KR20000066740A - Propylene-ethylene-butene-1 copolymer for heat sealing film and resin composition comprising the same - Google Patents

Abstract

PURPOSE: Provided is a propylene-ethylene-butene-1 copolymer resin for a heat-adhesive film, which is excellent in a blocking-resistance and is used for a food packing. CONSTITUTION: The propylene-ethylene-butene-1 copolymer resin having a melting temperature of 127-135°C and a melting calorie of 65-83 J/g is produced by polymerizing propylene, ethylene, and butene-1 by a gas phase or a bulk slurry polymerization in the presence of a solid complex titanium catalyst, an organo aluminum cocatalyst, and an organo silicon compound as an outer electron donor (formula SiR1R2(OR3)2) having bulky two alkyl groups and two alkoxy groups. The ratio of the ethylene/the butene-1 is less than 1. In the formula, R1 is cyclopentyl, 3-propylpentyl, 1-cyclopentylpropyl, etc., R2 and R3 are an alkyl, a cycloalkyl, an aryl.

Description

Propylene-ethylene-butene-1 copolymer for heat-adhesive film and resin composition comprising same {PROPYLENE-ETHYLENE-BUTENE-1 COPOLYMER FOR HEAT SEALING FILM AND RESIN COMPOSITION COMPRISING THE SAME}

The present invention provides a gaseous phase without using a solvent for each monomer of propylene, ethylene, butene-1 in the presence of a solid complex titanium catalyst, an organoaluminum promoter, an organosilicon compound having two alkyl groups and two alkoxy groups as external electron donors. The present invention relates to a propylene-ethylene-butene-1 copolymer resin prepared by polymerization using a bulk slurry polymerization process and a resin composition comprising the same.

Unstretched polypropylene-based films are widely used in food packaging because of their low cost and excellent thermal adhesive properties. Increasing the production speed during packaging reduces the time required for thermal bonding, so the thermal bonding temperature of the polymer used at the high temperature or the thermal bonding layer should be low. However, adhesion at high temperatures may damage the film due to heat, and in the case of applying a low melting temperature polymer, such as propylene-ethylene-butene-1 copolymer, to the thermal bonding layer to lower the thermal bonding temperature, blocking occurs. There is a limit to speeding up. In this case, the cause of blocking is known to be due to the surface transition of low crystalline components of low molecular weight.

Conventionally, various methods have been used to solve this problem. An example is a method of mixing a blocking agent with a resin for thermal bonding. As the blocking agent used, silicon dioxide is the most widely used (EP-A-27 586, EP-A-189 242), cured silicone (EP-A-242 055), polyamide-6, polyamide-6 , 6, polyethylene terephthalate, polyethylene benzoate (DE-A-2 244) and the like may be used. However, excessive use of the antiblocking agent has a disadvantage in that the transparency or glossiness of the film is lowered, and in the case of less use, blocking occurs. In addition, the propylene-ethylene-butene-1 terpolymer prepared by solvent slurry polymerization has better blocking resistance than the copolymer by gas phase or bulk slurry polymerization, but has a disadvantage of high manufacturing cost.

An object of the present invention is to improve the above problems, the production cost is low by gas phase or bulk slurry polymerization, the crystallinity is high and the surface transition even at low melting temperature by using a specific external electron donor in the polymerization process Propylene-ethylene-butene-1 copolymer resin for heat-adhesive film which has low change of cloudiness during heat treatment, low blocking temperature and excellent blocking resistance and can be effectively applied even at high speed packaging. It is to provide a composition.

The propylene-ethylene-butene-1 copolymer resin of the present invention is a propylene, ethylene, butene-1 in the presence of a solid complex titanium catalyst, an organoaluminum promoter, an organosilicon compound having two alkyl groups and two alkoxy groups as external electron donors. Each monomer is characterized in that it is prepared by polymerizing using a gas phase or bulk slurry polymerization process without using a solvent.

The propylene-ethylene-butene-1 copolymer of the present invention prepared as described above has a molar ratio of ethylene / butene-1 of 1.0 or less, a melting temperature of 127 to 135 ° C and a heat of fusion of 65 to 83 J / g. As compared to the existing propylene-ethylene-butene-1 copolymer has the advantage of improved blocking resistance while maintaining a low thermal bonding temperature.

If the molar ratio of ethylene / butene-1 of the propylene-ethylene-butene-1 copolymer exceeds 1.0, the low crystalline component transfers to the surface during aging after the production of the heat-adhesive film, and blocking occurs. Even if the molar ratio of ethylene / butene-1 is 1.0 or less, the thermal bonding temperature is high when the melting temperature exceeds 135 ° C, and blocking occurs when the melting temperature is less than 127 ° C.

The solid complex titanium catalyst used in the production of the propylene-ethylene-butene-1 copolymer resin of the present invention is prepared by contacting a magnesium compound with a titanium compound, wherein the titanium compound is preferably tetrahalogenated titanium.

There is no restriction | limiting in particular as such a solid complex titanium catalyst, A well-known thing can be selected and used. In addition, as a cocatalyst in the polymerization process, an organoaluminum compound known to be used together with a solid complex titanium catalyst may be selected and used.

As an external electron donor used in the preparation of the propylene-ethylene-butene-1 copolymer resin of the present invention, an organosilicon compound represented by formula (I) having two alkyl groups and two alkoxy groups is used.

SiR ¹ R ² (OR ³ ) ₂ ---------------- (Ⅰ)

In the above formula, R ¹ is a cyclopentyl group, 2-methylcyclopentyl group, 3-methylcyclopentyl group, 2-ethylcyclopentyl group, 3-propylpentyl group, 3-isopropylcyclopentyl group, 3-butylcyclophene Tyl group, 3-tertarybutylcyclopentyl group, 2,2-dimethylcyclopentyl group, 2,3-dimethylcyclopentyl group, 2,5-dimethylcyclopentyl group, 2,2,5-trimethylcyclopentyl group, 2 , 3,4,5-tetramethylcyclopentyl group, 2,2,5,5-tetramethylcyclopentyl group, 1-cyclopentylpropyl group, 1-methyl-1-cyclopentylethane group, cyclopentenyl group, 2-cyclopentenyl group, 3-cyclopentenyl group, 2-methyl-1-cyclopentenyl group, 2-methyl-3-cyclopentenyl group, 3-methyl-3-cyclopentenyl group, 2-ethyl-3-cyclopentene Neyl group, 2,4-dimethyl-3-cyclopentyl group, 2,5-dimethyl-3-cyclopentenyl group, 2,3-4,5-tetramethyl-3-cyclopentenyl group, 2,2,5,5 -Tetramethyl-3-cyclopentenyl group, 1,3-cyclopentadienyl group, 2,4-cyclopentadienyl group, 1,4- Clopentadienyl group, 2-ethyl-2,4-cyclopentadienyl group, 2,2-dimethyl-2,4-cyclopentadienyl group, 2,3-dimethyl-2,4-cyclopentadienyl group, 2, 5-dimethyl-2,4-cyclopentadienyl group, 2,3,4,5-tetramethyl-2,4-cyclopentadienyl group and the like, R ² is an alkyl group, a cycloalkyl group, an aryl group and the like, and R ³ is It is an alkyl group, a cycloalkyl group, an aryl group, etc. It is preferable to use the organosilicon compound especially whose R <^1> and R <^2> are both cyclopentyl groups and R <^3> is a methyl group or an ethyl group. When an organosilicon compound having one bulky cycloalkyl group having 6 or more ring carbon atoms, one alkyl group and two alkoxy groups which are not cyclic compounds is used as an external electron donor, blocking occurs due to low crystallinity (melt heat amount) of the produced polymer. .

The polymerization method of the propylene-ethylene-butene-1 copolymer resin of the present invention uses a gas phase or bulk slurry polymerization process to improve the yield and reduce the production cost.

The resin composition for heat-adhesive films of the present invention is prepared by adding various additives for common heat-adhesive resin compositions such as heat stabilizers, antiblocking agents, neutralizing agents, and the like to the above propylene-ethylene-butene-1 copolymer resins.

There is no restriction | limiting in particular in the method of manufacturing the resin composition of this invention, The method of manufacturing the polypropylene resin composition generally known can be used. The copolymer resin and each additive component can be freely selected and mixed in a desired order. Usually, a method of kneading using a kneader such as a kneader, a roll, a short-barrier mixer, and a single or twin screw extruder by adding a copolymer resin and each component in a required amount may be used.

The copolymer resin and resin composition of this invention are used as a material of the plastic film for thermal bonding.

The heat-adhesive plastic film produced using the copolymer resin itself or the resin composition containing the same of the present invention can be molded by a conventional T-die method. Moreover, as a form of a plastic film, it is also possible to apply in the form of the multilayer film using the resin composition of this invention in both outermost layers or one outermost layer other than a single plastic film. Wetness may be improved by surface treatment such as corona discharge treatment or flame treatment during film production.

The present invention can be understood in more detail by the following examples and comparative examples, the following examples are only examples for illustrating the present invention and are not intended to limit the protection scope of the present invention.

The measuring method of the physical properties in each Example and a comparative example is as follows.

-Ethylene Content / Butene-1 Content: Infrared Absorption Spectroscopy

-MI: ASTM D1238, 230 ℃, 2.16㎏

-Melting temperature / melting heat amount: Using a Perkin Elmer DSC-7 type, 0.1mm press sheet is heated to 200 ° C once, cooled to 25 ° C at 10 ° C / min, and then 25 to 25 ° C at a heating rate of 10 ° C / min. The temperature Tm which measured to 200 degreeC and shows the maximum endothermic peak was DSC melting | fusing point, and the heat amount to 70 degreeC melting | fusing completion temperature was made into the heat of fusion.

-Cloudiness change during heat treatment: Copolymer resin is formed into 30㎛ film using normal draw-free film machine for laboratory, and this film is heat treated in 100 ℃ oven for 1 hour and then measured by cloudiness according to ASTM D1003. The difference value with the blurring degree was made into the blurring degree.

-Blocking force: The film was cut into an area of 10 cm 2, two films were overlapped, placed between two glass plates, and weighed 500 g / cm 2, and then the peel strength of the film was measured after heat treatment in an oven at 40 ° C. for 7 days. The lower the blocking force, the better the blocking resistance.

Heat bonding temperature: Two films are put between 12 micrometers polyethylene terephthalate films, and they adhere for 1.5 second under a load of 2 kgf. The bonded film is cut to a width of 10 mm to measure the interfacial peel strength of the film. The bonding temperature when the peel strength is 600 g is the thermal bonding temperature.

Each Example and the comparative example are shown in Table 1.

Example

The polymerization method of the propylene-ethylene-butene-1 copolymer resin of the Example is as follows.

A 2 liter high pressure reactor was washed with propylene, and then 27 mg of a solid complex titanium catalyst (0.02 mmol of titanium in terms of titanium atoms) were placed in a glass vial and placed in a reactor in a nitrogen / vacuum state. The vacuum was repeated three times. 0.1 mmol of dicyclopentyldimethoxysilane, an organosilicon compound having 10 mmol of triethylaluminum as cocatalyst and two bulky cycloalkyl and two alkoxy groups having 5 ring carbon atoms as external electron donor, together with 1000 ml of n-hexane Injected into. After hexane was injected, 100Nml of hydrogen was added thereto. Ethylene and butene-1 were sufficiently stirred at a molar ratio (see Table 1) to be applied to the reaction in a separate vessel connected to the reactor and then injected into the reactor. After the injection, the temperature was raised to 70 ° C., followed by injection of propylene gas, and the reaction was started by breaking the vial mounted in the reactor with the stirrer when the propylene became a gas-liquid equilibrium. The reaction was carried out for 30 minutes and after the reaction was completed, the contents of the high pressure product was cooled to room temperature, and about 10 ml of ethanol was injected to remove the catalyst active site. The polymer produced at this time was collected extraly and dried in a vacuum oven at 50 ° C. for about 6 hours to obtain a propylene-ethylene-butene-1 copolymer as a white powder.

Comparative example

As shown in Table 1, cyclohexyl, an organosilicon compound having one dicyclopentyldimethoxysilane or a bulky cycloalkyl group having 6 ring carbon atoms and an alkyl group and two alkoxy groups other than a cyclic compound, used in the examples as an external electron donor The polymerization was carried out in the same manner as in Example except that methyldimethoxy silane was used and the contents of ethylene and butene-1 were changed.

A: Dicyclopentyl dimethoxy silane

B: Cyclohexyl methyl dimethoxy silane

As can be seen from Table 1, Examples 1 and 2 have the same melting temperature and thermal bonding temperature as Comparative Example 1, but the heat of melting (crystallinity) is high, the cloudiness change and the blocking force are low during heat treatment.

In addition, even when the same external electron donor was used in the polymerization, Comparative Example 2, in which the melting temperature and the heat of fusion were higher than the range of the present invention, has a higher thermal bonding temperature compared to Example 1, in which the melting temperature and the heat of fusion were within the range of the present invention. .

In addition, Comparative Example 3 has the same melting temperature and the heat of fusion as the external electron donors used in Examples 1 and 2, but the ratio of ethylene / butene-1 is higher than 1.0, so that the cloudiness change and the blocking force are high during the heat treatment. The external electron donors used in Examples 1 and 2 are the same, and the ratio of ethylene / butene-1 is low, but the melting temperature and the amount of heat of melting are so low that the blocking force is high.

As can be seen from the above, the propylene-ethylene-butene-1 copolymer prepared by the present invention is prepared by gas phase or bulk slurry polymerization using an external electron donor capable of producing a polypropylene resin composition having high crystallinity. Inexpensive manufacturing cost, high crystallinity even at low melting temperature, low surface transition material, low cloudiness change during heat treatment, and excellent thermal resistance while maintaining low thermal bonding temperature.

Claims (4)

In the presence of a solid complex titanium catalyst, an organoaluminum promoter and an organosilicon compound having two alkyl groups and two alkoxy groups bulked as external electron donors, each of propylene, ethylene and butene-1 monomers is a gaseous or bulk-free solvent. Produced by polymerization in a slurry polymerization process, the propylene-ethylene for heat-adhesive film, characterized in that the molar ratio of ethylene / butene-1 is 1.0 or less, the melting temperature is 127 ~ 135 ℃, the heat of fusion 65 ~ 83J / g Butene-1 copolymer resin. The method of claim 1, wherein the external electron donor is an organosilicon compound represented by the following general formula (I) SiR ¹ R ² (OR ³ ) ₂ ---------------- (Ⅰ) R ¹ is a cyclopentyl group, 2-methylcyclopentyl group, 3-methylcyclopentyl group, 2-ethylcyclopentyl group, 3-propylpentyl group, 3-isopropylcyclopentyl group, 3-butylcyclopentyl group , 3-tertarybutylcyclopentyl group, 2,2-dimethylcyclopentyl group, 2,3-dimethylcyclopentyl group, 2,5-dimethylcyclopentyl group, 2,2,5-trimethylcyclopentyl group, 2, 3,4,5-tetramethylcyclopentyl group, 2,2,5,5-tetramethylcyclopentyl group, 1-cyclopentylpropyl group, 1-methyl-1-cyclopentylethp group, cyclopentenyl group, 2 -Cyclopentenyl group, 3-cyclopentenyl group, 2-methyl-1-cyclopentenyl group, 2-methyl-3-cyclopentenyl group, 3-methyl-3-cyclopentenyl group, 2-ethyl-3-cyclopentenyl group , 2,4-dimethyl-3-cyclopentyl group, 2,5-dimethyl-3-cyclopentenyl group, 2,3-4,5-tetramethyl-3-cyclopentenyl group, 2,2,5,5- Tetramethyl-3-cyclopentenyl group, 1,3-cyclopentadienyl group, 2,4-cyclopentadienyl group, 1,4-hour Lopentadienyl group, 2-ethyl-2,4-cyclopentadienyl group, 2,2-dimethyl-2,4-cyclopentadienyl group, 2,3-dimethyl-2,4-cyclopentadienyl group, 2, 5-dimethyl-2,4-cyclopentadienyl group or 2,3,4,5-tetramethyl-2,4-cyclopentadienyl group, R ² is an alkyl group, a cycloalkyl group or an aryl group, R ³ is an alkyl group, a cycloalkyl group or an aryl group, wherein the propylene-ethylene-butene-1 copolymer resin for heat-adhesive film. The propylene-ethylene-butene-1 copolymer resin for heat adhesive film according to claim 1, wherein the external electron donor is an organosilicon compound having two bulky cycloalkyl groups and two alkoxy groups having 5 ring carbon atoms. A resin composition for a heat-adhesive film, comprising a propylene-ethylene-butene-1 copolymer resin according to any one of claims 1 to 3, and common additives such as a heat stabilizer, an antiblocking agent, and a neutralizing agent.