KR20140001627A - Polypropylene resin composition for superior pelletizing stability and potential high melt index - Google Patents

Abstract

Disclosed is a polypropylene resin composition comprising a polypropylene resin and a molecular mass regulator which can form a composition in the shape of a pellet at an extrusion temperature of 190-230°C, and is enabled to have a potentially high melt flow index according to the adjustment of a processing temperature by using a pellet-shaped composition as it is, and making the polypropylene resin composition have a melt index higher than the pellet-shaped composition in an environment with a temperature higher than the extrusion temperature. The present invention can provide a polypropylene resin composition, a pellet composition manufactured using the same and a product manufactured using the pellet composition, wherein the polypropylene resin composition is made to have a high melt flow index using temperature adjustment without an additional special process during the process of using the polypropylene resin pellet-shaped composition as it is during the meltblown product molding after making the polypropylene composition does it have superior pelletizing stability and a potentially higher melt flow index because the polypropylene resin composition can be made into the shape of a pellet having a proper melt index at the usual extrusion temperature.

Description

POLYPROPYLENE RESIN COMPOSITION FOR SUPERIOR PELLETIZING STABILITY AND POTENTIAL HIGH MELT INDEX}

The present invention relates to a polypropylene resin composition, and more particularly to a polypropylene resin composition having excellent granulation stability and potential high melt flow.

In general, polypropylene resins are easy to handle, recyclable, and excellent in mechanical, thermal, chemical, and electrical properties, and are widely used for industrial purposes. In recent years, polypropylene resins have been used as raw materials for manufacturing long fiber nonwoven fabrics. Long fiber nonwovens typically consist of a spunbond nonwoven, a meltblown nonwoven or a combination thereof. In general, the fiber diameter of the spunbond nonwoven fabric is 20 µm, and a raw material having a melt index of 20 to 60 g / 10 min (230 ° C., 2.16 kgf) of polypropylene resin is used. In this case, the diameter of the fiber is significantly lowered to 2 μm, so that a raw material having a high melt flowability having a melt index of 100-2000 g / 10 min (230 ° C., 2.16 kgf) is used. In the case of the nonwoven fabric manufactured using the nonwoven fabric, it is possible to form a finer fiber than the nonwoven fabric by the span bond method, thereby improving the feel of the nonwoven fabric.

Nonwoven fabrics manufactured by the spanbond method, the melt blown method, or a combination thereof are widely used in various fields, such as sanitary, agricultural, household, industrial, and medical, for example, diapers for infants Since the softness of the nonwoven fabric is important because the same nonwoven fabric for hygiene is in contact with human skin, the melt blown molding method is widely used.

On the other hand, in the production of a polypropylene resin composition having a high melt flow rate of about 100 ~ 2000g / 10min to provide as a raw material used for the melt blown method in a petrochemical plant, the high melt flowability of the resin during extrusion Due to the decrease in melt tension of the polymer, the cutting stability of the pellets in the extruder is lowered, making it difficult to obtain pellets of uniform size, and there is a danger of shutting down the factory because the cutting of the resin is not smooth. In addition, when a large amount of pellets of non-uniform size are present in the polypropylene resin composition, hopper clogging of the extruder may occur during molding during the nonwoven fabric processing, and thus molding may be impossible.

In order to solve the problems occurring in the production of a polypropylene resin composition having a high melt flow in the petrochemical plant, cutting the pellet by lowering the extruder temperature to the melting point of the polypropylene resin to ensure the cutting stability of the extruder Techniques for producing products in the form of powder or granules without securing pellets or extruding polymerized polypropylene are known.However, to ensure cutting stability, the extruder is produced by lowering the extruder temperature. In this case, the production load of the polypropylene should be lowered, and the cutting stability of the polypropylene product produced thereafter will be affected, thereby limiting the process efficiency.

Patent Publication No. 2009-119007 uses an organic peroxide series as a molecular weight regulator in preparing a polypropylene for producing a melt-blown nonwoven fabric having a high melt flow property. Processing at a temperature lower than the temperature, there is a problem in the process efficiency as described above, and also in the case of organic peroxide, polypropylene contains a large amount of volatile components, there is a problem that can cause discoloration of the fiber at a high temperature.

In addition, Korean Patent Publication No. 10986986 discloses fluidity of polypropylene resin in a fiber spinning process by using a hindered hydroxylamine ester system as a molecular weight regulator of polypropylene in the production of a nonwoven fabric having a multi-layer structure including a meltblown layer. It is proposed as a means for controlling, but the fluidity control method is complicated and does not mention the utilization in the petrochemical plant as a matter of the post-production of the polypropylene resin composition on the pellet.

Accordingly, the present invention has been made to solve the above problems, to produce a pellet-like polypropylene resin composition in a petrochemical plant that can be used in a process requiring high melt flow of the polypropylene resin composition, such as melt blown product molding In general, pelletizing polypropylene resin composition prepared in a petrochemical plant during subsequent processing, such as melt blown product molding, has excellent granulation stability by extrusion molding without changing the extruder temperature of polypropylene used in a petrochemical plant. The present invention is to provide a polypropylene resin composition that can be used as it is to implement high melt flow.

In addition, the present invention provides a pellet composition prepared using the polypropylene resin composition and a product manufactured using the same.

In order to solve the above problems, the present invention is a polypropylene resin composition comprising a polypropylene resin and a molecular weight modifier, it is possible to form a pellet composition at an extrusion temperature of 190 ~ 230 ℃, using the pellet composition as it is and the extrusion By providing a higher melt index relative to the composition on the pellet in subsequent processing at a temperature higher than temperature, it provides a polypropylene resin composition capable of having potentially high melt flowability under processing temperature control.

In addition, the polypropylene resin is a propylene homopolymer or a copolymer of propylene and at least one olefin selected from the group consisting of ethylene, butene, pentene, hexene and octene provides a polypropylene resin composition.

In addition, the molecular weight regulator provides a polypropylene resin composition comprising a hindered hydroxylamine ester (hindered hydroxylamine ester) structure represented by the following formula (1).

[Formula 1]

R 1 is a resonance of a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a 3 to 10 membered cyclic alkyl group having 3 to 30 carbon atoms, or a 3 to 10 membered ring having 3 to 30 carbon atoms It is a cyclic alkyl group having a structure, R2 and R3 are each a linear alkyl group having 1 to 20 carbon atoms or a branched alkyl group having 3 to 20 carbon atoms, or R2 and R3 are cyclically linked together with N to 3 to 30 carbon atoms Phosphorus is composed of 4 to 10 membered cyclic rings, or 5 to 10 membered rings having 4 to 30 carbon atoms.

In addition, the molecular weight regulator is a polypropylene resin composition, characterized in that 0.01 to 4 parts by weight based on 100 parts by weight of the polypropylene resin.

In addition, the pellet-like composition provides a polypropylene resin composition, characterized in that the melt index is 20 ~ 100g / 10min (230 ℃, 2.16kgf).

In addition, the pellet-like composition provides a polypropylene resin composition, characterized in that the molecular weight distribution (Mw / Mn) is 5 or less.

In addition, the high temperature environment is a processing temperature environment of 250 ~ 300 ℃, polypropylene resin, characterized in that the melt index is higher than the composition of the pellet phase in the subsequent processing is 100 ~ 2000g / 10min (230 ℃, 2.16kgf) To provide a composition.

In addition, the subsequent processing provides a polypropylene resin composition, characterized in that the nonwoven fabric processing by the meltblown method.

The present invention for solving the other problems, provides a pellet composition produced using the polypropylene resin composition.

The present invention for solving the another problem, provides a product produced using the pellet composition.

According to the present invention, it can be produced in a pellet phase having a proper melt index at a normal extrusion temperature to have excellent granulation stability and potentially high melt flow, so that the pellet phase in subsequent processing such as melt blown product molding By using the polypropylene resin composition as it is, using a polypropylene resin composition that can satisfy the high melt flow of the polypropylene resin composition through temperature control without a special additional process, and the pellet composition and pellet composition prepared using the same Products 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 invention is a polypropylene resin composition comprising a polypropylene resin and a molecular weight modifier, which is capable of forming a composition of pellets at an extrusion temperature of 190 to 230 ° C, but using the composition of the pellets as it is and subsequent processing in a higher temperature environment than the extrusion temperature. The present invention discloses a polypropylene resin composition capable of exhibiting a high melt index relative to the composition on the pellet, thereby potentially having high melt flowability according to processing temperature control.

In the present invention, polypropylene resin is selected as the base resin capable of potentially having high melt flowability according to processing temperature control. The polypropylene resin is not particularly limited. For example, a propylene homopolymer, a copolymer of propylene with one or more olefins selected from the group consisting of ethylene, butene, pentene, hexene and octene, and the like, may be used to form a high melt flow in subsequent processing with the resin composition to be produced. You can have sex.

In the present invention, the molecular weight modifier is added and extruded to the polypropylene resin to produce a pellet-like composition, at the extrusion granulation temperature of the conventional polypropylene resin 190 ~ 230 ℃ to have a relatively low melt index of the polypropylene resin composition In order to ensure granulation stability, in the subsequent processing in a relatively high temperature environment using the pellet-like composition, the melt index is higher than that of the pellet-like composition. 0.01 to 4 parts by weight, preferably 0.1 to 2 parts by weight. When the content of the molecular weight regulator is less than 0.01 parts by weight, the degree of improvement of the melt index may not be satisfactory in subsequent processing in a high temperature environment, and when it exceeds 4 parts by weight, it may be difficult to secure cutting stability during granulation.

The molecular weight modifier is added to the polypropylene resin in an appropriate amount and the pelletized composition extruded at a normal extrusion temperature of 190 ~ 230 ℃ exhibits a melt index of 20 ~ 100g / 10min to ensure cutting stability of the pellets to solve the problem of granulation stability Will be solved.

Such a molecular weight regulator has a melt flowability according to the extrusion molding as described above, to have a high melt flowability in subsequent processing in a high temperature environment described below, and is not particularly limited, if not organic peroxide series, but is represented by the formula It may comprise a hindered hydroxylamine ester (hindered hydroxylamine ester) structure, the hindered hydroxylamine ester structure is included 20 mol% or more, preferably 50 mol% or more, more preferably 80 mol% or more Can be.

[Formula 1]

R 1 is a resonance of a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a 3 to 10 membered cyclic alkyl group having 3 to 30 carbon atoms, or a 3 to 10 membered ring having 3 to 30 carbon atoms It is a cyclic alkyl group having a structure, R2 and R3 are each a linear alkyl group having 1 to 20 carbon atoms or a branched alkyl group having 3 to 20 carbon atoms, or R2 and R3 are cyclically linked together with N to 3 to 30 carbon atoms Phosphorus is composed of 4 to 10 membered cyclic rings, or 5 to 10 membered rings having 4 to 30 carbon atoms.

The pelletized composition extruded by adding the molecular weight modifier shows a melt index of 20 to 100 g / 10 min to ensure cutting stability of the pellet and at the same time the molecular weight distribution (MWD; Mw / Mn) is 5 or less, preferably 3.5 or less. By having a narrow molecular weight distribution, it is possible to increase the process efficiency in the subsequent processing in high temperature environment, such as fiber spinning. That is, in general, it is known that the narrower the molecular weight distribution in the subsequent processing in a high temperature environment such as fiber spinning, such as fiber spinning, the easier the stretching and the less the occurrence of single yarns in the stretching process, the molecular weight regulator according to the present invention. Pellet-like compositions prepared by using the PSA can potentially raise the melt index, and the pelletized composition can be used in subsequent processing to induce decomposition of polymer chains, thereby narrowing the molecular weight distribution to significantly reduce the occurrence of single yarn fibers. Will be.

In addition, in the case of forming the fiber using the resin composition, it undergoes uniaxial stretching, and thus has similar stretching characteristics during stretching by narrow molecular weight distribution, thereby exhibiting excellent moldability and uniform physical properties in the fiber manufacturing process. Therefore, the polypropylene fiber produced using the polypropylene resin composition having a narrow molecular weight distribution of the present invention becomes more advantageous for spinning in spinning molding and improves the homogeneity of the final product.

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.

The pellet-like polypropylene resin composition according to the present invention can be produced through a known extrusion process. For example, the step of polymerizing a polypropylene resin having a melt index of about 0.1 ~ 100g / 10min in a polymerization reactor and drying the solution used as a monomer or a solvent to obtain a polypropylene resin powder; Reacting and extruding the hindered hydroxylamine ester molecular weight modifier and the dried polypropylene resin powder at an extruder temperature of 190 to 230 ° C; And cutting the reaction-extruded polypropylene resin composition in pellet form by a cutting blade in an extruder; or mixing in a silo so that the cut pellets have overall uniform properties before subsequent processing. Packaging with a propylene resin product; may be prepared further.

In the present invention, the pellet-like polypropylene resin composition has a melt index of 100 to 100 ° C without a special addition material for improving the melt index in a relatively high temperature environment, specifically, a temperature environment of 250 to 300 ° C, than a granulation temperature of 190 to 230 ° C. It is dramatically improved to 2000 g / 10 min, preferably 500 to 2000 g / 10 min, more preferably 1000 to 2000 g / 10 min, and is very convenient for processing processes requiring high melt flow such as fiber spinning using a polypropylene resin composition. Can be used. The subsequent processing step in which the high melt flowability is required is not particularly limited as long as it is a region in which the pellet-like polypropylene resin composition according to the present invention can be used as a raw material, and may be, for example, a nonwoven fabric processing step by a melt blown method. have.

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, a comparative example, and a test example are given and this invention is demonstrated in detail.

Example  One

100 parts by weight of polypropylene (melt index 0.5 g / 10 min (ASTM D-1238, 230 ° C., 2.16 kgf)) and 0.01 part by weight of a molecular weight modifier containing a hindered hydroxylamine ester structure represented by the following formula (2) The mixture was then extruded at a temperature of 220 ° C. with a monoaxial extruder (L / D = 25) having a diameter of 40 mm, cooled and solidified, and then cut with a rotary knife to prepare a pellet-like composition.

(2)

Example  2

A pellet-like composition was prepared in the same manner as in Example 1 except that 1 part by weight of the molecular weight modifier was mixed.

Example  3

A pellet-like composition was prepared in the same manner as in Example 1, except that 1.2 parts by weight of the molecular weight modifier was mixed in Example 1.

Example  4

A pellet-like composition was prepared in the same manner as in Example 1 except that 1.5 parts by weight of the molecular weight modifier was mixed.

Example  5

A pellet-like composition was prepared in the same manner as in Example 1 except that 1.7 parts by weight of the molecular weight modifier was mixed.

Example  6

A pellet-like composition was prepared in the same manner as in Example 1, except that 2.0 parts by weight of the molecular weight modifier was mixed in Example 1.

Comparative Example  One

A pellet-like composition was prepared in the same manner as in Example 3 except that the extrusion temperature was adjusted to 240 ° C. in Example 3.

Comparative Example  2

A pellet-like composition was prepared in the same manner as in Example 3, except that the extrusion temperature was adjusted to 260 ° C. in Example 3.

Comparative Example  3

A pelletized composition was prepared in the same manner as in Example 3, except that the extrusion temperature was adjusted to 280 ° C. in Example 3.

The components, contents and extrusion conditions according to the examples and the comparative examples are summarized in Table 1 below.

Test Example  One

The melt index and the molecular weight distribution of the pellet-like compositions prepared according to the Examples and Comparative Examples were measured according to the following method, and the results are shown in Table 2 below.

[How to measure]

(1) Melt index: Measured by ASTM D-1238 at 230 캜 and 2.16 kgf.

(2) Molecular weight distribution (Mw / Mn): measured by ASTM D3536 method.

Referring to Table 2, in the case where a proper amount of hindered hydroxylamine ester is added to the polypropylene resin as a molecular weight modifier, under temperature conditions exceeding the general extrusion temperature range of 190 ~ 230 ℃ (see Comparative Example 3) Although the melt index of the pellet composition is more than 100g / 10min, it is undesirably shown. However, in the case of extrusion within a general extrusion temperature range (Examples 1 to 6), the melt index is 25.5 to 99g / 10min, indicating excellent granulation stability. Able to know. At this time, it can be seen that the melt index of the pellet composition increases in proportion to the hindered hydroxylamine ester content. In addition, even in the case of the molecular weight distribution of the pellet composition, all are 3.5 or less, it can be confirmed that it has very advantageous physical properties in the subsequent processing in a high temperature environment such as fiber spinning.

Test Example  2

Using a pellet-like composition prepared according to Examples 2 and 3 by fiber spinning at a temperature of 290 ℃ by melt blown to prepare a nonwoven molding, the melt index and molecular weight in the same manner as in Test Example 1 for the nonwoven molding The distribution was measured and the results are shown in Table 3 below.

Referring to Table 3, it can be seen that the melt index is significantly increased by about 20 times when processing in a relatively high temperature environment than the granulation temperature for the polypropylene resin composition. That is, the pellet-like polypropylene resin composition according to the present invention has potentially high melt flow while ensuring granulation stability, and can be used as it is under temperature control in a subsequent processing step where such high melt flow is required. It can be seen that a significant effect in terms of efficiency or productivity can be exhibited.

Claims (10)

A polypropylene resin composition comprising a polypropylene resin and a molecular weight modifier, wherein a pellet-like composition can be formed at an extrusion temperature of 190 to 230 ° C., but the pellet-like composition is used as it is and the pellet is used in subsequent processing at a higher temperature than the extrusion temperature. A polypropylene resin composition capable of exhibiting a high melt index relative to the composition of the phase, potentially having a high melt flowability under process temperature control. The method of claim 1,
The polypropylene resin is a propylene homopolymer or a copolymer of propylene with at least one olefin selected from the group consisting of ethylene, butene, pentene, hexene and octene. The method of claim 1,
The molecular weight regulator is a polypropylene resin composition comprising a hindered hydroxylamine ester (hindered hydroxylamine ester) structure represented by the formula (1).
[Chemical Formula 1]

R 1 is a resonance of a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a 3 to 10 membered cyclic alkyl group having 3 to 30 carbon atoms, or a 3 to 10 membered ring having 3 to 30 carbon atoms It is a cyclic alkyl group having a structure, R2 and R3 are each a linear alkyl group having 1 to 20 carbon atoms or a branched alkyl group having 3 to 20 carbon atoms, or R2 and R3 are cyclically linked together with N to 3 to 30 carbon atoms Phosphorus is composed of 4 to 10 membered cyclic rings, or 5 to 10 membered rings having 4 to 30 carbon atoms. The method of claim 1,
The molecular weight regulator is a polypropylene resin composition, characterized in that 0.01 to 4 parts by weight based on 100 parts by weight of the polypropylene resin. The method of claim 1,
The pellet composition is a polypropylene resin composition, characterized in that the melt index is 20 ~ 100g / 10min (230 ℃, 2.16kgf). The method of claim 1,
The pellet-like composition has a molecular weight distribution (Mw / Mn) of 5 or less polypropylene resin composition. The method of claim 1,
The high temperature environment is a processing temperature environment of 250 ~ 300 ℃, polypropylene resin composition characterized in that the melt index is higher than the composition of the pellet phase in the subsequent processing is 100 ~ 2000g / 10min (230 ℃, 2.16kgf). The method of claim 7, wherein
The subsequent processing is a polypropylene resin composition, characterized in that the nonwoven fabric processing by the meltblown method. The pellet composition manufactured using the polypropylene resin composition of any one of Claims 1-8. A product prepared using the pellet composition of claim 9.