KR101484854B1 - Polypropylene resine composition for heat seal and multi-layer film using the same - Google Patents

Abstract

The present invention relates to a polypropylene resin composition for heat bonding with excellent heat bonding, transparency and a high crystallization temperature. More specifically, a polypropylene resin composition for heat bonding comprises (A) 100 parts by weight of crystalline ethylene-propylene-1-butene terpolymer whose melting point is between 125 and 135 degree Celsius; (B) 1-10 parts by weight of ethylene alpha-olefins copolymer whose density is 0.85-0.92 g/cm^3 and which is manufactured by a single-site catalyst; (C) and 0.1-0.5 parts by weight of an organic nucleating agent.

Description

TECHNICAL FIELD The present invention relates to a polypropylene resin composition for heat bonding and a multilayer film using the same,

The present invention relates to a polypropylene resin composition for thermal bonding and a polypropylene multilayer film using the same.

The unleaded polypropylene film is widely used in food packaging because of its low cost and excellent thermal adhesiveness. Increasing the production speed in packaging reduces the time required for thermal bonding, so the bonding temperature or the thermal bonding temperature of the resin used in the thermal bonding layer should be low. Adhesion at high temperatures can damage the film by heat, so resins with low thermal bond temperatures should be used.

The heat bonding temperature is related to the melting temperature of the resin, and the lower the melting temperature, the lower the heat bonding temperature. However, if a low melting temperature is used, the number of low crystalline materials may increase, which may cause blocking of the film, and it is difficult to manufacture a resin having an infinitely low melting temperature because of limitations in the production process. Therefore, it is advantageous to apply a propylene-ethylene-butene-1 terpolymer less in the low-crystallization substance than the propylene-ethylene copolymer to the heat-bonding layer, and it is generally preferable to use a polypropylene resin having a melting temperature of 125 to 135 ° C A terpolymer of ethylene-1-butene is used. The related domestic patent is Patent Application No. 98-08160.

However, also in this case, various problems arise depending on the film processing equipment and processing conditions. The lower the melting temperature, the lower the amount of the low-crystalline materials increases, the transition to the surface causes blocking, and the lower the melting temperature of the resin, the lower the crystallization temperature, and the resin is discharged from the die, A roll mark is generated when a plate-out roll is brought into contact with the plate-out roll. In the case of transparent film applications, these marks are a problem for post-processing companies.

In order to improve the blocking resistance of the film, there is generally a method of mixing an anti-blocking agent with the resin. Silicon dioxide is the most widely used anti-blocking agent (EP-A-27 586, EP-A-189 242), cured silicone (EP-A-242 055), polyamide- , 6, polyethylene terephthalate, polyethylene benzoate (DE-A-2 244) or the like may be used. However, if the blocking agent is used excessively, the transparency and gloss of the film deteriorate.

Another method of increasing the thermal adhesion is disclosed in European Patent No. 27586, which discloses polypropylene for thermal bonding comprising a long chain of aliphatic amines and polydialkyl siloxanes in an ethylene copolymer , And a thermally adhesive polypropylene resin composition in which an ethylene-alpha olefin copolymer is mixed with a propylene-ethylene-butene-1 terpolymer is disclosed. However, the film produced by such a resin composition has a high- There is a disadvantage in that problems arise in the packaging machine or the processing machine of the film, and transparency of the film is deteriorated.

An object of the present invention to solve the above problems is to provide a polypropylene resin composition which is excellent in thermal adhesiveness and can be packaged in a film at a low heat bonding temperature and has a high crystallization temperature while maintaining transparency.

According to an aspect of the present invention,

(A) 100 parts by weight of a crystalline ethylene-propylene-1-butene terpolymer having a melting temperature of 125 to 135 ° C; (B) 1 to 10 parts by weight of an ethylene-alpha olefin copolymer made from a single-site catalyst having a density of 0.85 to 0.92 g / cm 3; And (C) 0.1 to 0.5 parts by weight of an organic nucleating agent.

The present invention also provides a multilayer film produced using the polypropylene resin composition.

Since the polypropylene resin composition according to the present invention has a low heat bonding temperature, it is possible to reduce the consumption of heat energy by reducing the amount of heat energy consumed during film packaging processing, to have a high degree of crystallization while maintaining transparency, It is possible to provide a polypropylene multilayer film.

Hereinafter, the present invention will be described in more detail.

The polypropylene resin composition of the present invention is characterized by comprising 100 parts by weight of the following component (A), 1 to 10 parts by weight of the component (B), and 0.1 to 0.5 parts by weight of the component (C).

(A) a crystalline ethylene-propylene-1-butene terpolymer having a melting temperature of 125 to 135 DEG C,

(B) an ethylene-alpha olefin copolymer prepared with a single-site catalyst having a density of 0.85 to 0.92 g / cm 3,

(C) Organic nucleating agent.

The polypropylene-based resin used in the present invention is a crystalline ethylene-propylene-1-butene terpolymer having propylene as a main component and has a melting temperature of 125 to 135 캜 and excellent thermal adhesiveness. A polypropylene resin having a melting temperature of less than 125 占 폚 has a difficulty in the production process, and a resin having a melting temperature of more than 135 占 폚 is poor in heat adhesion. The MI (230 ° C) of the resin is 6 to 8 g / 10 min and has flowability for a general unoriented polypropylene film.

The ethylene-alpha olefin copolymer used in the present invention has a density of 0.85 to 0.92 g / cm3. If the density is less than 0.85 g / cm 3, the low crystalline material is transferred to the film surface to deteriorate the film's blinking property. If the density is more than 0.92 g / cm 3, transparency of the film is reduced. The MI (190 DEG C) of the ethylene-alpha olefin copolymer is preferably 1 to 10. When the MI is less than 1 or exceeds 10, the dispersibility with the polypropylene-based resin decreases, resulting in poor thermal adhesion and transparency. In addition, the ethylene-alpha olefin copolymer should be made from a single-site-point catalyst (SSC). However, the ethylene-alpha olefin copolymer prepared with the Ziegler-Natta catalyst increases the amount of low-crystalline materials,

In the present invention, 1 to 10 parts by weight of the ethylene-alpha olefin copolymer is suitably added to 100 parts by weight of the polypropylene resin, and 3 to 7 parts by weight is preferable in order to exhibit excellent physical properties. When the amount of the ethylene-alpha olefin copolymer is less than 1 part by weight, there is no increase in thermal adhesiveness. When the amount is more than 10 parts by weight, phase separation occurs between the polypropylene resin and the ethylene- alpha olefin copolymer, Deviation occurs.

In the present invention, an organic nucleating agent is used for improving transparency. Examples of the organic nucleus agent include bisbenzylidene sorbitol, bismethylbenzylidene sorbitol, bisethylbenzylidene sorbitol, 1,2-chloro-2,4-methylbenzylidene sorbitol, 1,3,2,4- 4-dimethylbenzylidene sorbitol and the like, and it is preferable to use bis 4-propylbenzylidene propyl sorbitol nucleus agent or bicycloheptane dicarboxylic acid nucleating agent. When the content of the organic nucleating agent is less than 0.1 parts by weight, transparency is not exhibited. When the amount is more than 0.5 parts by weight, there is little improvement in transparency as compared with an excess amount. It is particularly preferable to add 0.1 to 0.5 parts by weight of bis-4-propylbenzylidene propyl sorbitol to the resin composition of the present invention.

Various additives such as an antioxidant, a neutralizing agent, an anti-blocking agent and the like may be added to the resin composition of the present invention within a range that does not deviate from the characteristics of the present invention.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited thereto. The properties of the examples and comparative examples were measured by the following methods and standards.

Thermal bonding  Temperature ( Heat sealing 온도 )

The film was allowed to stand for 24 hours in a temperature and humidity chamber at a temperature of 23 ± 1 ° C and a humidity of 50 ± 5%. The two specimens were bonded to each other at a pressure of 2 kg / Measure the temperature at which the heat bonding between the two specimens begins to peel off.

Crystallization temperature  ( Crystallization 온도 )

The sample was maintained at 200 DEG C for 7 minutes using differential scanning calorimetry and then the crystallization temperature was measured while cooling to 40 DEG C at a rate of 10 DEG C / min.

Cloudiness ( Haze )

ASTM D 1003 conditions.

Plate out  role( Plate - Out Roll ) Local observation

After the condition that a roll mark is generated in the processing of the resin 1 through the unleaded polypropylene (CPP) film extruder was fixed, it was observed whether or not a roll mark occurred in the experiment of the Example / Comparative Example.

Example 1

An antioxidant, an antifoaming agent and an antioxidant are added to 100 parts by weight of the component (a) as an additive. 4 parts by weight of the component (c) and 0.2 parts by weight of the component (g) are added thereto and mixed by a mixer. To obtain a pellet-like composition. This composition was extruded at a melting temperature of 230 占 폚 using an extruder having a diameter of 45 mm and a T-die and rapidly cooled by a cooling roll with a surface temperature of 40 占 폚 to form a film to obtain a rolled film having a winding thickness of 30 占 퐉 and a width of 40 cm.

Example  2 and 3

As shown in Table 1, a polypropylene film was obtained in the same manner as in Example 1, except that the addition amounts of the component (c) and the component (g) were changed. Their properties are shown in Table 2.

Comparative Example  1 to 7

As shown in Table 1, the film was obtained through the experiment according to Example 1 by changing the content and the components of the resin to be added. The film properties thereof are shown in Table 2.

division Component (a) Component (b) Component (c) Component (d) Component (e) Component (f) Component (g) Example 1 100 - 4 - - - 0.2 Example 2 100 - 8 - - - 0.2 Example 3 100 - 4 - - - 0.4 Comparative Example 1 100 - - - - - - Comparative Example 2 - 100 4 - - - 0.2 Comparative Example 3 100 - 4 - - - - Comparative Example 4 100 - 15 - - - 0.4 Comparative Example 5 100 - - 4 - - 0.2 Comparative Example 6 100 - - - 4 - 0.2 Comparative Example 7 100 - - - - 4 0.2

week)

1) Component (a): Propylene-ethylene-butene-1 terpolymer, melting temperature 130 DEG C, MI (230 DEG C) = 7.0 g / 10 min

2) Component (b): Propylene-ethylene-butene-1 terpolymer, melting temperature 120 DEG C, MI (230 DEG C) = 7.0 g / 10 min

3) Component (c): an ethylene-alpha olefin copolymer prepared with a single active site catalyst,

Density 0.91 g / cm < 3 > MI (190 DEG C) = 5.0 g / 10 min

4) Component (d): an ethylene-alpha olefin copolymer prepared with a Ziegler-Natta catalyst,

Density 0.91 g / cm 3, MI (190 ° C) = 5.0 g / 10 min

5) Component (e): an ethylene-alpha olefin copolymer prepared with a single active site catalyst,

Density 0.93 g / cm 3, MI (190 ° C) = 5.0 g / 10 min

6) Component (f): low density polyethylene, Density 0.92 g / cm 3, MI (190 ° C) = 7.0 g / 10 min

7) Component (g): Bis 4-propylbenzylidene propyl sorbitol nucleus

division Heat bonding temperature (캜) Crystallization temperature (캜) Haze (%) Plate-out roll marks Example 1 125 109 One Not occurring Example 2 125 109 One Not occurring Example 3 125 112 2 Not occurring Comparative Example 1 130 90 5 Occur Comparative Example 2 120 95 One Not occurring Comparative Example 3 125 110 10 Occur Comparative Example 4 123 105 5 Not occurring Comparative Example 5 128 108 One Not occurring Comparative Example 6 130 113 3 Not occurring Comparative Example 7 128 108 2 Not occurring

Note) As the heat bonding temperature is lowered to a temperature at which the heat bonding strength value is 0.6 kg, the heat bonding property is excellent.

As shown in Table 2, a film prepared from a composition prepared by adding 1 to 10 parts by weight of the component (c) and 0.1 to 0.5 parts by weight of the component (g) using the component (a) Were superior to the comparative examples.

Claims (4)

(A) 100 parts by weight of a crystalline ethylene-propylene-1-butene terpolymer having a melting temperature of 125 to 135 ° C;
(B) 1 to 10 parts by weight of an ethylene-alpha olefin copolymer made from a single-site catalyst having a density of 0.85 to 0.92 g / cm 3; And
(C) 0.1 to 0.5 parts by weight of an organic nucleating agent,
Wherein the organic nucleating agent is bis 4-propylbenzylidene propyl sorbitol nucleating agent or bicycloheptane dicarboxylic acid nucleating agent. The method according to claim 1,
Wherein the ethylene-alpha olefin copolymer has a melt index of 1 to 10 g / 10 min (190 DEG C). delete A multilayer film made from the polypropylene resin composition of any one of claims 1 to 2.