior materials having excellent mechanical properties and a molded article using the same.

In general, car interior materials such as door trim, dash board, instrument panel, console, floor carpet, etc. are used to provide comfort, luxury, and body contact A material capable of imparting an excellent tactile sensation to the part is used. In particular, polyvinyl chloride (PVC), resin, and rubber materials, which have advantages of excellent processability, low unit price, and appropriate mechanical and physical properties, have been widely used. However, in the case of PVC 　 resin, the use of additives such as plasticizers is essential, and this causes dioxin and volatile organic compounds (VOCs), which are harmful substances, to be generated during molding, and there is a problem that the elastic restoring force to be implemented as 　car 　interior material is poor, Its usage is gradually decreasing. In addition, in the case of rubber, it is impossible to recycle due to sulfur crosslinking, and its high specific gravity does not fit the recent trend to improve fuel efficiency, so replacement with other new materials is required.

For example, Patent Document 1 (Korean Laid-Open Patent Publication No. 10-2008-0069364) discloses an organic peroxide-based crosslinking agent, crosslinking aid, and scratch resistance additive in a basic “resin” composition consisting of polypropylene “resin,” “thermoplastic” elastomer, processing oil, and inorganic filler. The olefin-based "thermoplastic" resin "composition" is described. However, in the case of the 　thermoplastic 　resin composition according to Patent Document 1, the permanent compression set is high and the elastic restoring force is low, and the scratch resistance is insufficient to be used as an unpainted material for 　cars　interior materials. There is a problem. Automotive interior materials are manufactured with or without painting and applied to the final product. When the painting method is applied, the cost of automobile parts increases and environmental issues arise. Therefore, there is an increasing demand for injection methods and materials that do not require a separate painting process to reduce processes and production costs. However, since unpainted materials are very vulnerable to problems such as easy scratches on the surface by occupants, the demand for materials with improved scratch resistance has further expanded.

Accordingly, as a "polypropylene" resin "composition with excellent scratch resistance", Patent Document 2 (Korean Patent Publication No. 10-2013-0070428) is a highly crystalline polypropylene having an isotactic peptide fraction of 96% or more by C-NMR method Resin (High Isotacticity Polypropylene, HIPP) 40 to 98% by weight; 1 to 30% by weight of rubber component; And a polypropylene "resin" composition containing 1 to 30% by weight of polypropylene nano masterbatch is described. However, in the case of the polypropylene "resin" composition according to Patent Document 2, the scratch resistance is somewhat improved, but the permanent compression set is high, resulting in a low elastic restoring force.

In addition, Patent Document 3 (Korean Patent Publication No. 10-2021-0052748) discloses 80 to 90 parts by weight of ethylene propylene diene monomer (EPDM), 30 to 50 parts by weight of polybutene (PB),

30 to 40 parts by weight of polypropylene (PP), 110 to 130 parts by weight of paraffin oil having a kinematic viscosity at 40 ° C. of 170 cSt or more, and 0.7 to 0.9 parts by weight of a peroxide crosslinking agent;

Disclosed is an extruded sheet for automotive interior materials comprising 0.5 to 0.8 parts by weight of an antioxidant and 0.4 to 0.6 parts by weight of an additive selected from a crosslinking aid, a lubricant, a polypropylene wax, and a filler. The extruded sheet for automobile interior materials has the advantage of being harmless to the human body and harmless to recycling or incineration, but still lacks scratch resistance and mechanical strength, and has low physical properties of rubber, so there is a limit to increasing the rubber content. There are downsides.

Patent Document 4 (Korean Patent Registration No. 10-1187712) discloses (A) 20 to 74.8 parts by weight of polyolefin, (B) 10 to 30 parts by weight of thermoplastic rubber, (C) 15 to 30 parts by weight of inorganic filler,

(D) 0.1 to 10 parts by weight of a polyamide slip agent, and

(E) A polyolefin "resin" composition comprising 0.1 to 10 parts by weight of fluororesin is disclosed. The polyolefin resin composition has improved scratch resistance due to the addition of a fluororesin.

On the other hand, when the content of rubber in the automotive interior material composition increases, a luxurious and soft touch can be imparted, but as the amount of rubber increases, the stiffness, heat resistance, and above all, deterioration in scratch resistance cannot be avoided. In addition to the production process, the user's hand touches a lot during the transportation process and use period, resulting in appearance damage and whitening that occurs during the production process.

Patent Document 1: Korean Patent Publication No. 10-2008-0069364

Patent Document 2: Korean Patent Publication No. 10-2013-0070428

Patent Document 3: Korean Patent Publication No. 10-2021-0052748

Patent Document 4: Korean Patent Registration No. 10-1187712

Therefore, in order to solve the above problems, the present invention is to provide a thermoplastic resin composition for automobile interior materials that can provide a soft touch while having excellent mechanical strength, and a molded article using the same.

The present invention (a) a polypropylene resin; and (b) a thermoplastic resin composition for automotive interior materials comprising a mixture of a rubber composition, wherein the rubber composition includes an unsaturated rubber functionalized with a polar group and nano metal ions.

The "thermoplastic" resin composition according to one embodiment of the present invention and molded products using the same have excellent mechanical strength such as hardness, tensile strength, and scratch resistance, moldability, and elasticity, and can be usefully applied for applications such as automobile interior materials.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

According to the present invention, (a) a propylene resin; and (b) a rubber composition, wherein the rubber composition includes an unsaturated rubber functionalized with a polar group and nano metal ions.

Hereinafter, each component included in the “thermoplastic” “resin” composition will be described in detail.

(a) propylene resin

Polypropylene "resin" includes random "polypropylene, homo" polypropylene, or both.

The homo polypropylene is a polymer polymerized only with propylene, and can realize characteristics such as high stereoregularity, rigidity, and excellent heat resistance. Specifically, the homo-polypropylene may have a flexural modulus of about 13,000 kg/cm 2 to about 17,000 kg/cm 2 according to ASTM D 790. The thermoplastic "resin" composition includes homo "polypropylene having a flexural modulus within the above range, and may simultaneously have excellent" hardness and elongation.

The random polypropylene is a polymer whose stereoregularity is lowered by copolymerizing propylene and a small amount of other olefins, and has more amorphous parts than homopropylene, so its rigidity is slightly lower, but it serves to impart impact 　 strength 　 and flexibility . The random polypropylene may have a melt index of about 0.2 g/10 min to about 0.3 g/10 min according to ASTM D 1238. In addition, the random polypropylene may have an elongation of about 600% or more according to ASTM D 638. In addition, the random polypropylene may have a flexural modulus of about 8,000 kg/cm 2 to about 9,000 kg/cm 2 according to ASTM D 790. The thermoplastic "resin" composition is a random "polypropylene having the characteristics of the above range (b) When included with a rubber composition, it has excellent moldability, provides soft sensibility, and provides excellent mechanical properties required as an automobile interior material.

(b) rubber composition

The thermoplastic resin composition of the present invention includes a rubber composition in order to impart a soft touch feeling.

The rubber composition includes an unsaturated rubber functionalized with a polar group and a nano-metal, wherein the nano-metal forms an ionic bond with a polar group connected to the unsaturated rubber and forms an ion cluster between unsaturated rubber molecules by an ion-ion interaction. do. These ionic bonds have a very strong binding force compared to hydrogen bonds or covalent bonds, and improve mechanical properties of the thermoplastic resin composition.

The unsaturated rubber is modified with a polar group capable of ionic bonding, and in one embodiment, it may be obtained by reacting the unsaturated rubber with the addition of an initiator together with the polar group.

More specifically, a functionalized unsaturated rubber may be obtained by reacting 1 to 20 parts by weight of a polar group with respect to 100 parts by weight of an unsaturated rubber. The polar group is (meth)acrylic acid, maleic acid; fumaric acid; crotonic acid; Itaconic acid, sulfonic acid or their anhydrides are included, and the (meth)acrylic acid includes acrylic acid, methacrylic acid, methyl acrylic acid, methyl methacrylic acid, ethyl acrylic acid, ethyl methacrylic acid, butyl acrylic acid and butyl methacrylic acid. etc. are included. The polar group is preferably (meth)acrylic acid, more preferably acrylic acid.

The unsaturated rubber means a rubber containing an unsaturated group, for example, a group consisting of polyisoprene rubber, polybutadiene rubber, ethylene propylene diene EPDM rubber, styrene butadiene rubber, and acrylonitrile butadiene rubber. It may be one or more selected from. Preferably, the unsaturated rubber is EPDM rubber.

The rubber composition may be prepared by mixing 1 to 30 parts by weight of nano metal ions with respect to 100 parts by weight of an unsaturated rubber functionalized with a polar group. More preferably, 1 to 10 parts by weight of nano metal ions may be included. When the nano-metal within the above numerical range is included, an ion cluster may be formed through ionic bonding with a polar group. On the other hand, when the content of nano-metal ions is less than 1 part by weight, it is difficult to improve mechanical properties compared to conventional rubber compositions because ionic bonds with unsaturated rubber are not formed, and when it exceeds 30 parts by weight, dispersibility decreases and physical properties deteriorate. there is a risk of

The nano-metal may be lithium, sodium, magnesium or zinc, and particularly preferably lithium and sodium metal. When nano-sized lithium and sodium metals are used, the effects of tensile strength, compression set, scratch resistance and embossability are remarkably improved compared to other metals.

The size of the nano-metal silver particles is 10 to 900 nm, preferably 30 to 500 nm. Since the nano-metal of the present invention has a nano size of 10 to 900 nm, the dispersibility of the rubber composition is significantly improved, and thus the mechanical properties and scratch resistance of the thermoplastic resin composition are improved and used for automobiles, electronics, or energy industries. available as material. On the other hand, if the particle size is less than 10 nm, the fine particles aggregate well with each other, reducing the effect of the mechanical properties and scratch resistance, and reducing workability such as dust blowing. difficult to differentiate.

In one embodiment of the present invention, the rubber composition may additionally include at least one additive selected from an initiator, a crosslinking agent, an antioxidant, a lubricant, a catalyst, and a UV stabilizer.

The initiator is a material for initiating a polymerization reaction, preferably a functionalization reaction of the rubber composition, and any initiator commonly used in the art for this purpose may be used, preferably t-butyl cumyl peroxide, benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di(t-butyl peroxy)hexane, di-t-butyl per It is preferred to use oxide, t-butylperoxy benzoate, a,a-bis(t-butyl peroxy isopropyl)benzene, di-isopropylbenzene or mixtures thereof. In addition, it is preferable to use 0.05 to 1.0 parts by weight of the initiator based on the total weight of the rubber composition. If the initiator is less than 0.05 parts by weight, sufficient reaction does not occur, and if it is more than 1.0 parts by weight, there is a problem that protrusion may occur due to overreaction, so it is good to use it within the above range.

The crosslinking agent is for forming a three-dimensional network structure by forming chemical bonds between several specific atoms in the unsaturated rubber. 3,5-trimethylcyclohexane (TMC), n-butyl-4,4-(bis-butyl peroxy) valerate (TVP), dicumyl peroxide (DCP), 1,1-bis (t-butyl peroxy) -Diisopropylbenzene (BPPB), benzoyl peroxide (BPO), t-butylperoxybenzoate (Z), di-t-butylperoxide (DTBP), 2,5-dimethyl-2,5-di- There are t-butylperoxyhexane (25B), 2,5-di methyl-2,5-di-t-butylperoxylhexene-3 (hexyne-3), etc., but any crosslinking agent commonly used in the art is limited can be used without being

The antioxidant is included in phenol-based antioxidants, benzoimidazole-based, and amine-based antioxidants, and any antioxidant commonly used in the art may be used without limitation.

The lubricant is intended to increase processability by reducing the viscosity of the rubber composition, and may be used by mixing one or two phases of a wax type, such as PE wax and paraffin wax, and a stearic acid type, such as magnesium stearate and calcium stearate. . In addition, it is preferable to use 0.5 to 2.0 parts by weight of the lubricant based on the total weight of the resin composition. If the lubricant is less than 0.5 parts by weight, processability is poor, and if it is greater than 2.0 parts by weight, uniform dispersion may be hindered, so use within the above range. It is good to do.

The catalyst is a catalyst for the crosslinking reaction of the rubber composition, and is not particularly limited as long as it is a catalyst commonly used in the industry for this purpose, but is preferably used in an amount of 0.5 to 3.0 parts by weight, and the amount used is the rubber. It is preferable to use 0.5 to 5.0 parts by weight based on the total weight of the composition. If the catalyst is less than 0.5 parts by weight, there is a problem that it does not play a sufficient role as a crosslinking catalyst, and if it is more than 5.0 parts by weight, crosslinking is not even and side reactions may occur, so it is good to use it within the above range.

The UV stabilizer may be used without limitation as long as it is a material commonly used in the art, and it is preferable to use 0.5 to 50 parts by weight based on 100 parts by weight based on the total weight of the rubber composition. If the amount of the UV stabilizer is less than 0.5 parts by weight, it is difficult to expect a sufficient UV stabilization effect, and if it exceeds 5.0 parts by weight, the UV stabilizer effect due to excessive use is no longer present and may cause degradation of the performance of the thermoplastic resin, as well as increase in cost Since it also becomes a factor, it is used within the above range.

In one embodiment of the present invention, the thermoplastic resin composition (a) 30 to 70 parts by weight of a propylene resin; and (b) 70 to 30 parts by weight of the rubber composition. More preferably, the thermoplastic resin composition includes about 40 parts by weight of a propylene resin; and (b) about 60 parts by weight of the rubber composition. It has a certain level of hardness and high scratch resistance along with excellent formability satisfying the above range. On the other hand, the embossability of the molded article prepared from the thermoplastic resin composition is very poor, and both scratch resistance and hardness are reduced.

Hereinafter, specific embodiments of the present invention are presented. However, the embodiments described below are only intended to specifically illustrate or explain the present invention, and the present invention should not be limited thereto.

One. Preparation of thermoplastic resin composition

Example 1

(Preparation of rubber composition):

An unsaturated rubber was modified by mixing EPDM, an initiator, and a polar group according to the composition shown in Table 1, and then a metal ion having a size of 100 nm was added to prepare a rubber composition. This rubber composition was reaction-extruded with a twin-screw extruder.

(Preparation of thermoplastic resin composition):

A thermoplastic resin composition was prepared by mixing the prepared rubber composition and a propylene resin composition (H7900 from LG Ghem) at 60 parts by weight and 40 parts by weight, respectively.

Examples 2 to 6

A thermoplastic resin composition was prepared in the same manner as in Example 1, except that the composition ratio was changed as shown in Table 1, and lithium, sodium, magnesium, and zinc were used as neutralizing metals.

Comparative Example 1

Shore A prepared in the step of dynamically crosslinking with a twin-screw extruder by adding polypropylene resin as a continuous phase and rubber as a dispersed phase in a constant ratio and adding other additives to it. A thermoplastic elastomer having MFR) of 5 g/10 min was prepared.

Comparative Examples 2 to 5

A thermoplastic resin composition was prepared in the same manner as in Example 1, except that 100 μm-sized lithium, sodium, magnesium, and zinc were used instead of the 100-nm-sized lithium metal.

2. Performance evaluation of thermoplastic resin composition

Using the thermoplastic resin compositions prepared in Examples and Comparative Examples, physical properties were evaluated according to the following methods and are shown in Tables 1 and 2.

One) Tensile strength evaluation

After making the prepared test piece to a thickness of about 2 mm, a No. 4 test piece according to ASTM D638 was prepared and the tensile strength and elongation were measured according to ASTM D638. At this time, the number of test pieces used in the same test was 5.

2) hardness evaluation

Hardness was measured according to ASTM D-2240 with a TECLOCK A Durometer durometer on the surface of the test piece.

3) Scratch resistance evaluation

After producing a specimen with a width of 60 mm x length 60 mm x thickness of 3 mm, it was scratched with a scratcher at a distance of 100 mm under the condition of a load of 4.9 N and a speed of 100 mm/min, and then visually checked to evaluate grades 1 to 5.

Grade 1: Surface damage is conspicuous.

Grade 2: Damage to the surface is recognized.

Grade 3: Some damage to the surface is recognized, but it is not severe.

Grade 4: Slight damage to the surface is perceived.

Grade 5: Surface damage is not recognized.

4) Permanent compression set (%)

According to the ISO 815 method, a circular specimen having a diameter of 29 ± 0.5 mm x a thickness of 12.5 ± 0.5 mm was exposed at a temperature of 125 ° C for 70 hours, and then the difference in thickness before and after the test was measured to calculate the value.

5) Evaluation of embossability

The degree of emboss moldability was evaluated by checking the depth of embossing after application (molding) to an injection product, that is, after application to an injection product and injection.

◎: Excellent embossability

○ : Excellent embossability

△: Normal embossability

As shown in Tables 1 and 2 below, it was found that the mechanical properties of the examples were superior to those of the comparative examples.

In particular, in the case of the comparative example using the metal ion of 100 μm as the metal ion, the tensile strength and scratch resistance were lower than that of the examples, but had a high compression set, and the embossability was not good compared to the examples.

On the other hand, Examples 1 to 6 were all superior in scratch resistance compared to Comparative Example, and their tensile strength was also higher than that of Comparative Example. From the above experiments, it was confirmed that in the case of the examples, the mechanical properties were improved, and the hardness also had a reasonable level of hardness required for the prototype.

As described above, although the present invention has been described by limited embodiments, the present invention is not limited thereto, and is described below and the technical spirit of the present invention by those skilled in the art to which the present invention belongs. Of course, various modifications and variations are possible within the equivalent scope of the claims to be made.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 propylene resin 40 40 40 40 70 30 rubber composition 60 60 60 60 30 70 rubber composition EPDM 100 100 100 100 100 100 peroxide 0.1 0.1 0.1 0.1 0.1 0.1 acrylic acid 5 5 5 5 5 5 Li (nano) 5 5 5 Na (nano) 5 Mg (nano) 5 Zn (nano) 5 Tensile strength (Mpa) 10.2 10.0 9.8 9.7 15.2 8.5 Hardness (Shore) 72A 72A 72A 73A 80A 67A scratch resistant 5th grade 5th grade 5th grade 5th grade 4th grade 4th grade Compressive strain 10% 11% 13% 15% 55% 15% embossing ◎ ◎ ◎ ◎ ○ ◎

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 TPV 100 propylene resin 40 40 40 40 rubber composition 60 60 60 60 rubber composition EPDM 100 100 100 100 peroxide 0.1 0.1 0.1 0.1 acrylic acid 5 5 5 5 Li (micro) 5 Na (micro) 5 Mg (micro) 5 Zn (micro) 5 Tensile strength (Mpa) 8.0 8.9 8.6 8.3 8.9 Hardness (Shore) 80A 72A 72A 73A 72A scratch resistant 2nd grade level 3 level 3 level 3 level 3 Compressive strain 50% 19% 19% 21% 20% embossing ○ ○ ○ △ △

Claims (9)

(a) polypropylene resin; and
(b) A thermoplastic resin composition for automobile interior materials comprising a mixture of rubber compositions,
The rubber composition is a thermoplastic resin composition for automobile interior materials comprising an unsaturated rubber functionalized with a polar group and nano metal ions. According to claim 1,
(a) 30 to 70 parts by weight of a polypropylene resin; and
(b) a thermoplastic resin composition for automobile interior materials comprising 70 to 30 parts by weight of the rubber composition. According to claim 2,
(a) 40 parts by weight of polypropylene resin; and
(b) 60 parts by weight of the rubber composition, a thermoplastic resin composition for automotive interior materials. According to claim 1,
The rubber composition is based on 100 parts by weight of an unsaturated rubber functionalized with a polar group,
A thermoplastic resin composition for automobile interior materials prepared by mixing 1 to 30 parts by weight of nano metal ions. According to claim 1,
The unsaturated rubber is at least one selected from the group consisting of polyisoprene rubber, polybutadiene rubber, ethylene propylene diene EPDM rubber, styrene butadiene rubber and acrylonitrile butadiene rubber, a thermoplastic resin composition for automotive interior materials . According to claim 1,
The nano-metal is lithium, sodium, magnesium or zinc, the thermoplastic resin composition for automotive interior materials. According to claim 1,
The nano-metal has a particle size of 10 to 900 nm, a thermoplastic resin composition for automobile interior materials. According to claim 1,
The polar group is selected from the group consisting of acrylic acid, methacrylic acid, methyl acrylic acid, methyl methacrylic acid, ethyl acrylic acid, ethyl methacrylic acid, butyl acrylic acid and butyl methacrylic acid, a thermoplastic resin composition for automotive interior materials. According to claim 1,
The rubber composition further comprises at least one additive selected from an initiator, a crosslinking agent, an antioxidant, a lubricant, a catalyst and a UV stabilizer, a thermoplastic resin composition for automobile interior materials.