KR20140000554A - Polypropylene resin composition for high flexural modulus, high impact strength and low volatile organic compounds and manufactured by using the same - Google Patents

Abstract

Disclosed are: a polypropylene resin composition which contains 99-99.99 wt% of polypropylene resin, and 0.01-1 wt% of organic rigid nucleic agent for reducing bad odor from a molded product; and the molded product manufactured by using the same. The present invention provides: the polypropylene resin composition with remarkably reduced bad odor by having extremely small amount of VOC as well as strength and impact resistance by containing the optimum amount of specific rigid nucleic agent for the specific polypropylene resin; and the molded product manufactured by using the same.

Description

POLYPROPYLENE RESIN COMPOSITION FOR HIGH FLEXURAL MODULUS, HIGH IMPACT STRENGTH AND LOW VOLATILE ORGANIC COMPOUNDS AND MANUFACTURED BY USING THE SAME

The present invention relates to a polypropylene resin composition, and more particularly, to a polypropylene resin composition having excellent impact resistance, flexural modulus and low odor and a molded article produced using the same.

Generally, polypropylene resins are widely used for industrial purposes because they are easy to handle, recyclable, and have excellent mechanical, thermal, chemical and electrical properties. The use of such polypropylene resins are being actively applied to food containers. Recently, due to the light weight of moldings using polypropylene resins, interest in polypropylene resin compositions that can be used in food containers has emerged. . However, due to the decrease in thickness due to the light weight trend, such as food containers having a thickness of about 0.1 to 2 mm, problems of the strength and impact resistance of the moldings are accompanied, and a technique using a rigid nucleating agent in a polypropylene resin to reinforce the strength and impact resistance Although it has been known, there is a problem that it is difficult to apply to food-related moldings due to the odor of the rigid nucleating agent depending on the polypropylene resin composition.

Patent Publication No. 2002-55865 discloses a transparent polypropylene resin composition containing a sorbitol-based nucleating agent to improve transparency and prevent bleeding and odor, but uses a transparent nucleating agent and improves strength and impact resistance. No mention is made.

In addition, Korean Patent Publication No. 1038629 discloses a polypropylene resin composition containing a plate-shaped inorganic filler coated with calcium carbonate on the surface thereof to improve odor and surface damage resistance, but to improve both strength and impact resistance of the resin composition. It is not considered.

In addition, Korean Patent Publication No. 1132922 discloses a polyolefin composition in which odor and total volatile organic compounds are reduced by using calcium oxide, but a wide range of resins are applied, inorganic inorganic nucleating agents are used, and odor reduction effects are not satisfactory.

In addition, Patent Publication No. 0716575 discloses a resin having excellent transparency and impact resistance including a sorbitol-based, aluminum-based or sodium-based nucleating agent, but the specific physical properties of the resin composition according to the nucleating agent composition, and in particular, the use of the nucleating agent There is no mention of odor reduction.

In addition, Patent Publication No. 0791193 includes a granular complex additive containing a crystal nucleating agent of an alkali metal salt or hydroxyaluminum salt of an aromatic monocarboxylic acid or an alkali metal salt or hydroxyaluminum salt of an acidic aromatic phosphate ester compound. Although the polyolefin resin composition is disclosed, it does not mention the effect of reducing odor according to the use and content of the nucleating agent contained in the complex additive.

As such, when the polypropylene resin composition is applied to a food container having a thickness of about 0.1 to 2 mm, the disclosure of the polypropylene resin composition considering both the strength and impact resistance as well as the improvement in odor reduction is required. This is not presented.

Therefore, the present invention has been made to solve the above problems, using the same in the polypropylene resin composition to solve the problem of lowering the strength and impact resistance of the molded article when applied to a food container having a thickness of about 0.1 ~ 2mm as well as reducing odor It is intended to provide a polypropylene resin composition comprising a rigid nucleating agent excellent in effect and a molded article produced using the same.

In order to solve the above problems, the present invention provides a polypropylene resin composition containing 99 to 99.99% by weight of polypropylene resin and 0.01 to 1% by weight of an organic-based rigid nucleating agent for reducing the odor of moldings.

In addition, the polypropylene resin provides a polypropylene resin composition, characterized in that the propylene ethylene block copolymer having an ethylene content of 4 to 20% by weight.

In addition, the polypropylene resin provides a polypropylene resin composition, characterized in that the melt index is 0.1 ~ 5g / 10min (230 ℃, 2.16kg.f) and the molecular weight distribution is 3 ~ 20.

In addition, the organic-based rigid nucleating agent provides a polypropylene resin composition, characterized in that consisting of an organic phosphate ester salt.

In addition, the organic phosphate ester salt is sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate (sodium 2,2'-methylenebis- (4,6-di-tert-butylphenyl) phosphate) to provide a polypropylene resin composition.

In addition, the polypropylene resin composition is a polypropylene resin composition characterized in that the flexural modulus (ASTM D-790) is more than 12,000kgf / ㎠ and IZOD impact strength (ASTM D-256) is more than 60kgfcm / cm / cm To provide.

In addition, the polypropylene resin composition provides a polypropylene resin composition, characterized in that VOC (volatile organic compounds, measured by GMW15634 method) is less than 5.5ppm.

In order to solve the another problem, the present invention provides a molded product produced using the polypropylene resin composition.

According to the present invention, by selecting a specific rigid nucleating agent and containing it in the specific range of the polypropylene resin in the optimum range, the polypropylene resin composition and the odor is dramatically reduced by containing a very small amount of VOC as well as improving strength and impact resistance. Produced moldings can be provided.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Accordingly, it is to be understood that the constituent features of the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention, so that various equivalents and modifications It should be understood.

The present inventors reinforce the impact resistance and flexural modulus by containing a rigid nucleating agent when the polypropylene resin is applied to a product with an odor problem together with a problem of lowering strength and impact resistance, such as a food container having a thickness of about 0.1 to 2 mm. At the same time, by adopting a special rigid nucleating agent as the rigid nucleating agent, the polypropylene resin composition, particularly the propylene-ethylene block copolymer resin, is included in the optimum content to provide a polypropylene resin composition having excellent rigidity such as impact resistance, flexural modulus, and greatly reduced odor. It was found that the present invention can be achieved.

Accordingly, the present invention discloses a polypropylene resin composition comprising 99 to 99.99% by weight of polypropylene resin and 0.01 to 1% by weight of an organic-based rigid nucleating agent for reducing the odor of moldings. Here, the term 'composition' means a state before a specific product is specified through molding. For example, it may mean a material in the form of pellets or a mixture of compounding steps, and thus, even if the first molding process such as pellet form is completed, the embodiment of the present invention will be regarded as an aspect before completion into a specific final product form.

Hereinafter, each said component which comprises the polypropylene resin composition which concerns on this invention is demonstrated concretely.

(1) polypropylene resin

In the present invention, a polypropylene resin is used as a base resin applicable to the production of a molded article having a thickness of about 0.1 to 2 mm using a resin composition having various advantages. As the polypropylene resin, a polypropylene homopolymer, a copolymer containing propylene and at least one other olefin such as ethylene, butene, hexene, and the like may be used. In consideration of all of these, it is preferable to use a propylene-ethylene block copolymer, and more preferably, an ethylene content contained in the propylene-ethylene block copolymer is in the range of 4 to 20% by weight. When the ethylene content is less than 4% by weight, the rigidity of the resin composition may be improved, but the impact resistance may be lowered. When the ethylene content is higher than 20% by weight, the impact resistance may be improved, but deformation of the molding may occur when used at high temperatures. May be vulnerable.

The polypropylene resin preferably has a melt index of 0.1 to 5 g / 10 min (230 ° C., 2.16 kg · f) and a molecular weight distribution of 3 to 20. When the melt index is less than 0.1g / 10min, the strength of the manufactured molding may be more improved, but considering the process yield such as injection, extrusion, blow molding, etc., it is preferably at least 0.1g / 10min, and the purpose of the polypropylene resin composition In order to satisfy the flexural modulus, impact strength, and VOC content range, it is preferably less than 5 g / 10 min. In addition, it is necessary to select a polypropylene resin having an appropriate molecular weight distribution (MWD) in order to improve the moldability and product homogeneity when applied to the production of food containers having a thickness of about 0.1 ~ 2㎜, in the present invention It is preferable to select the polypropylene resin of 3-20, Preferably 3-8. Here, the molecular weight distribution (MWD) of the resin is a measure of the molecular weight range in the polymer, and the width of the molecular weight distribution is the ratio of the various molecular weight averages, for example, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Or Z-average molecular weight (Mz) to weight average molecular weight (Mw). The average molecular weight M may be calculated from Equation 1 below.

In Equation 1, Ni represents the number of molecules having a molecular weight Mi. When n is 0, M is number average molecular weight (Mn), when n is 1, M is weight average molecular weight (Mw), and when n is 2, M is Z-average molecular weight (Mz). The desired MWD function is the ratio of the corresponding M value (Mw / Mn or Mz / Mw). M and MWD can be measured by methods well known in the art.

(2) rigid nucleating agents

The polypropylene resin composition according to the present invention includes a nucleating agent, and includes an organic-based rigid nucleating agent for reducing the odor of a molded article together with improving the rigidity and impact resistance of the resin composition.

In general, nucleating agents are additives to accelerate the crystallization rate of the polymer, to refine the crystal size, to improve transparency, to shorten the process cycle time by increasing the crystallization rate, and to improve mechanical properties. The nucleating agent is classified into inorganic type nucleating agent such as talc, silica, kaolin, etc. and nucleating agent of organic type such as monomer or polymer, depending on the components thereof. It is divided into transparent nucleating agent and rigid nucleating agent for stiffness improvement.

At this time, the inventors of the present invention, when the organic phosphate ester salt is included in the propylene-ethylene block copolymer containing 4 to 20% by weight of ethylene in the polypropylene resin as an organic-based rigid nucleating agent for reducing the odor of the molding In addition to the improvement, the odor was dramatically reduced. Specifically, when the organic phosphate ester salt is added to the propylene-ethylene block copolymer as a rigid nucleating agent, an excellent stiffness of 12,000 kgf / cm 2 or higher and an IZOD impact strength of 60 kgf · cm / cm or more of the polypropylene resin composition And it can exhibit impact resistance, VOC (volatile organic compounds) is less than 5.5ppm can have a significantly improved low odor compared to the conventional polypropylene resin composition.

The organic-based rigid nucleating agent for reducing the odor of such a molded article is contained 0.01 to 1% by weight, preferably 0.02 to 0.1% by weight. Rigid nucleating agent used in the present invention exhibits a significantly improved effect on stiffness and impact resistance as well as odor reduction compared to other nucleating agents on the same content basis. However, the rigid nucleating agent is included in an amount of 0.01 to 1% by weight in consideration of the degree of stiffness improvement according to the addition of the rigid nucleating agent and the reduction in the odor of the desired bar and the efficiency compared to the addition amount.

As the organic-based rigid nucleating agent preferably used in the present invention, the organic phosphate ester salt is not particularly limited as long as it can exert the excellent effects as described above in terms of rigidity, impact resistance and low odor, but is most preferred organic phosphate ester. Sodium 2,2'-methylenebis- (4,6-di-tert-butylphenyl) phosphate may be used as the salt. . In addition, in order to balance the mechanical properties of the resin composition and other physical properties other than the low odor, one may consider using a nucleating agent mixture in which the organic phosphate ester salt is mixed with another inorganic-based nucleating agent or dispersing agent, but at least in terms of reducing odor. If considered, it is more preferable to use the organic phosphate ester salt alone than the mixture.

Meanwhile, the polypropylene resin composition according to the present invention may further include various functional additives according to the intention of the operator or the use of the final product in addition to the above components. Examples of functional additives include hydrolysis agents, flame retardants, antioxidants, colorants, lubricants, mold release agents, pigments, and the like, which may be used in small amounts alone or in combination of two or more.

Hereinafter, an Example and a comparative example are given and this invention is demonstrated in detail.

Example  One

Propylene-ethylene block copolymer (ethylene content 5-7 wt%, melt index 0.5g / 10min (ASTM D-1238, 230 ° C, 2.16 kg.f), molecular weight distribution 4-5 (ASTM D3536)) 99.95 wt% After mixing 0.05% by weight of sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate, the mixture was subjected to a monoaxial extruder (L / D = 25) having a diameter of 40 to 190 ° C. Reaction extruded, cooled and solidified in the temperature range to obtain a pellet-like composition. Thereafter, the obtained composition was molded in a temperature range of 190 to 250 ° C. with an injection molding machine to prepare a physical specimen.

Example  2

Example 1 except that 99.93% by weight of propylene-ethylene block copolymer and 0.03% by weight of sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate were mixed. In the same manner, a physical specimen was prepared.

Example  3

Example 1 except that 99.9% by weight of propylene-ethylene block copolymer and 0.1% by weight of sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate were mixed. In the same manner, a physical specimen was prepared.

Comparative Example  One

A physical specimen was prepared in the same manner as in Example 1, except that 100 wt% of the propylene-ethylene block copolymer was added in Example 1.

Comparative Example  2

Nuclear agent mixture (sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) instead of sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate in Example 1 A physical specimen was prepared in the same manner as in Example 1 except that 10% by weight of phosphate, 15% by weight of 1,2-cyclohexanedicarboxylic acid calcium salt, 80% by weight of talc and 5% by weight of dispersant were mixed. It was.

Comparative Example  3

Nuclear agent mixture (sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) instead of sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate in Example 2 A physical specimen was prepared in the same manner as in Example 2, except that 10% by weight of phosphate, 15% by weight of 1,2-cyclohexanedicarboxylic acid calcium salt, 80% by weight of talc, and 5% by weight of dispersant were mixed. It was.

Comparative Example  4

Nuclear agent mixture (sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) instead of sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate in Example 3 A physical specimen was prepared in the same manner as in Example 3 except that 10% by weight of phosphate, 15% by weight of 1,2-cyclohexanedicarboxylic acid calcium salt, 80% by weight of talc and 5% by weight of dispersant were mixed. It was.

Test Example

Flexural modulus, IZOD impact strength, GC-mass and VOC content were measured for the specimens prepared according to the Examples and Comparative Examples, and the results are shown in Table 1 below. In this case, the final judgment was marked as "excellent" when the flexural modulus of at least 11,000 kg · f / cm 2 for stiffness and the IZOD impact strength exceed 60 kg · f / cm 2 or more, otherwise as “normal”. When the VOC content is less than 6ppm "low", if more than 6ppm or less than 8ppm "normal", if more than 8ppm "high".

[How to measure]

(1) Flexural modulus: measured according to ASTM D-790.

(2) IZOD impact strength: measured according to ASTM D256.

(3) GC mass: The samples were heated at 200 ° C. for 20 minutes to detect volatile components.

(4) VOC (volatile organic compounds): measured by GMW15634 method.

Referring to Table 1 above, when the rigid nucleating agent according to the present invention is added (Examples 1 to 3) and not added (Comparative Example 1), the VOC content is relatively increased with the addition of the rigid nucleating agent. However, it is still showing excellent low odor within the rigid nucleating agent content range, and it can be seen that it is excellent in terms of rigidity.

On the other hand, compared with the case of adding a nucleating agent mixture in the same content as the rigid nucleating agent content according to the present invention (Comparative Examples 2 to 4), when using a nucleating agent consisting of only a specific rigid nucleating agent of the present invention as in the embodiment, both rigidity and odor It can be seen that it is excellent.

As such, when the existing nucleating agent material is used to improve the rigidity of the polypropylene resin composition, not only the degree of rigidity improvement is not satisfactory, but also its application may not be applicable to food-related packaging containers. When added to the propylene-ethylene block copolymer, it is possible to provide a polypropylene resin composition that satisfies the improved strength as well as the excellent impact resistance and low odor level required by the food-related molding market in recent years.

Claims (8)

A polypropylene resin composition comprising 99 to 99.99% by weight of polypropylene resin and 0.01 to 1% by weight of an organic-based rigid nucleating agent for reducing the odor of moldings. The method of claim 1,
The polypropylene resin is a polypropylene resin composition, characterized in that the propylene block copolymer having a ethylene content of 4 to 20% by weight. The method of claim 1,
The polypropylene resin is a polypropylene resin composition characterized in that the melt index is 0.1 ~ 5g / 10min (230 ℃, 2.16kg · f) and the molecular weight distribution is 3 ~ 20. The method of claim 1,
The organic-based rigid nucleating agent polypropylene resin composition, characterized in that consisting of an organic phosphate ester salt. 5. The method of claim 4,
The organic phosphate ester salt is sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate (sodium 2,2'-methylenebis- (4,6-di-tert-butylphenyl) phosphate) Polypropylene resin composition, characterized in that. The method of claim 1,
The polypropylene resin composition has a flexural modulus (ASTM D-790) of 12,000 kgf / cm 2 or more and an IZOD impact strength (ASTM D-256) of 60 kgf · cm / cm or more. The method of claim 1,
The polypropylene resin composition is a polypropylene resin composition characterized in that the VOC (volatile organic compounds, measured by GMW15634 method) is less than 5.5ppm. The molded article manufactured using the polypropylene resin composition of any one of Claims 1-7.