KR100186293B1 - Propylenic resin sheets and process for preparing the same - Google Patents

Abstract

The present invention relates to a propylene resin sheet and a method for producing the same. Propylene resin sheet containing 0.01 to 5% by weight of ethylene resin and amine compound based on the total composition has excellent transparency, weather resistance, good post-processing and printability, It can be used as a substrate.

Description

Propylene Resin Sheet and Manufacturing Method Thereof

The present invention relates to a propylene resin sheet and a method for manufacturing the same. Specifically, the propylene resin sheet is excellent in transparency, weather resistance, good post-processing and printability, and can be used as a base material for various outdoor advertising papers, decorative interior papers, and high-grade cases. A sheet and a manufacturing method thereof.

As the industrial society diversifies, the necessity of various advertisements and promotions increases, and the demand for outdoor flyers, decorative interior papers, and packaging cases is constantly increasing. Nowadays, products made of polyvinyl chloride or paper are mainly used in such applications because of their low cost and ease of handling.

However, polyvinyl chloride is advantageous in that it is transparent and inexpensive to manufacture, but its use is limited because chlorine gas is generated to contaminate the environment during combustion. In addition, the paper is difficult to be stored for a long time in a place where the humidity or temperature fluctuations are large, and the yellowing phenomenon occurs due to the additives added for the brightening effect, and thus the use of the paper is limited.

Accordingly, as a result of research on a material that can replace polyvinyl chloride or paper, the use of polystyrene, polyethylene terephthalate, and polypropylene as a material having transparency that can clearly display the contents and weather resistance that does not change for a long time Limited.

Among them, polystyrene has good transparency and mechanical properties, but has a disadvantage in that odor is severe in the manufacturing process, black smoke and dust during incineration, and manufacturing costs are high.

Polyethylene terephthalate, another plastic material, is high quality due to its high gloss properties, but it is used only for some special applications because it is expensive and stiff and difficult to finish.

In accordance with these problems, research is being actively conducted on colorless, harmless, and low-cost resins, and polyolefin-based resins are in the spotlight as general-purpose resins. Among these, polypropylene has a density of 0.90 to 0.92 g / cm 3, which is the lightest and most transparent plastic among general purpose plastics, and has excellent heat resistance, electrical insulation, chemical resistance, flex resistance and post-processing properties, and is harmless. The range of use and the amount of is increasing rapidly.

On the other hand, ultraviolet rays (290 to 400 nm) present in nature act to decompose elemental bonds in the polymer. That is, when the polymer resin is exposed to light, it is decomposed to generate ketone groups, peroxides, or decomposed molecular chains are double-bonded. In addition, the newly formed material or functional group absorbs the wavelength in the ultraviolet region to promote decomposition of molecular chains in the resin to generate free radicals, and the generated radicals cause photoacidification to cause discoloration or deterioration of physical properties.

In order to prevent deterioration of the resin due to ultraviolet rays, a method of converting incident ultraviolet rays into thermal energy by adding an inorganic substance capable of absorbing ultraviolet rays in the resin and a method of blocking ultraviolet rays by adding carbon black are used. However, these materials have a problem of lowering the transparency of the resin.

Accordingly, an object of the present invention is to provide a propylene resin sheet which is excellent in transparency and weather resistance and suitable for use as a base material for various outdoor advertising papers, decorative interior papers, and high-grade cases.

In order to achieve the above object, the present invention provides a proplin-based resin sheet comprising 0.01 to 5% by weight of an amine-based compound having an ethylene-based resin and a hindered group with respect to the total composition.

Another object of the present invention is to provide a method for producing a propylene resin sheet which is excellent in transparency and weather resistance, has good post-processability and printability and can be used as a base material for various outdoor advertising papers, decorative interior papers and high-grade cases.

In order to achieve the above another object, in the present invention, the propylene-based resin, the low molecular weight ethylene-based resin, and the hindered group having a molten resin of 1 to 20 (g / 10 minutes) have a weight ratio of 99.98-90: 0.01-- 5: melt mixed to be 0.01-5, and then extruding; And rapidly cooling and solidifying the melt sheet extruded in the above step in a cooling roll, and then forming the propylene resin sheet.

Examples of the propylene resin usable in the present invention include polypropylene or copolymers with other olefins. In addition, a propylene resin has a melt index of 1 to 20 (g / 10 minutes) and a melting temperature of 130 to 150 ℃, the composition ratio is 80 to 97 mol% of propylene, 3 to 20 mol of olefins other than propylene It is preferable that it is%. Preferred examples include propylene-ethylene copolymers, propylene-butene copolymers, propylene-ethylene-butene copolymers, and the like.

The low molecular weight ethylene resin used in the present invention has a melt index of 20 to 40 (g / 10 minutes) and a melting temperature of 90 to 130 ° C. Polyethylene (LLDPE), ethylene-vinylacetate copolymer (EVA), and the like.

Moreover, it is preferable that the addition amount is 0.01 to 5 weight% with respect to a sheet. If it exceeds 5% by weight, it is poor in uniform kneading with propylene-based resin, so that bubbles are generated on the surface of the sheet or many poor appearance parts called die lines are formed, and low molecular ethylene-based materials are transferred to the surface. This is because the amount of resin is so increased that it adheres to the belt surface or the friction between sheet mirror surfaces becomes large.

The sterically hindered amine compound contained in the sheet according to the present invention is for terminating the radical reaction in the resin to improve weather resistance, preferably phenyl-naphthylamine, diphenylamine, N, N'-diphenyl-p-phenylenediamine, N, N'-di-β-naphthyl-p-phenylenediamine, p-hydroxyoxy-di-phenylamine, 2, 2, 4-trimethylhydroquinone , N, N'-phenylcyclohexyl-p-phenylenediamine, p-hydroxyoxyphenyl-β-naphthalamine, and the like.

In addition, the addition amount is 0.01 to 5% by weight based on the sheet, which is less than 0.01% by weight of the present invention, the effect of the present invention is less than 5% by weight is difficult to adhere to the belt and the phenomenon of transition to the surface occurs This is because the transparency of the sheet can be reduced.

In addition, in the propylene resin sheet of the present invention, well-known additives, for example, an antistatic agent, a dispersant, a slip agent, an antioxidant, an ultraviolet stabilizer, and the like may be added within a range that does not impair the effects of the present invention.

Hereinafter, the features of the present invention will be described in more detail through the manufacturing process of the sheet.

In order to manufacture the sheet of the present invention, first, the propylene resin and the low molecular ethylene resin are mixed, and then an amine compound is added. In this case, the mixing method may be either dry mixing or melt mixing, but a melt mixing method in which each resin may be uniformly mixed is preferable.

Subsequently, the sheet is manufactured by melting and extruding the mixed resin, followed by molding. In this case, it is desirable to maintain the extrusion temperature within the range of 170 to 220 ° C. under the condition of 100 to 150 screw rpm, which means that when the extrusion temperature is less than 170 ° C., an unmelted resin is formed to damage the belt or the sheet surface. This is because the photooxidation resistance may be deteriorated due to the foaming phenomenon due to thermal decomposition of the additives added in the resin when it is rough and exceeds 220 ° C. Under such conditions, the extrusion amount is preferably kept in the range of 250 to 300 kg per hour.

Cooling of the extruded sheet is preferably made through a cooling roll of 15 to 30 ℃. This means that the sheet has excellent transparency due to quenching at less than 15 ℃, but it is difficult to form efficiently due to the reverse winding phenomenon, and if it exceeds 30 ℃, crystals on the surface of the sheet may become too large due to slow cooling of the melt sheet. Because there is.

In addition, the molding machine is not particularly limited as long as it is conventionally used, in particular triangle ( Belt type sheet forming machine is preferred.

On the other hand, high glossiness of the surface of the sheet is one of the most important factors in order to improve the transparency of the sheet, which can be solved by mirroring the surface of the roll or belt in contact with the sheet and sufficiently close the sheet to the mirror surface. To this end, the resin must be molded into sheets while inducing a high pooling phenomenon (banking phenomenon).

According to the present invention, in order to solve the problem that the glare caused by the reflection of the surface is so large that the quality of the sheet looks low, the sheet may be reheated using a roll having irregularities. In this case, the shape, depth, and the like of the unevenness can be varied depending on the use of the sheet to be manufactured.

In detail, it is preferable that the unevenness formed according to the present invention has a unit plane of 10 to 1000 µm ² , and a shape having a depth of 0.1 to 10.0 µm so as to be 0.01 to 0.1 mm apart. In addition, the irregularities may be formed in various shapes such as pyramids, diamonds, cones, spheres, ellipses, etc. in the form of embossed or engraved, preferably double embossed.

When the sheet is reheated using a roll having such a shape, the surface of the sheet is embossed in the process. In this case, the reheating condition is preferably such that the sheet adheres at a pressure of 1 to 10 kg / cm 2 at a roll surface temperature of 50 to 70 ° C., which is less than 50 ° C., so that the shape transfer to the sheet surface is difficult, and 70 ° C. This is because the resin may adhere to the roll when it exceeds the surface gloss may be worse. In addition, the reheat treatment process according to the present invention can be performed at any position in the sheet manufacturing process.

The sheet of the present invention prepared under such process conditions has a luxurious atmosphere with inner and outer surface gloss of 120% or more and 30 to 60%, respectively, and has a crystal size of 250 to 1000 GPa and a surface crystallinity of 60 to 80%. For reference, when the size of the crystal is less than 250 kPa, the transparency is excellent, but the crystal structure is too fine, the heat resistance is not good, and if the crystal size exceeds 1000 kPa transparency is inferior. In addition, when the surface crystallinity is less than 60%, mirror entanglement occurs, and when it exceeds 80%, the sealing temperature increases and cracking occurs severely during the post-process.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not necessarily limited thereto.

Various performance evaluation of the sheet | seat manufactured by the Example and comparative example of this invention was performed by the following method.

1) Crystallinity

Using a density gradient tube consisting of carbon tetrachloride and normal heptane, the density (χ) was measured by an up-and-down method under a temperature condition of 25 ° C., and then calculated by the following equation.

2) crystal size

The diffraction intensity by angle was measured using a PCGAKU X-ray diffractometer (model name: D-MAX3C), and then the crystal size was calculated.

3) haze

Using a Hadometer of Gardner Neotek Co., Ltd. (USA), the scattered light and transmitted light values were measured using a C-light source and calculated according to the following equation.

4) glossiness

It was measured using a gloss meter (model name: GC-4010) of Gardner Neotek (USA) (reference diameter: black diameter, measuring strength: 60 degrees).

5) Surface Roughness

Measurement was performed using a contact type two-dimensional surface roughness measuring instrument (model name: SE-30D) manufactured by Kosaka Corporation (Japan).

6) Weatherability Assessment

Using the ultra-promoting weather tester (model name: UVP-2) from Amki Electric Co., Ltd. (Japan), the physical properties were evaluated for each change over time. For exposure to ultraviolet light, 260 hours is equivalent to one year. Considered.

7) Visual evaluation

The surface state of the molded sheet was visually identified.

8) Melt Index Evaluation

Resin samples were loaded and measured according to the method of ASTM D1238 under conditions of temperature and load specified in ASTM D1238 using a rheometer from DuPont, USA.

(Example 1)

99.2 g of random polypropylene resin having a melt index of 12 (g / 10 min) and a melting temperature of 145 ° C., 0.3 g of low density polyethylene, and 0.5 g of N, N'-di-β-naphthyl-p-phenylenediamine as an antioxidation agent Was mixed. The obtained resin mixture was discharged at a screw rpm of 120 at a speed of 270 kg per hour under an extrusion temperature of 200 ° C., cooled on a cooling roll at 25 ° C., and then heat-treated by bringing it into close contact with a rotating metal belt at a speed of 20 (m / min). Through the process to prepare a propylene resin sheet of the present invention.

Various physical properties of the prepared sheets were measured and shown in the table. The inner and outer surface glossiness was 135/42%, haze 2.5%, crystallinity 75%, crystal size 650Å, and the sheet was unique even after 5 years of outdoor storage. There was no change in physical properties.

(Example 2-5)

In the same manner as in Example 1, the sheet was prepared by changing the production conditions within the scope of the present invention as shown in the table, but the physical properties of the prepared sheet were generally good.

(Comparative Example 1-6)

In the same manner as in Example 1, the sheet was prepared by changing the manufacturing conditions outside the scope of the present invention as shown in the table. As shown in the table, the prepared sheets are not good at haze, crystal size, weather resistance, surface condition, and the like.

As can be seen from the above, the propylene resin sheet produced according to the present invention has excellent transparency, weather resistance, good post-processing and printability, and can be used as a base material for various outdoor advertising papers, decorative interior papers, and high-grade cases.

Claims (4)

99.98-90% by weight of random propylene resin having a melt index of 1-20 (g / 10min) and a melting temperature of 130-150 ° C, a melt index of 20-40 (g / 10min) and a melting temperature of 90-130 0.01-5.0% by weight of the low molecular weight ethylene-based resin and 0.01-5.0% by weight of the amine compound having a hindered group, the crystal size of the surface is 250-1000Å, the crystallinity is 60-80% Propylene-based resin sheet made with. The propylene-based resin sheet according to claim 1, wherein the ethylene-based resin is one selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, and ethylene vinyl acetate. The amine compound of claim 1, wherein the amine compound having a sterically hindered group is phenyl-naphthylamine, diphenylamine, N, N'-diphenyl-p-phenylenediamine, N, N'-di-β-naphthyl p-phenylenediamine, p-hydroxyoxy-di-phenylamine, 2, 2, 4-trimethylhydroquinone, N, N'-phenylcyclohexyl-p-phenylenediamine and p-hydroxyoxyphenyl- Propylene-based resin sheet, characterized in that one selected from the group consisting of β-naphthalamine. The method of claim 1, wherein the random propylene-based resin is a copolymer of at least one olefin and a propylene monomer selected from the group consisting of ethylene and butene.