KR20110077382A - Block copolymer for heat sealable film applications and film manufactured therefrom - Google Patents

Abstract

PURPOSE: A block copolymer and a film manufactured therefrom are provided to ensure a low heat sealing temperature, transparency, and blocking resistance. CONSTITUTION: A block copolymer comprises 70-95 weight% of first copolymers and 5-30 weight% of second copolymers. The firsts copolymer are obtained by copolymerizing 78-99 weight% of propylene, 0.5-7 weight% of ethylene, and 0.5-15 weight% of 1-butene. The second copolymers are obtained by copolymerizing 40-90 weight% of propylene, 5-30 weight% of ethylene, and 5-30 weight% of 1-butene. The ratio of the intrinsic viscosity of the second copolymer to that of the first copolymer is 0.5-1.5.

Description

BLOCK COPOLYMER FOR HEAT SEALABLE FILM APPLICATIONS AND FILM MANUFACTURED THEREFROM}

The present invention relates to block copolymers and films made therefrom.

With the recent development of the distribution field, the demand for packaging films is steadily increasing. Packaging film is used by molding into a bag or sealing after packaging, and accordingly, properties such as Hot Tack and Heat Seal Property, Transparency, Anti-blocking Property, etc. Is required.

In particular, in order to shorten the time required for the heat sealing of the film, there is a method of sealing the film at a higher temperature or using a resin having a lower heat sealing temperature when manufacturing the film. Among them, the film is damaged by heat in the case of high temperature sealing. It is preferable to use a resin having a low heat-sealing temperature because there is a risk of it.

Previously, polypropylene homopolymers and polypropylene random copolymers were mainly used as heat sealing film materials. Recently, propylene, ethylene and 1- have excellent low temperature heat sealing properties and high heat sealing strength. Many studies have been made on butene terpolymers (hereinafter referred to as 'propylene-ethylene-1-butene terpolymers'). However, the propylene-ethylene-1-butene terpolymer is still not satisfactory at low temperature heat sealability and an improvement is required.

In general, the heat sealing temperature of the resin is related to the melting temperature of the resin, so that the lower the melting temperature, the lower the heat sealing temperature. From this point of view, in the propylene-ethylene-1-butene terpolymer, as the contents of ethylene and 1-butene increase, the heat seal temperature decreases with the melting temperature. However, when the content of ethylene and 1-butene is high, the stickiness of the terpolymer may be increased, causing process troubles. Also, there are a lot of low crystalline and low molecular weight materials, so when they are formed on the film, the transparency and the film are decreased. There is a problem that causes blocking.

Another way to improve the heat sealability of films is to blend polybutene-1 or linear polyethylene with low heat-sealing temperatures with propylene-ethylene-1-butene terpolymers. .

However, when the propylene-ethylene-1-butene terpolymer and the polybutene-1 are mixed, the low temperature heat sealability is improved, but the kneading property is poor, and thus there is a limit in fine dispersion, which results in a decrease in transparency. In comparison, when the propylene-ethylene-1-butene terpolymer and the linear polyethylene are mixed, the kneading property is excellent and the transparency is excellent. However, when the content of the linear polyethylene is 10% by weight or more, the compatibility of the polypropylene and the polyethylene is limited. There is a disadvantage of poor workability of the film. In addition, the above methods have a disadvantage in that the cost of the product increases because it is a method of mixing the two kinds of resins already produced.

The present invention provides a block copolymer having a low heat sealing temperature and excellent transparency and blocking resistance.

The present invention also provides a method for producing the block copolymer.

The present invention also provides a heat sealable film comprising the block copolymer.

The present invention,

A first copolymer copolymerized with 78 to 99 wt% propylene, 0.5 to 7 wt% ethylene, and 0.5 to 15 wt% 1-butene; And

Second copolymer copolymerized with 40 to 90% by weight propylene, 5 to 30% by weight ethylene, and 5 to 30% by weight 1-butene

It provides a block copolymer of.

The block copolymer comprises 70 to 95 wt% of the first copolymer; And block copolymerized with 5 to 30% by weight of the second copolymer.

In addition, the intrinsic viscosity ratio ([η] ₂ / [η] ₁ ) of the second copolymer to the intrinsic viscosity of the first copolymer is preferably 0.5 to 1.5.

In addition, the sum of the contents of ethylene and 1-butene included in the block copolymer is preferably 3.5 to 30% by weight.

On the other hand, the present invention provides a film comprising the block copolymer.

Hereinafter, a block copolymer and a film prepared therefrom according to specific embodiments of the present invention will be described.

The inventors of the present invention, in the course of studying the propylene, ethylene and 1-butene terpolymer (hereinafter referred to as 'propylene-ethylene-1-butene terpolymer') used as the main raw material of the heat-sealing film, propylene, When copolymerization of terpolymers in which ethylene and 1-butene are controlled differently to form a block has been found to be excellent in low-temperature heat sealing, but also excellent in anti-blocking property and transparency, thereby completing the present invention.

Such a block copolymer according to the present invention

A first copolymer copolymerized with 78 to 99 wt% propylene, 0.5 to 7 wt% ethylene, and 0.5 to 15 wt% 1-butene; And

Second copolymer copolymerized with 40 to 90% by weight propylene, 5 to 30% by weight ethylene, and 5 to 30% by weight 1-butene

Block copolymers.

That is, in the block copolymer according to the present invention, the first copolymer and the second copolymer form a block, and a method of preparing the block copolymer will be described later. First, the first copolymer constituting the block copolymer and The second copolymer will be described.

First copolymer

The first copolymer serves to impart proper rigidity and heat resistance while maintaining low temperature heat sealability and transparency of the final block copolymer.

The first copolymer is a random copolymer prepared from a composition comprising propylene, ethylene, and 1-butene, in order to express such properties, 78 to 99% by weight of propylene, 0.5 to 7% by weight of ethylene, and 1 It is preferred to copolymerize at 0.5-15% by weight of butene.

That is, the sum of the content of ethylene and 1-butene copolymerized to the first copolymer in order that the film prepared using the final block copolymer can express the minimum transparency and heat sealability required by the present invention It is preferable that it is 1 weight% or more. This is because when the content of ethylene and 1-butene is low, the crystallinity of the first copolymer is increased, and thus the transparency and heat sealability of the final block copolymer are lowered.

However, when ethylene and 1-butene are added more than necessary, the crystallinity of the first copolymer is rather deteriorated, so that the rigidity, heat resistance, and blocking resistance of the final block copolymer are Since it is inferior, it is preferable that the sum of ethylene and 1-butene content copolymerized with the said 1st copolymer is 22 weight% or less.

At this time, the content of ethylene and 1-butene copolymerized to the first copolymer is preferably 0.5 to 7% by weight and 0.5 to 15% by weight of 1-butene. Among them, the higher the content of ethylene, the higher the transparency and the heat-sealing property, but when added in excess, a large amount of low molecular weight material is generated during the polymerization process, the adhesiveness may be increased and accordingly the blocking resistance is deteriorated, in view of this content Can be adjusted within the range.

Second copolymer

The second copolymer serves to impart impact resistance and low temperature heat sealability to the final block copolymer, and to impart high transparency to the processed film.

The second copolymer is a random copolymer copolymerized with 40 to 90% by weight of propylene, 5 to 30% by weight of ethylene, and 5 to 30% by weight of 1-butene, and forms a block with the first copolymer, and a method of manufacturing the same. Will be described later.

That is, the second copolymer has a higher content of ethylene and 1-butene than the first copolymer, and thus has low crystallinity and high elasticity, thereby providing excellent impact resistance and low temperature heat sealability. In particular, the second copolymer is a polymerized monomer of the same kind as the first copolymer, and has excellent compatibility with the first copolymer, and fine dispersion is possible during processing of the final block copolymer, so that the transparency of the film is excellent. There is this.

In order to be able to express the above properties, the sum of the content of ethylene and 1-butene copolymerized to the second copolymer is preferably 10 to 60% by weight.

At this time, the content of ethylene and 1-butene copolymerized to the second copolymer is preferably 5 to 30% by weight and 5 to 30% by weight of 1-butene. Among them, the higher the content of ethylene, the higher the transparency and the heat-sealing property, but when added in excess, a large amount of low molecular weight material is generated during the polymerization process, the adhesiveness may be increased and accordingly the blocking resistance is deteriorated, in view of this content Can be adjusted within the range.

Block copolymer of the first copolymer and the second copolymer

In the block copolymer according to the present invention, the aforementioned first copolymer and the second copolymer form a block.

In this case, the block copolymer is preferably copolymerized with 70 to 95% by weight of the first copolymer, and 5 to 30% by weight of the second copolymer. That is, the content of the second copolymer is preferably 5% by weight or more, in order to express the minimum low-temperature heat sealing improvement effect, and in order to prevent the decrease in transparency and blocking resistance due to excessive addition The content of the copolymer is preferably 30% by weight or less.

The intrinsic viscosity ratio ([η] ₂ / [η] ₁ ) of the second copolymer to the intrinsic viscosity of the first copolymer is preferably 0.5 to 1.5, more preferably 0.8 to Can be 1.2. That is, the intrinsic viscosity is a physical property related to the compatibility and dispersibility of the first copolymer and the second copolymer, and the intrinsic viscosity ratio is preferably within the above range in order to prevent the transparency and blocking resistance of the film from decreasing.

In addition, the sum of the contents of ethylene and 1-butene copolymerized in the block copolymer is preferably 3.5 to 30% by weight. That is, in order to give a minimum low-temperature heat sealability improvement effect, the sum of the contents of ethylene and 1-butene in the entire block copolymer is preferably 3.5% by weight or more, and the rigidity, heat resistance, and blocking resistance decrease due to excessive addition. In order to prevent the addition, the sum of the contents of ethylene and 1-butene in the entire block copolymer is preferably 30% by weight or less.

On the other hand, the present invention provides a method for producing the block copolymer according to another embodiment.

Since the method for preparing the block copolymer may follow a conventional method in the art, the present invention is not particularly limited thereto.

However, preferably, a slurry polymerization step of polymerizing a monomer using n-hexane, n-heptane, or the like, which is a hydrocarbon solvent, as a reaction medium; A bulk polymerization process using propylene as a monomer as a liquid reaction medium; And a gas phase polymerization process in which the monomers in the gas phase form a fluidized bed to polymerize.

More preferably, the following method using a continuous process of bulk polymerization and gas phase polymerization can be followed.

That is, the method for producing a block copolymer according to the present invention

Forming a first copolymer in which 78 to 99% by weight of propylene, 0.5 to 7% by weight of ethylene, and 0.5 to 15% by weight of 1-butene are copolymerized in the bulk polymerization reaction;

Forming a second copolymer in which 40 to 90% by weight of propylene, 5 to 30% by weight of ethylene, and 5 to 30% by weight of 1-butene are copolymerized by the gas phase polymerization reaction; And

Block copolymerizing the first copolymer and the second copolymer

It may include.

At this time, the forming step and the block copolymerization step of the second copolymer may be performed at the same time.

The production method according to the present invention is not only excellent in productivity because the polymerization rate is faster than the polymerization process using only the gas phase process, but also easier to control the composition of monomers in the first copolymer and the second copolymer than the polymerization process using only the bulk process. Thus, there is an advantage that can be produced a block copolymer with improved low-temperature heat sealability, transparency, heat resistance and blocking resistance required by the present invention.

Hereinafter, the steps that may be included in the manufacturing method will be described in detail.

Formation of First Copolymer (Bulk Polymerization)

In the method for preparing the block copolymer according to the present invention, first, propylene, ethylene, and 1-butene may be reacted by bulk polymerization to form a first copolymer.

The step is preferably carried out in two or more continuous bulk reactors, more preferably in two consecutive bulk reactors. In this case, when using two consecutive bulk reactors it is possible to control the physical properties of the final product by the same or different operating conditions of each reactor.

The bulk reactor may be continuously supplied with propylene, ethylene, 1-butene, a catalyst system, and hydrogen as a raw material for polymerization, in which hydrogen is added to control the molecular weight of the copolymer.

In the bulk polymerization process, a propylene-ethylene copolymer, a propylene-1-butene copolymer, a propylene-ethylene-1-butene terpolymer, etc. may be generated initially, and finally, a propylene-ethylene-1-butene terpolymer Is generated.

At this time, the supply amount of each component may be determined in consideration of the composition (78 to 99% by weight of propylene, 0.5 to 7% by weight of ethylene, and 0.5 to 15% by weight of 1-butene) of the first copolymer which is the final product of the bulk polymerization step. have.

The catalyst system introduced into the forming step of the first copolymer may be used in the art to which the present invention pertains, and is not particularly limited thereto. Preferably, the catalyst system includes a Ziegler-Natta catalyst. Can be used.

The catalyst system may include a Ziegler-Natta solid catalyst, an organoaluminum compound, and an electron donating compound. In consideration of the reaction efficiency, it is preferable to use a high active solid catalyst having a polymerization amount of 20 kg or more per 1 g of the catalyst. In addition, a catalyst system having a high stereoregularity having a pentad isotactic index (Pentad Isotactic Index) of 92% by weight or more, measured by Nuclear Magnetic Resonance in the production of homopolypropylene using the catalyst system, is more preferable. .

It is preferable to use a trialkyl aluminum compound as the organoaluminum compound in the catalyst system, and more preferably trimethyl aluminum, triethyl aluminum, and tripropyl aluminum. , Tributyl aluminum, and the like can be used.

In addition, as the electron donating compound of the catalyst system, it is preferable to use an alkoxysilane-based compound, more preferably cyclohexylmethyldimethoxysilane, dicyclopentyldimethoxysilane, diisopentyldimethoxysilane Diisopropyldimethoxysilane and the like can be used.

On the other hand, the step of forming the first copolymer is preferably carried out at a temperature of 50 to 80 ℃. That is, it is preferable that a bulk polymerization temperature is 50 degreeC or more so that the minimum polymerization reaction rate can be obtained. In addition, when the temperature is increased more than necessary, the solubility of ethylene and hydrogen in the reactants is reduced, making it difficult to control the composition of the copolymer, and the cohesiveness of the copolymer increases, which causes process trouble. In order to prevent this, the bulk polymerization temperature is 80 ° C. It is preferable that it is the following.

In addition, the step of forming the first copolymer may be carried out under a pressure of 20 kgf / ㎠ or more, preferably 20 to 50 kgf / ㎠. That is, the bulk polymerization pressure is preferably 20 kgf / cm 2 or more in order to improve the solubility of the reactants to improve the production efficiency.

In addition, in the forming of the first copolymer, the average residence time in the reactor is preferably 0.5 to 2 hours in consideration of the physical properties of the first copolymer and the polymerization reaction efficiency.

Formation of the second copolymer (gas polymerization), and block copolymerization

Subsequently, the method for preparing a block copolymer according to the present invention comprises the steps of reacting propylene, ethylene, and 1-butene by gas phase polymerization to form a second copolymer; And block copolymerizing the first copolymer and the second copolymer.

At this time, the forming step of the second copolymer and the step of block copolymerization may be carried out iii) separately or ii) simultaneously.

That is, the manufacturing method according to the present invention can be proceeded to i) a method of preparing the first copolymer and the second copolymer, respectively, and kneading the two copolymers in a separate apparatus, or ii) the above-described steps. The first copolymer prepared in the above was transferred to a gas phase reactor, and in the presence of the first copolymer, propylene, ethylene, and 1-butene were added to copolymerize the second copolymer so as to form a block with the first copolymer. It can be done with

Among the above methods, ii) a method of simultaneously performing the forming step and the block copolymerization step of the second copolymer is more advantageous in terms of production efficiency and physical properties of the final block copolymer.

Since the method of proceeding the two steps separately can be easily performed by those skilled in the art with reference to the simultaneous progression method described below, the following will be described.

In the forming step and the block copolymerization step of the second copolymer, propylene, ethylene, 1-butene, and hydrogen may be continuously supplied to the gas phase reactor in the presence of the first copolymer, and the amount of each component is supplied to the second air. It may be determined in consideration of the composition (40 to 90% by weight of propylene, 5 to 30% by weight of ethylene, and 5 to 30% by weight of 1-butene) and physical properties.

In particular, the content of the reactants additionally added to the gas phase reactor is preferably added so that the molar ratio of [ethylene / (ethylene + propylene + 1-butene)] is 0.1 to 0.5 and the molar ratio of (hydrogen / ethylene) is 0.01 to 0.1. Do.

In addition, the forming step and the block copolymerization step of the second copolymer is preferably carried out at a temperature of 60 to 90 ℃, pressure 10 to 30 kgf / ㎠. That is, the gas phase polymerization conditions may be determined within the above range in consideration of the polymerization reaction efficiency and the flowability of the reactants.

In addition, the forming step and the block copolymerization step of the second copolymer is preferably an average residence time in the reactor is 0.5 to 2 hours in consideration of the physical properties of the final product and the polymerization reaction efficiency.

Through the above-described method, it is possible to manufacture a block copolymer of the first copolymer and the second copolymer. More details will be described through examples.

However, each of the above steps is not only an embodiment of the method for producing a block copolymer according to the present invention, but may further include a step that is commonly performed in the art before or after each step, The steps alone do not limit the method of preparing the block copolymer of the present invention.

On the other hand, the present invention provides a film comprising the block copolymer according to another embodiment.

The film according to the present invention has the advantage of having a low heat sealing temperature, transparency, and excellent blocking resistance as the block copolymer is included.

That is, the film has a heat sealing temperature of 110 to 116 ° C., which enables heat sealing even at a lower temperature than previous heat sealing films. At this time, the heat-sealing temperature is stored for 24 hours in a constant temperature and humidity chamber of the film 23 ± 1 ℃, humidity 50 ± 5%, and then press the two film specimens by using a heat gradient tester (Heat Gradient Tester) After the surface is bonded with five metal bars with inclined temperature at kgf / cm 2, 2 seconds, a temperature of 700 g or more is applied with a tensile tester.

In addition, the film has a low haze of 1.5 to 3.0% based on ASTM D-1003, which is excellent in transparency, and has a blocking value of 50 to 200 g / 10 cm 2, which is easy to handle the film. . Here, the blocking value is a value obtained by measuring the maximum stress (Max Stress) by a tensile tester after storing the two film specimens for 24 hours under a load of 40 ℃, 50 g / 10 ㎠ overlapping the two film specimens, the larger the measured value This is easy to stick to each other means that handling is inconvenient.

The composition for preparing the film may include, in addition to the block copolymer according to the present invention, a component commonly used in forming a film, but is not limited thereto, and preferably, an antiblocking agent, an antioxidant, a lubricant and a nucleating agent. It may include.

In addition, the manufacturing method of the film is not particularly limited because it can be carried out by a conventional method in the art, preferably T-die method, blown film extrusion method (Blown) film extrusion method).

As the block copolymer according to the present invention is a block of two kinds of polymers, each of which has controlled properties, the film produced therefrom is not only capable of heat sealing at low temperatures, but also has excellent transparency and blocking resistance as a film. The required physical properties are excellent.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments are described to facilitate understanding of the present invention. However, the following examples are intended to illustrate the present invention without limiting it thereto.

In the following Examples and Comparative Examples, the polymerization amount of propylene (P), ethylene (E) and 1-butene (1-B) in the copolymer, and the physical properties of the block copolymer were measured in the following manners, respectively. Are shown in Tables 1 and 2 below.

1) Content of ethylene and 1-butene in the copolymer (% by weight): measured by spectroscopic method using FT-IR.

2) Melt Index (g / 10min): Measured under the conditions of temperature 230 ° C. and load 2.16 kg based on ASTM D 1238.

3) Intrinsic viscosity (dl / g): measured in 135 ° C Decalin solvent.

4) Melting point (Tm) and crystallization temperature (Tc): Measured using a differential scanning calorimetry (DSC).

[ Example ]

The overall polymerization process used a system consisting of a prepolymerization reactor, two loop bulk reactors, one gas phase reactor, two flash drums, a dryer and a product storage facility. At this time, the volume of the loop-type bulk reactor was 140 liters, the volume of the gas phase reactor was 220 liters, the volume of the flash drum was used each 70 liters.

Example  One

(Bulk polymerization stage)

Two bulk reactors were used. Ziegler-Natta solid catalyst, triethylaluminum and cyclohexylmethyldimethoxysilane were first fed to the first bulk reactor via prepolymerization with propylene and hydrogen. At this time, the first bulk reactor was further fed with propylene, ethylene, 1-butene and hydrogen to proceed with the polymerization reaction. The composition in the first bulk reactor was continuously transferred to the second bulk reactor, and the second bulk reactor was further fed with propylene, ethylene, 1-butene and hydrogen to proceed with the polymerization reaction. Specific operating conditions are as follows.

The first bulk reactor was fed at a rate of 55.0 kg / hr of liquid propylene, 0.61 kg / hr of gaseous ethylene, and 4.0 kg / hr of liquid 1-butene, while being 0.4 g / hr of solid catalyst (2.6% by weight of titanium as active ingredient). , 8.5 g / hr of triethylaluminum and 1.77 g / hr of cyclohexylmethyldimethoxysilane were continuously fed.

The second bulk reactor was fed at a rate of 35.0 kg / hr propylene, 0.41 kg / hr ethylene and 3.0 kg / hr 1-butene.

The two bulk reactors were maintained at a temperature of 60.0 ° C. and a pressure of 35.0 kgf / cm 2, respectively, and hydrogen was supplied to the two reactors to maintain a hydrogen concentration of 1000 ppm in order to control the molecular weight. The sum of the average residence times of the two reactors was about It was 1.6 hours.

The first copolymer prepared through the above process was fed to the first flash drum to separate the unreacted gas component, and was continuously transferred to the gas phase reactor.

(Phase polymerization stage)

In the gas phase reactor, in the presence of the first copolymer, additionally propylene, ethylene, 1-butene and hydrogen are fed to polymerize the second copolymer, and the polymerized slurry copolymer is passed through a second flash drum and a dryer. The unreacted gas was separated to prepare a block copolymer in which the first copolymer and the second copolymer were finally blocked.

At this time, the gas phase reactor was operated under a temperature of 75 ° C. and a pressure of 14 kgf / cm 2, propylene, ethylene, 1-butene and hydrogen introduced into the gas phase reactor were introduced into the gas phase, propylene was 5.0 kg / hr, and 1-butene was 10.0. At a rate of kg / hr, ethylene was supplied so that the molar ratio of [ethylene / (ethylene + propylene + 1-butene)] was 0.15, and hydrogen was supplied so that the molar ratio of (hydrogen / ethylene) was 0.03.

The residence time of the gas phase reactor was about 0.7 hours, and the average reaction amount at the time of completion of the polymerization was (60,000 g copolymer) / (g catalyst).

(Manufacture of Film)

0.05 wt% of calcium stearate and 0.15 wt% of phenolic antioxidants are mixed with the final block copolymer powder prepared through the above process, and granulated in a single extruder having a diameter of 40 mm. It was prepared in the form of pellet (Pellet), which was molded by the T-die method (T-die method).

Example  2

In Example 1 (Bulk polymerization step), except that the amount of ethylene introduced into the first bulk reactor was changed to 0.2 kg / hr and the amount of ethylene introduced into the second bulk reactor was changed to 0.75 kg / hr. A block copolymer was prepared in the same manner as in Example 1, and a film was molded using the block copolymer.

Example  3

The feed amount of the reactant introduced into the gas phase reactor in Example 1 (gas phase polymerization step) was 3 kg / hr of propylene, 15 kg / hr of 1-butene, molar ratio of [ethylene / (ethylene + propylene + 1-butene)] 0.25, A block copolymer was prepared in the same manner as in Example 1, except that the molar ratio of (hydrogen / ethylene) was changed to 0.035, and a film was molded using the block copolymer.

Example  4

The amount of reactants fed into the gas phase reactor in Example 3 (gas phase polymerization step) was changed to a molar ratio of 0.4 [ethylene / (ethylene + propylene + 1-butene)] and a molar ratio of (hydrogen / ethylene) of 0.042. Except that, a block copolymer was prepared in the same manner as in Example 3, and the film was molded using the block copolymer.

Example  5

Except that in Example 1 (bulk polymerization stage), the amount of ethylene introduced into the first bulk reactor was changed to 0.55 kg / hr and the amount of ethylene introduced into the second bulk reactor was changed to 0.37 kg / hr. A block copolymer was prepared in the same manner as in Example 1, and a film was molded using the block copolymer.

Example  6

In Example 1 (Bulk polymerization step), except that the amount of ethylene introduced into the first bulk reactor was changed to 0.18 kg / hr and the amount of ethylene introduced into the second bulk reactor was changed to 0.71 kg / hr. A block copolymer was prepared in the same manner as in Example 1, and a film was molded using the block copolymer.

Example  7

The feed amount of the reactant introduced into the gas phase reactor in Example 5 (gas phase polymerization step) was 3 kg / hr propylene, 15 kg / hr 1-butene, molar ratio 0.37 of [ethylene / (ethylene + propylene + 1-butene)], A block copolymer was prepared in the same manner as in Example 5, except that the molar ratio of (hydrogen / ethylene) was changed to 0.04, and a film was molded using the block copolymer.

[ Comparative example ]

Comparative example  One

Only the (bulk polymerization step) of Example 1 was carried out to prepare a first copolymer, and the film was molded using the first copolymer.

At this time, after the first copolymer was produced, it was not fed to the gas phase reactor, but was fed to the second flash drum, followed by drying.

Comparative example  2

A first copolymer was prepared in the same manner as in Example 1, except that 1-butene was not supplied in (Bulk polymerization step) of Example 1, and the film was molded using the first copolymer.

Comparative example  3

1-butene was not supplied to the gas phase reactor in Example 1 (gas phase polymerization stage), and the remaining amount of reactant was supplied in an amount of 8 kg / hr propylene, a molar ratio of [ethylene / (ethylene + propylene)] 0.25, (hydrogen / ethylene) A block copolymer was prepared in the same manner as in Example 1, except that the molar ratio of 0.035 was changed to 0.035.

At this time, it was found that 1-butene was somewhat polymerized in the second copolymer while unreacted 1-butene was transferred to the continuous (phase polymerization stage) in (bulk polymerization stage) (see Table 1).

Comparative example  4

The amount of reactant introduced into the gas phase reactor in Example 1 (gas phase polymerization step) was changed to a molar ratio of 0.4 [ethylene / (ethylene + propylene + 1-butene)] and a molar ratio of (hydrogen / ethylene) of 0.02. Except that, a block copolymer was prepared in the same manner as in Example 1, and the film was molded using the block copolymer.

Comparative example  5

Only the (bulk polymerization step) of Example 5 was carried out to prepare a first copolymer, and the film was molded using the first copolymer.

At this time, after the first copolymer was produced, it was fed to the second flash drum without being transferred to the gas phase reactor, and this was carried out in the order of drying.

Comparative example  6

A block copolymer was prepared in the same manner as in Example 5, except that 1-butene was not supplied in (Bulk polymerization step) of Example 5, and the film was molded using the block copolymer.

Comparative example  7

In the gas phase reactor of Example 5, 1-butene was not supplied to the gas phase reactor, and the remaining amount of reactant was supplied in an amount of 8 kg / hr propylene, a molar ratio of [ethylene / (ethylene + propylene)] 0.29, (hydrogen / ethylene) A block copolymer was prepared in the same manner as in Example 5, except that the molar ratio of 0.035 was changed so as to form a film using the block copolymer.

content
(weight%) First copolymer Second copolymer Block copolymer P E 1-B P E 1-B First
Copolymer 2nd
Copolymer E 1-B
room
city
Yes One 93.2 2.8 4.0 81.7 9.2 9.1 93 7 3.2 4.4 2 93.2 2.7 4.1 81.6 9.5 8.9 93 7 3.2 4.4 3 93.1 2.8 4.1 70.7 15.1 14.2 90 10 4.0 5.1 4 93.1 2.8 4.1 65.3 22.1 12.6 87 13 5.3 5.2 5 93.0 2.5 4.5 79.7 10.2 10.1 91 9 3.2 5.0 6 92.8 2.2 5.0 79.5 11.1 10.6 91 9 3.0 5.5 7 92.5 2.7 4.8 67.7 18.1 14.2 87 13 4.7 6.0
ratio
School
Yes One 93.2 2.8 4.0 - - - 100 - 2.8 4.0 2 95.5 4.5 - - - - 100 - 4.5 - 3 93.1 2.7 4.2 77.6 20.7 1.7 88 12 4.9 3.9 4 92.8 2.8 4.2 69.1 16.6 14.3 67 33 3.9 4.5 5 93.0 2.5 4.5 - - - 100 - 2.5 4.5 6 95.5 4.5 - 67.0 18.9 14.1 89 11 6.1 1.6 7 92.7 2.7 4.6 64.5 35.5 - 88 12 6.6 4.0

block
Copolymer
Properties Intrinsic viscosity Melt Index
(g / 10 min) Melting point
(℃) crystallization
Temperature
(℃) Primary copolymer
([η] ₁ ) Secondary copolymer
([η] ₂ ) [η] ₂ / [η] ₁
room
city
Yes One 1.54 1.77 1.15 7.2 134 93 2 1.53 1.56 1.02 7.4 134 93 3 1.52 1.32 0.87 7.5 133 92 4 1.55 1.81 1.17 7.0 133 92 5 1.51 1.51 1.00 7.8 133 92 6 1.51 1.34 0.89 7.9 133 92 7 1.55 1.77 1.14 7.0 132 91
ratio
School
Yes One 1.54 - - 7.2 134 93 2 1.55 - - 6.8 135 94 3 1.53 1.45 0.95 7.4 134 93 4 1.54 2.08 1.35 7.2 133 92 5 1.51 - - 7.8 133 92 6 1.52 1.60 1.05 7.7 135 94 7 1.50 1.47 0.98 8.0 132 91

[ Experimental Example ]

The heat seal temperature, haze, and blocking values of the films prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 3 below.

1) Heat sealing temperature (℃): After keeping the film in a constant temperature and humidity room with a temperature of 23 ± 1 ℃ and a humidity of 50 ± 5% for 24 hours, press the two film specimens using a heat gradient tester. After the surface was bonded with five metal bars with a temperature inclined at 2 kgf / cm 2 and 2 seconds, a tensile tester showed a temperature of more than 700 g.

2) Haze (%): The haze was measured according to ASTM D 1003.

3) Blocking value (g / 10 cm 2): Two film specimens were overlapped and stored under a load of 40 ° C. and 50 g / 10 cm 2 for 24 hours, and then a maximum stress was measured by a tensile tester. In this case, the larger the measured value, the lower the blocking resistance (Anti-blocking Property), the film sticks to each other, which means that the handling of the film is inconvenient.

Film properties Heat Seal Temperature (℃) Haze (%) Blocking value (g / 10㎠)
room
city
Yes One 116 2.1 100 2 115 2.0 100 3 114 1.9 130 4 112 2.6 180 5 115 2.1 120 6 114 2.0 90 7 113 2.3 170
ratio
School
Yes One 119 2.0 60 2 118 4.1 70 3 115 3.3 320 4 114 8.4 160 5 120 2.0 60 6 118 4.3 140 7 115 3.6 400

As can be seen through Table 1 to Table 3, Comparative Examples 1, 2 and 5 to prepare a film using only the first copolymer component, Comparative Examples 3, 6 and 7 is preferably 1-butene content In Comparative Example 4, the content of the first copolymer and the second copolymer was outside the preferred range, and thus the heat sealing temperature was higher than that of the Example, and the haze value and the blocking value were high. The physical properties as appeared to be poor.

In contrast, Examples 1 to 7 have a low haze value and a low blocking value while the heat sealing temperature is lower than that of the comparative example as the composition of the first copolymer and the second copolymer and the content in the block copolymer correspond to the preferred ranges. The quality of the film was found to be excellent.

Claims (5)

A first copolymer copolymerized with 78 to 99 wt% propylene, 0.5 to 7 wt% ethylene, and 0.5 to 15 wt% 1-butene; And Second copolymer copolymerized with 40 to 90% by weight propylene, 5 to 30% by weight ethylene, and 5 to 30% by weight 1-butene Block copolymers. The method of claim 1, 70 to 95 wt% of the first copolymer; And 5 to 30% by weight of the second copolymer In-block copolymer. The block copolymer of claim 1, wherein an intrinsic viscosity ratio of the second copolymer to an intrinsic viscosity of the first copolymer is 0.5 to 1.5. The block copolymer according to claim 1, wherein the sum of the contents of ethylene and 1-butene in the block copolymer is 3.5 to 30% by weight. Film comprising the block copolymer according to any one of claims 1 to 4.