KR20160064391A - PP based natural fiber complex pellet, extrusion composition comprising the pellet, and molded product - Google Patents

Abstract

The present invention relates to polypropylene-based natural fiber composite material pellets, extruded compositions comprising pellets, and molded articles. According to the present invention, polypropylene-based natural fiber composite material pellets containing a specific grade of polypropylene, It is possible to provide an environmentally friendly polypropylene-based natural fiber composite material pellet, an extrusion composition including pellets, and a molded article, which are in conformity with the processability and extrusion and dispersibility required for automotive interior materials by providing the composition.

Description

TECHNICAL FIELD [0001] The present invention relates to a polypropylene natural fiber composite material pellet, an extrusion composition including the pellet, and a molded product,

The present invention relates to a polypropylene natural fiber composite material pellet, an extrusion composition comprising the pellet, and a molded article, and more particularly, to a natural fiber composite material pellet comprising a specific grade of polypropylene, Friendly natural polypropylene based natural fiber composite material pellets, an extruded composition including pellets, and a molded product, which are in conformity with processability and extrusion and dispersibility required for use in automobile interior materials.

As an eco-friendly natural fiber composite material, polypropylene-based natural fiber composite materials have been attempted.

As a conventional application example, Korean Patent Laid-Open Publication No. 2010-0107855 discloses a technique of blending impact grade polypropylene, natural fiber (kenaf), maleic anhydride compatibilizer and ethylene-octene copolymer rubber and extrusion processing.

However, in this case, the extrusion process alone has a disadvantage in that the dispersibility is not good, the natural fiber content to be added is limited, and it is difficult to stably realize high physical properties due to such a dispersion problem.

Accordingly, Korean Patent Publication No. 2010-0054660 discloses polypropylene, natural fiber (Jute base), stearic acid, organosilicic additive, ultraviolet ray inhibitor , A porous inorganic filler, and calcium carbonate are mixed and extruded.

However, there is a limit to heat resistance at the time of reversal, and it is difficult to expect improvement in impact and physical properties.

In order to overcome such disadvantages, development of environmentally friendly polypropylene-natural fiber composite materials is urgently required as an automotive interior material.

In order to solve the problems of the prior art as described above, the present invention relates to an environmentally friendly polypropylene-natural fiber composite material for use in automobile interior materials, and a PP-based natural fiber composite material pellet including a specific grade of polypropylene, It is an object of the present invention to provide an environmentally friendly polypropylene-based natural fiber composite material pellet, an extrusion composition including pellets, and a molded article, which are in conformity with processability and extrusion and dispersibility required for automotive interior materials by providing an extruded composition.

In order to accomplish the above object, the present invention provides a polypropylene resin composition comprising a polypropylene resin and natural fibers,

Wherein the polypropylene resin comprises a polypropylene resin having a crystallization degree of 50 to 60% in an amount of 0 to 50% by weight, and b) 50 to 100% by weight of a polypropylene resin having a degree of crystallization of 70% , ≪ / RTI >

A polypropylene-based natural fiber composite material pellet is provided.

The present invention also provides an extrusion composition comprising a polypropylene-based natural fiber composite material pellet, wherein the polypropylene-based natural fiber composite material pellet is composed of a polypropylene resin and natural fibers,

Wherein the polypropylene resin comprises a polypropylene resin having a crystallization degree of 50 to 60% in an amount of 0 to 50% by weight, and b) 50 to 100% by weight of a polypropylene resin having a degree of crystallization of 70% , Which is obtained by a kneading step, a single extrusion step, and a pelletizer step.

Further, the present invention provides a molded article obtained by molding the extrusion composition described above.

According to the present invention, by providing a polypropylene-based natural fiber composite material pellet including a specific grade of polypropylene and an extrusion composition containing the same, an eco-friendly polypropylene type natural fiber composite material satisfying the processability and extrusion- An extrusion composition comprising pellets, pellets, and a molded article.

1 is a SEM photograph (magnification: 45 times) of the extruded specimen of Example 2 according to the present invention.
2 is a SEM photograph (magnification: 45 times) of a specimen obtained by biaxial extrusion without preparing the pellet of Comparative Example 2. Fig.
3 is a photograph of the extruded strand of the extruded specimen of Fig.
4 is a photograph of the extruded strand of the extruded specimen of Fig.

Hereinafter, the present invention will be described in detail.

The polypropylene type natural fiber composite material pellet of the present invention is composed of a polypropylene resin and a natural fiber, wherein the polypropylene resin has a polypropylene resin content of 100 wt% or less and a) a polypropylene resin having a crystallinity of 50 to 60% To 50% by weight, and b) a polypropylene resin having a crystallinity of at least 70% by weight.

The polypropylene resin having a crystallinity of 50 to 60%, for example, has a mass average molecular weight of 174,000 g / mol or more, or 174,000 to 200,000 g / mol, and has a crystallization temperature (Tc) of 109 to 117 캜, (230 占 폚, 2.16 kg load) measured in accordance with ASTM D1238 of 20 to 30 g / 10 min (Tm) at 160 to 165 占 폚, or 162 to 164 占 폚 Lt; RTI ID = 0.0 > ethylene-propylene < / RTI > block copolymer.

The term "crystallinity" refers to a value measured by the C ₁₃ NMR method, unless otherwise specified. The polypropylene resin preferably has an isotactic index (II) of 97% or more as a high crystallinity characteristic when measured by C ₁₃ NMR analysis. Within this range, the polypropylene resin has excellent heat resistance, impact resistance and scratch resistance . The C < ₁₃ > According to the method disclosed by A. Zambelii et al. (Macro molecules 6 925 (1973)), meso pentad fraction of polypropylene is measured by a signal of methyl group measured by C ₁₃ NMR spectrum. The meso pentad fraction is a fraction of propylene monomer units in a molecular chain in which five propylene monomer units are meso-bonded continuously. When the meso pentad fraction is high, crystallinity and mechanical properties are improved.

The term "crystallization temperature (Tc)" refers to a value measured by a dynamic scanning calorimeter (DSC) method unless otherwise specified.

The term "melting temperature (Tm) " refers to a value measured by a dynamic scanning calorimeter (DSC) method unless otherwise specified.

(B) a polypropylene resin having a crystallization degree of 70% or more, for example, having a mass average molecular weight of 195,000 g / mol or more, or 195,000 to 230,000 g / mol and having a crystallization temperature Tc of 120 to 140 ° C , A melt index (230 DEG C, 2.16 kg load) measured according to ASTM D1238 of 165 to 175 DEG C or 167 to 171 DEG C is 5 to 15 g / 10 min Isotactic ethylene-propylene block copolymer. As the b) polypropylene resin, a highly crystalline homopolymer type may also be used in combination.

The polypropylene resin may be contained in an amount of 50 to 70% by weight or 45 to 65% by weight based on 100% by weight of the total amount of the polypropylene resin and the natural fiber, and within this range, And the effect of extrusion processability can be provided.

Examples of the natural fibers include those obtained by chemically modifying at least one selected from jute, hemp, flax, kenaf, bamboo, wood flour, and the like .

The chemical modification is not particularly limited as long as it can remove hemicellulose, lignin, and a little wax contained in the fiber. For example, alkali treatment can be mentioned.

The natural fibers are effectively used for improving the dispersibility, extrudability, and physical properties when they are cut into a size of about 1 cm and used.

The pellet may be one obtained by, for example, a kneading process, a single extrusion process, and a pelletizer process.

The kneading step may be performed by using various mixing devices such as a kneader, a mixer, a super mixer, a roll mill, or a Banbury mixer.

The kneading step may be carried out using a kneader as a specific example.

The extrusion composition according to the present invention comprises a polypropylene-based natural fiber composite material pellet, wherein the polypropylene-based natural fiber composite material pellet is composed of a polypropylene resin and a natural fiber, and the polypropylene resin has a polypropylene resin content From 0 to 50% by weight of a polypropylene resin having a crystallinity of from 50 to 60% and b) from 50 to 100% by weight of a polypropylene resin having a crystallinity of at least 70% , And a pelletizer process.

The extrusion composition can provide an excellent effect for improving dispersibility and extrusion processability (see FIG. 1).

For example, the extruded composition may contain 1-10 parts by weight, 1-8 parts by weight, or 1-5 parts by weight of a maleic anhydride compatibilizer based on 100 parts by weight of the total amount of the pellets and the compounds constituting the extrusion composition In this range, it is possible to provide a coupling function between the polypropylene resin and the natural fiber.

The maleic anhydride-based compatibilizer may be, for example, polypropylene grafted with 0.1 to 8 wt%, 0.1 to 1 wt%, or 0.3 to 0.6 wt% of maleic anhydride.

The extrusion composition may include, for example, an ethylenic impact modifier within the range of 5 to 15 parts by weight, or 6 to 12 parts by weight based on 100 parts by weight of the total of the pellets and the compounds constituting the extrusion composition, The strength improvement effect can be provided.

Examples of the ethylene-based impact modifier include an ethylene-octene copolymer having an octene content of 30% by weight or less and a melt index (190 ° C, 2.16 kg) of 1-10 g / 10 min or 1-7 g / 10 min.

For example, the extruded composition may contain phosphate based nucleating agent in an amount of 5 parts by weight or less based on 100 parts by weight of the total amount of the pellets and the compounds constituting the extrusion composition, and the degree of crystallization is increased within this range, have.

Examples of the phosphate nucleating agent include sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate, sodium 2,2'-ethylidenebis (4,6- (4,6-tert-butylphenyl) -2-ethylhexylphosphate, and sodium 2,2'-methylenebis (4,6-tert- butylphenyl) ≪ / RTI > and octadecyl phosphate.

The extrusion composition may include, for example, at least one selected from an oxidative stabilizer and a lubricant in an amount of 3 parts by weight or less based on 100 parts by weight of the total of the pellets and the compounds constituting the extrusion composition. The oxidation stabilizer and the lubricant are not particularly limited as long as they are of a kind usually used in the polyolefin field.

The extruded composition may contain additives such as a light stabilizer, a chain extender, a catalyst, a release agent, a pigment, a dye, an antistatic agent, an antibacterial agent, a processing aid, a metal deactivator, a fuming inhibitor, an inorganic filler, And at least one additive selected from the group consisting of lignans. The additive may be used within a range that does not adversely affect the physical properties of the extruded composition of the present invention.

The extruded composition of the present invention is optionally mixed with the additive in a mixer or a super mixer and then melt-kneaded in a temperature range of 180 to 200 ° C using a twin-screw extruder to obtain pellets to obtain an extruded product can do. Further, the pellets may be sufficiently dried by using a dehumidifying dryer or a hot-air dryer, and then injection-processed to produce an injection-molded article.

The molded article according to the present invention is obtained by molding the above extruded composition.

The molded product may be, for example, an automobile interior material, an electric / electronic product case, an architectural interior material, or the like.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention, but the present invention is not limited thereto.

[Example]

Examples 1 to 4, Comparative Examples 1 to 3

<Production of polypropylene-based natural fiber composite material pellets>

The contents of the polypropylene resin and the natural fiber in the ingredients shown in the following Table 1 were added to the kneader in the stated amounts, kneaded, and then extruded through a single extruder to obtain pellets from the pelletizer.

For reference, in Comparative Example 2, pellets were not produced from a polypropylene resin and a natural fiber, and the pellets were extruded after being kneaded and kneaded together with the other components (d) to (g) .

The polypropylene resin and natural fiber related materials used here are as follows:

(a) a general grade polypropylene (PP) having a mass average molecular weight (Mw) of 174,000 g / mol or more, a crystallinity of 50 to 60%, a crystallization temperature (Tc) of 109-117 캜 and a melting temperature (Tm) Polypropylene having a weight (g) measured at a temperature of 230 占 폚 under a load of 2.16 kg for 10 minutes in accordance with D1238 of 15 g / 10 min.

* (b) High-grade polypropylene (PP): A copolymer having a mass average molecular weight (Mw) of at least 195,000 g / mol, a crystallinity of at least 70%, a crystallization temperature (Tc) of 125 ° C and a melting temperature (Tm) of 169 ° C and according to ASTM D 1238 , A weight (g) measured at a temperature of 230 DEG C for 10 minutes under a load of 2.16 kg of 10 g / 10 min.

* (c) Natural fiber: Twisted jute pellets of 1 cm inside and outside length treated with alkali were applied.

(d) Maleic anhydride-based compatibilizer: Polypropylene grafted with maleic anhydride, and the maleic anhydride is contained in 0.5% by weight of the compound.

(e) Ethylene-based impact modifier: It is used as an ethylene-octene rubber containing not more than 30% by weight of octene and having a weight measured at 190 DEG C under a load of 2.16 kg for 10 minutes in accordance with ASTM D1238 of 5 g / 10 min .

(f) Phosphate nucleating agent: sodium 2,2'-methylenebis- (4,6-di-tert-butylphenyl) phosphate (purity more than 99 wt%

Category (% by weight) Example Comparative Example One 2 3 4 One 2 3 (a) General grade polypropylene (PP) - - 28 - 57 57 52 (b) High crystalline grade
Polypropylene (PP) 62 57 29 52 - - 5 (c) Natural fiber 20 25 25 25 25 25 25 (d) Maleic anhydride compatibilizer 5 5 5 5 5 5 5 (e) Ethylene-based impact modifier 10 10 10 10 10 10 10 (f) Phosphate nucleating agent <5 (g) Oxidation stabilizer + lubricant <3 <3 <3 <3 <3 <3 <3

<Extruded Compositions and Molded Articles>

The components (a), (b) and (c) of Table 1 above were used to prepare the pellets prepared in the manner previously described (Comparative Example 2, The ingredients shown in Table 1 were added to a super mixer in the amounts shown in Table 1 and mixed well and then the mixture was extruded through a twin-screw extruder extruder) to obtain pellets after melt-kneading at a temperature range of 200 to 290 ° C. This pellet was used as a specimen for physical property test.

The physical properties test method is as follows, and the results are summarized in Table 2 below.

<Test method>

Tensile Strength (MPa): Measured under ASTM D 638 cross head speed 50 mm / min.

Flexural modulus (MPa): Measured at 10 mm / min by ASTM D 790 method.

* Heat distortion temperature (℃): Measured based on ASTM D 648 degradation (4.6 kg / cm 2).

* Impact strength (J / m): Measured on 1/8 inch basis by ASTM D 256 method.

* Processability: The extracted extruded strands were judged to have three stages of excellent (⊚), normal (◯) and defective (X) based on the transferability to the pelletizer.

* Dispersibility: Based on the SEM results, it was judged in three stages of excellent (⊚), normal (◯), and poor (X).

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 With or without composite pellets U U U U U radish U Tensile Strength (MPa) 30 32 27 33 25 19 25 Flexural modulus (MPa) 1870 1990 1790 2100 1600 1300 1630 Heat deformation temperature (캜) 135 137 132 141 120 110 123 Impact strength (J / m) 80 7 70 6 40 35 49 Processability ◎ ○ ○ ○ ○ X ○ Dispersibility ◎ ○ ○ ○ ○ X ○

As shown in Table 2, in the extrusion molded articles of Examples 1 to 4, in which the polypropylene type resin and the natural fiber composite material pellets were produced according to the present invention and the resin of the high crystalline grade was contained in the polypropylene type resin in an appropriate amount, Strength, flexural modulus, heat distortion temperature, impact strength, workability, and dispersibility were all improved.

On the other hand, in the extrusion-molded article of Comparative Example 1 in which the polypropylene-based resin and the natural fiber composite material pellets were produced but the high-crystalline grade resin in the polypropylene-based resin was not included, the tensile strength, It was confirmed that the elastic modulus and the heat distortion temperature were somewhat reduced and the impact strength was remarkably reduced.

In the extrusion molded article of Comparative Example 2 in which the polypropylene type resin and the natural fiber composite material pellets were not produced, the tensile strength, flexural modulus, heat distortion temperature, impact strength, workability and dispersibility of the extrusion molded articles of Examples 1 to 4 It can be confirmed that all of them are remarkably reduced.

Further, in the extrusion-molded article of Comparative Example 3, in which the polypropylene-based resin and the natural fiber composite material pellets were produced in the polypropylene-based resin and the degree of resin of the high crystalline grade was less than the proper range, And the mechanical properties were remarkably reduced.

SEM photographs (magnification: 45 times) of the specimens of Example 2 and Comparative Example 2 were also shown in Figs. 1 and 2 with respect to dispersibility, and each of these extruded strands was shown in Figs. 3 and 4.

As a result, FIG. 1 shows that the natural fibers are uniformly dispersed in the polypropylene resin as compared with FIG. 2, and when the appearance of the strands of FIGS. 3 and 4 is compared, It was confirmed that the extrudability and dispersion were poor in comparison with the reinforcing materials of Example 2. [

<Additional Experimental Examples 1 and 2>

As a further experimental example 1, the same process as in Example 1 was repeated except that (b) the high crystalline grade PP in Example 1 was replaced with 50 wt%, which is less than the appropriate range.

The resultant specimens were tested for physical properties in the same manner as in Example 1, and found to have a tensile strength of 38 MPa, a flexural modulus of 2100 MPa, a heat distortion temperature of 142 DEG C, an impact strength of 40 J / ) And the dispersibility was X (defective), and the results of the extrudability of the extrusion molded articles in Examples 1 to 4 were very poor compared to the extrusion molded articles.

As a further experimental example 2, the same process as in Example 1 was repeated, except that (b) the high crystalline grade PP in Example 1 was replaced with 70 wt%, which is more than the proper range.

The resultant specimens were tested for physical properties in the same manner as in Example 1. As a result, tensile strength was 25 MPa, flexural modulus was 1,200 MPa, heat distortion temperature was 110 DEG C, impact strength was 105 J / ) And the dispersibility was ⊚ (excellent), which was not improved in the properties of the conventional polypropylene as compared with the extrusion molded articles of Examples 1 to 4, and had no effect of reinforcing natural fibers.

Claims (15)

Polypropylene resin and natural fiber,
Wherein the polypropylene resin comprises a polypropylene resin having a crystallization degree of 50 to 60% in an amount of 0 to 50% by weight, and b) 50 to 100% by weight of a polypropylene resin having a degree of crystallization of 70% , &Lt; / RTI &gt;
Polypropylene based natural fiber composite pellets. The method according to claim 1,
Wherein the polypropylene resin is in the range of 50 to 70% by weight based on 100% by weight of the total of the polypropylene resin and the natural fiber
Polypropylene based natural fiber composite pellets. The method according to claim 1,
Wherein the natural fiber is characterized in that at least one selected from the group consisting of Jute, Hemp, Flax, Kenaf, Bamboo, and Wood flour is chemically modified
Polypropylene based natural fiber composite pellets. The method according to claim 1,
Characterized in that the pellets are obtained by a kneading step, a single extrusion step, and a pelletizing step
Polypropylene based natural fiber composite pellets. Wherein the polypropylene-based natural fiber composite material pellets comprise a polypropylene-based natural fiber composite material pellet, wherein the polypropylene-based natural fiber composite material pellet comprises a polypropylene resin and natural fibers,
Wherein the polypropylene resin comprises a polypropylene resin having a crystallization degree of 50 to 60% in an amount of 0 to 50% by weight, and b) 50 to 100% by weight of a polypropylene resin having a degree of crystallization of 70% Characterized by being obtained by a kneading step, a single extrusion step, and a pelletizing step
Extrusion composition. 6. The method of claim 5,
Wherein the extruded composition contains maleic anhydride-based compatibilizer in an amount of 1 to 10 parts by weight based on 100 parts by weight of the total of the pellets and the compounds constituting the extrusion composition
Extrusion composition. The method according to claim 6,
Wherein the maleic anhydride-based compatibilizer is polypropylene grafted with 0.1 to 1% by weight of maleic anhydride
Extrusion composition. 6. The method of claim 5,
Characterized in that the extruded composition comprises an ethylenic impact modifier within a range of 5 to 15 parts by weight based on 100 parts by weight of the total of the pellets and the compounds constituting the extrusion composition
Extrusion composition. 9. The method of claim 8,
The ethylene-based impact modifier is an ethylene-octene copolymer having an octene content of 30% by weight or less and has a melt index (190 DEG C, 2.16 kg) of 1-10 g / 10 min
Extrusion composition. 6. The method of claim 5,
Wherein the extruded composition comprises 5 parts by weight or less based on 100 parts by weight of the total of the pellets and the compounds constituting the extrusion composition
Extrusion composition. 11. The method of claim 10,
The phosphate nucleating agent is selected from sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate, sodium 2,2'-ethylidenebis (4,6- Phosphate, sodium 2,2'-methylenebis (4,6-tert-butylphenyl) -2-ethylhexyl phosphate, and sodium 2,2'-methylenebis (4,6-tert- butylphenyl) -octadecyl phosphate And at least one selected from the group consisting of
Extrusion composition. 6. The method of claim 5,
Wherein the extruded composition contains at least one selected from an oxidizer and an activator in an amount of not more than 3 parts by weight based on 100 parts by weight of the total of the pellets and the compounds constituting the extruded composition
Extrusion composition. 6. The method of claim 5,
Characterized in that the extruded composition is applied to a twin-screw extruder
Extrusion composition. A molded article obtained by molding the extruded composition of claim 5 or claim 13. 15. The method of claim 14,
Wherein the molded article is an automobile interior material, an electric / electronic product case, or a building interior material
Shaped article.

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