KR20020006982A - Polyolefin resin composition for a blown film having a matt property, and a matt film using it - Google Patents

Abstract

PURPOSE: A polyolefin resin composition for a flat blown film and a flat film prepared by using the composition are provided, to reduce the gloss of the surface of a film, thereby improving the value and merchantability of products. CONSTITUTION: The polyolefin resin composition comprises 30-70 wt% of a copolymer resin of an α-olefin of C1-C10 and ethylene or an ethylene homopolymer resin which has a melt index of 0.01-0.4 g/10 min and a density of 0.930-0.970 g/cm¬3; 30-70 wt% of an impact polypropylene resin which comprises an ethylene-propylene copolymer and has a melt index of 0.1-10 g/10 min, or random polypropylene resin which comprises ethylene and/or 1-butene and has a melt index of 0.1-10 g/10 min; and optionally 10-300 ppm of peroxides. The flat film is prepared by blow molding the composition to form a surface layer of a product. Preferably the extrusion temperature is 180-250 deg.C.

Description

Polyolefin resin composition for a blown film having a matte property and a matte film manufactured using the same {Polyolefin resin composition for a blown film having a matt property, and a matt film using it}

The present invention relates to a polyolefin resin composition for a blown film having a matte property and a matte film prepared using the same, and more particularly, to a polyolefin resin composition capable of producing a film by a blown film forming method and having excellent matte properties. It relates to a matte film produced using a blown film forming method.

Polyolefin resin is a resin that balances economic and functional aspects. Films made of such polyolefin resin have excellent mechanical, thermal, and electrical properties, and are excellent in chemical resistance and formability, such as food packaging, product packaging, and paper. It is widely used worldwide as a coating material for other materials. In particular, matte films, which have a low surface gloss and impart a soft touch to the film to enhance the merchandise of the packaged material, are widely used as high value-added commodities. It manufactures using.

Matte development is caused by the diffuse reflection phenomenon by the unevenness | corrugation of a reflective surface, and the method described below can be used in order to provide a matte characteristic to the surface of a film.

First, the surface treatment of the surface of the general film by a method such as coating and etching,

Secondly, a method using the flowability, shrinkage and refractive index difference between the mixed resins, which is characteristic of the resin mixture having incompatibility;

Third, a method of applying unevenness to the surface by using inorganic materials, and

Fourth, the embossing process by giving unevenness to the cooling roll.

In general, the first method is not commonly used because it requires a separate post-processing equipment, such as coating and drying equipment, commercially, the second, third, fourth method, and mixing methods thereof are used.

In addition, a method of manufacturing a polyolefin film can be broadly divided into three types. The larger the melt index (MI) of the mixed resin is, the more commonly used to obtain advantageous matt characteristics, but generally requires a drawing process. Cast molding method using a straight die (T-die) has a limit to be adjusted so that the processing stability in the stretching process to a certain level or more; Because of low cost of manufacturing equipment and good balance of tear strength, excellent impact strength and tear strength, there is no need for blow film forming method and drawing process using round die, which is widely used. There is a relatively good method of forming an inflation film, which is also relatively inexpensive compared to other methods.

Among them, the blown film forming method has a limitation in that the bubble stability of the resin to be used is higher than or equal to a predetermined level because the film is manufactured by stretching the bubble.

US Pat. No. 5,560,885 describes a resin composition having matt properties and a molding technique thereof using a polyolefin mixture. According to the contents disclosed in the patent, the resin composition is biaxially stretched after sheet production by a casting molding method using an incompatible ethylene-alpha olefin copolymer and propylene-alpha olefin copolymer or a terpolymer blend thereof In this case, the stretching temperature is 40 to 100 占 폚 and the stretching ratio is 32 to 70 times. In addition, MI (melt index) of resin to be used is 1.5 g / min-12 g / min, Preferably it is known as 2.5-6 g / min.

In addition, U. S. Patent No. 5,473, 016 describes a resin composition capable of producing a film or sheet having matt properties, such a resin mixture comprising: 1) 10 to 80% by weight of a polyolefin copolymer having a MI of 1 to 20 g / min, 2) 5-30% by weight of a super low density ethylene-alphaolefin copolymer having a density of 0.86-0.91 g / cm ³ , and 3) 5-85% by weight of a modified polyolefin resin having a MI of 0.1-2.0 g / 10min. , The film is produced by the casting method.

Film produced by the casting method can be seen through the conventional literature, due to the effect of uniaxial or biaxial stretching, has a disadvantage of weak tear strength and impact strength, the process is complicated and the initial investment costs a lot of disadvantages, casting The film produced by the method has a disadvantage in that a second sealing process is required when manufacturing a packaging bag such as a shopping bag.

In addition, U.S. Patent No. 3,361,704 describes a method of adding matte properties to a polyolefin film by adding an inorganic material. In the case of adding 30 to 80% of an inorganic material, there is a phenomenon of deterioration of physical properties due to an inorganic material having no compatibility with a resin. By appearing, tearing, tensile strength, impact strength is lowered, there is a problem that requires a separate (compounding) equipment for mixing the inorganic material.

In addition, Korean Patent Application No. 2000-32370, filed by the present applicant, describes a method of manufacturing a matte film that can be manufactured using an inflation film molding method.

On the other hand, in the production of a polyolefin film having a matte property, in order to mold the blown film, the melt strength of the resin is high and MI is preferably 1 or less, but examples of the manufacture by the blow molding method using such materials are found. Can't.

As a result of the present inventor's study to solve the above-mentioned problems, the inventors have found a polyolefin resin composition having a matte property consisting of ethylene-alpha olefin copolymer resin and random polypropylene resin, and the present invention has been completed based on this.

Accordingly, an object of the present invention is to provide a polyolefin resin composition capable of producing a matte film having excellent matte properties by using a blown film forming method of a method different from the prior arts in the manufacture of a film having a matte property. .

In addition, another object of the present invention to provide a matte film for producing the polyolefin resin composition using a blown film molding method.

Polyolefin resin composition having a matte property of the present invention for achieving the above object has a melt index of 0.01 ~ 0.4g / 10min, a density of 0.930 ~ 0.970g / cm ³ and a copolymer of alpha olefin and ethylene having 1 to 10 carbon atoms Or 30 to 70% by weight of ethylene homopolymer resin; And an impact polypropylene resin having a melt index of 0.1 to 10 g / 10 min and a random polypropylene resin comprising ethylene and / or butene-1 and 70 to 30 wt%.

Matte film of the present invention for achieving the above another object, the melt index is 0.01 ~ 0.4g / 10min, the density is 0.930 ~ 0.970g / cm ³ and the carbon resin of 1 to 10 alpha olefin and ethylene copolymer or ethylene alone 30 to 70% by weight of polymerized resin; And a polyolefin having a matte property, having a melt index of 0.1 to 10 g / 10 min and consisting of an impact polypropylene resin comprising an ethylene-propylene copolymer or a 70 to 30 wt% random polypropylene resin comprising ethylene and / or butene-1. The resin composition is prepared using a blown film molding method.

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

As described above, the composition according to the present invention has a melt index of 0.01 to 0.4 g / 10 min, a density of 0.930 to 0.970 g / cm ³ and a copolymer of alpha olefin and ethylene having 1 to 10 carbon atoms or ethylene homopolymer resin ( First component) 30 to 70% by weight; And an impact polypropylene resin having a melt index of 0.1 to 10 g / 10 min and an ethylene-propylene copolymer or 70 to 30 wt% of a random polypropylene resin (second component) comprising ethylene and / or butene-1, And optionally 10 to 300 ppm (third component) of the peroxide.

In the resin mixture, a matrix phase is formed by using a first component of ethylene-alpha olefin copolymer resin or ethylene homopolymer resin having a very low melt index (ASTM D1238), thereby improving bubble stability of the resin mixture and It is possible to use a blown film forming method during the processing, such melt index of 0.01 ~ 0.4g / 10min, density of 0.930 ~ 0.970g / cm ³ and a copolymer of alpha olefin and ethylene having 1 to 10 carbon atoms or The usage-amount of resin chosen from ethylene homopolymerization resin is 30 to 70 weight%. If the melt index is less than 0.01g / 10min, it is difficult to process in the extruder, if it exceeds 0.4g / 10min there is a problem in the matte effect and bubble stability, if the density is less than 0.0930g / cm ^{3 the} matte effect is reduced there is a problem. In addition, when the content of the first component is less than 30% by weight or more than 70% by weight, the matt effect is reduced.

In addition, due to the difference in refractive index / flow / shrinkage with the first component, which is a matrix resin, as a dispersed phase, the second component added to impart unevenness to the film surface to give matt characteristics, has a melt index of 0.1 to An impact polypropylene resin of 10 g / 10 min and comprising an ethylene-propylene copolymer or a random polypropylene resin comprising ethylene and / or butene-1, including from 70 to 30% by weight, wherein If the melt index is less than 0.1g / 10min, the resin is not produced because of poor productivity, and if it exceeds 10g / 10min, the bubble stability becomes weak. If the content is less than 30% by weight or more than 70% by weight, the matt effect is achieved. There is a decreasing problem.

On the other hand, the matte properties of the resin is primarily because the greater the difference between the melt index of the first component and the second component, the better the matte characteristics due to the phase separation and surface roughness due to the difference in viscosity and flowability.

In addition, since it acts as a compatibilizer of polypropylene and polyethylene to reduce the size of the phase-separated dendritic phase to provide a soft touch visual characteristics, such a component necessary for controlling the visual feel of the matte film surface to the resin composition The three components include 10 to 300 ppm more selectively as peroxides. At this time, if the content of the peroxide is less than 10 ppm, there is little effect of addition, and if it exceeds 300 ppm, odors and foreign substances may be generated.

The processing equipment and processing conditions for producing the polyolefin resin composition having a matte property composed of the first component to the third component into the matte film are a blown film device for producing a polyolefin film of a single layer or a multilayer which is commonly used. Blown film machine for film production, such as medium / low density polyethylene (polyethylene vinyl acetate resin), and the processing conditions are 180-250 ° C. of the resin extruded from the die, and resin extruded from the die. If the temperature is less than 180 ℃ melt fracture (melt fracture) occurs on the film surface does not multiply the surface of the film, if it exceeds 250 ℃ bubble stability is lowered, it is impossible to form a uniform film. In addition, the bubble up ratio (BUR) is 0.9 to 3.0, and the higher the BUR, the better the balance between the physical properties of the film in the machine direction and the direction of the machine resin, but exceeding 3.0 deteriorates the stability of the bubble.

In addition, the film produced using the blown film device for producing a single layer or multi-layer polyolefin film forms a single layer or a multilayer structure, and the composition constitutes the surface layer of the film, when the film is a multilayer structure, at least one Surface layer can be achieved.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited thereto.

Examples 1-2

The resin composition containing each component according to Table 1 was kneaded at 200 ° C. using a 30ψ twin screw compounder, and a matt film was prepared using a low density polyethylene blown film forming machine. At this time, die temperature was 200 degreeC and BUR was 1.6. In order to measure the properties of the manufactured matte film, the glossiness (gloss), bubble stability results with a glossiness detector (gloss detector) is shown in Table 1 below.

At this time, the matte property is the value when light is reflected on the test material at a certain angle (45 °) and the reflected light is received at the same angle as the incident light. ).

Comparative Example 1

To prepare a film was carried out in the same manner as in the above-described resin composition composed as shown in Table 1, the analysis results thereof were compared to Table 1 below.

Composition rain Gloss Bubble stability First ingredient Second ingredient Comparative Example 1 100% Density = 0.919MI = 1.0 - 25 (bottom) medium Example 1 50% Density = 0.954MI = 0.047 50% C ₂ = 5.9% MI = 0.5 6.8 (up) medium Example 2 50% Density = 0.945MI = 0.33 50% C ₂ = 5.9% MI = 0.5 7.3 (up) medium

As can be seen in Table 1, it can be seen that the film according to the present invention exhibits excellent matt properties, compared to the film of the comparative example.

As can be seen through the above examples and comparative examples, the film produced according to the present invention has fine matte irregularities formed on the surface is diffusely reflected light has excellent matt properties, even processing with a general blown film forming machine Higher quality matte film can be produced.

Claims (6)

A melt index of 0.01 to 0.4 g / 10 min, a density of 0.930 to 0.970 g / cm ³ , and a copolymer resin of alpha olefin and ethylene having 1 to 10 carbon atoms or 30 to 70 wt% of ethylene homopolymerization resin; And Matte characteristics, characterized in that the melt index is 0.1 to 10g / 10min and comprises 70 to 30% by weight of an impact polypropylene resin containing an ethylene-propylene copolymer or a random polypropylene resin containing ethylene and / or butene-1 Polyolefin resin composition for blown films having a. The polyolefin resin composition for a blown film having a matte property according to claim 1, wherein the composition further comprises 10 to 300 ppm of a peroxide. A melt index of 0.01 to 0.4 g / 10 min, a density of 0.930 to 0.970 g / cm ³ , and a copolymer resin of alpha olefin and ethylene having 1 to 10 carbon atoms or 30 to 70 wt% of ethylene homopolymerization resin; And a polyolefin having a matte property including a melt index of 0.1 to 10 g / 10 min and an impact polypropylene resin comprising an ethylene-propylene copolymer or 70 to 30 wt% of a random polypropylene resin comprising ethylene and / or butene-1. Matte film, characterized in that the resin composition was prepared by forming a surface layer using a blown film forming method. 4. The matte film of claim 3, wherein the composition further comprises 10-300 ppm of peroxide. The matt film according to claim 3, wherein the molding method is performed at a temperature of 180 to 250 ° C. and a BUR of a bubble is performed at a condition of 0.9 to 3.0. 4. The matte film of claim 3, wherein the resin composition forms at least one surface layer when the film has a multilayer structure.