KR100753995B1 - Polyethyleneterephtalate sheet for packaging which has good surface slip property, transmittance, and water-resistance - Google Patents

Abstract

A packaging PET(Polyethylene Terephthalate) sheet is provided to improve anti-blocking property and printing efficiency by using polymer particle with the similar refractive index of PET resin and acryl resin, and to prevent blocking in winding the sheet in the form of a roll or making a flat sheet. A surface of the packaging PET sheet(30) with good surface slip property, transparency, and water resistance is coated with coating solution produced by stirring polymer particle together with hydrophobic acryl emulsion. The hydrophobic acryl emulsion is produced by using methacryl monomer and vinylacetate monomer. The polymer particle consists of PMMA(polymethylmethacrylate), polystyrene, polyester, or polyurethane and has a mean particle diameter of 0.1~20 micrometers.

Description

Polyethylene terephthalate sheet for packaging which has good surface slip property, transmittance, and water-resistance

1 is a view for explaining a process of coating using a coating liquid according to the present invention.

<Description of reference numbers for the main parts of the drawings>

10: Gravure Roll Coater

20: coating layer

30: polyethylene terephthalate sheet

40: polymer beads

The present invention relates to a polyethylene terephthalate sheet, and relates to a polyethylene terephthalate sheet having excellent surface slipperiness, transparency, printability, and water resistance.

Recently, packaging containers for cosmetics and household goods have been developed in various designs and quality has been improved in order to stimulate consumer's desire to purchase. Therefore, the material of the clear box for cosmetic packaging or the packaging box of household goods also requires the quality of transparency and printability. The sheet used to make such a box is typically extruded by an in-line process, wound on a roll or made into a flat plate, and has a thickness of about 0.1 to 2 mm. In addition, due to processability and environmental problems, polyester resin, in particular, polyethylene terephthalate resin is mainly used.

However, if the surface is not slippery when cutting or processing the manufactured sheet, it is difficult for the cutter blade to chop several sheets at once, resulting in a problem that productivity is lowered. This slippery property is called blocking. This breaking phenomenon refers to a phenomenon in which a considerable resistance occurs due to the adhesion of more than just close contact with each other when the pressure applied in the vertical direction of the overlapping sheet or film and pulled in the opposite directions. The composition of this resistance depends on various complex environmental factors such as static electricity, mutual affinity, surface structure. In general, inorganic particles such as talc or silica are used as an anti-locking agent, but this often causes a problem that transparency is impaired.

On the other hand, if printability is bad in such a packaging sheet, it is difficult to print on the surface, and it is not suitable for use as a packaging container. In addition, if the water resistance is poor, the sheet is sensitive to moisture when the sheets are stored and stored, and the storage conditions are difficult, causing problems during printing, and even after manufacturing the product, the surface is damaged by rain water, which is not suitable for packaging materials.

Although the manufacturing process of the sheet has a difference in thickness, it is almost similar to the manufacturing process of the synthetic resin film, and the situation in which the technology of the manufacturing process of the film is applied and used a lot. The technology currently used in the manufacture of sheets or films is a method of making sheets by mixing and extruding particles directly into the resin constituting the film, forming a coating layer on the surface, and using a device having a specific roll. Manufacturing method;

Korean Patent Application No. 2001-7002342 refers to an aliphatic polyester composition for master batch, which comprises 0.1 to 40 parts by weight of an aliphatic polyester resin and an antiblocking agent. Lactic acid polymers are mainly used as the aliphatic, and titanium dioxide, magnesium carbonate, barium sulfate, magnesium silicate, silica, talc, or kaolin are used as the antiblocking agent. Japanese Patent Application Laid-Open No. 4 (1992) -180957 discloses an antiblocking property by using a resin composition containing polyethylene terephthalate and talc of 10 microns or less as a main component, especially a resin composition containing 0.1 to 1.0% of ultra fine powder. It suggests improvement.

However, they have a disadvantage in that the surface roughness of the film may not be uniform or transparency may be impaired because the antiblocking agent is mixed with the resin component constituting the film and embedded in the film.

Republic of Korea Patent Application No. 1995-000967 relates to a biaxially oriented polyester film for magnetic recording media, manufactured by using a hollow type of silica alone or inorganic addition particles of d90 / d10 is less than 2.00 and 0.1, d50 is less than 4.6 This suggests that a biaxially oriented polyester film can be produced that is excellent in process driving, bi-activity, and wear resistance. However, this invention is not easy to disperse | distribute hollow-type particle | grains, transparency falls, and it is not suitable for manufacture of a packaging sheet.

Republic of Korea Patent Application No. 1986-0010959 dilutes a resin containing fine particles (kaolin, calcium carbonate, silica, titanium dioxide, calcium silicate, alumina, etc.) having a diameter of 5 ~ 1000nm in a mixed solution with methyl ethyl ketone, toluene, etc. Then, by applying a thickness of 0.01 to 5 microns on both sides or the plane of the film, and then drying to form a coating film having a fine projection, by applying a transparent resin dilution containing fine particles on the plane or both sides of the film It has been suggested that by forming the fine projections, it is possible to produce a transparent polyester film having excellent blocking resistance. Korean Patent Application No. 1998-0000023 forms a surface composed of calcium phosphate particles having an average particle diameter of 0.5 to 8 microns, glass beads, and silica particles having an average particle diameter of 0.2 microns or less on an upper surface of a biaxially oriented polyester film, The back side suggests that a biaxially oriented polyester film having excellent coiling properties and transparency can be produced with a coextruded laminated film that does not use particles.

However, when prepared by these methods, there may be sedimentation or aggregation of particles in the coating liquid due to the use of inorganic particles having a specific gravity such as silica or talc, and inorganic particles because the difference in refractive index between the inorganic particles and the resin composition is large. Transparency may be lowered as compared with the state where no is added.

Japanese Patent Application Laid-Open No. 8 (1996) -157619 discloses an ester product of a polyhydric alcohol having three or more hydroxyl groups in a polyester polymer having an intrinsic viscosity of 0.5 to 1.1 and an aliphatic monocarboxylic acid having 12 or more carbon atoms. A polyester sheet blended 0.01 to 5% has a surface protrusion of 1 to 2000 / mm2 of 0.1 to 5 microns in height, and has no damage to transparency, printability and adhesiveness, and improves blocking property. Polyester sheets, molded articles and packaging containers are disclosed.

However, in the case of the present invention, there is a disadvantage in that the water resistance decreases due to the large number of hydroxyl groups on the surface, and also there must be a specific equipment capable of forming fine surface projections on the sheet surface, which can lead to an increase in manufacturing cost.

Korean Patent Application No. 1999-0028756 discloses a water-soluble coating solution containing 0.01 to 5 wt% of modified polyethyleneimine resin as a solid content and 0.01 to 1 wt% of silicon dichloride having a curing agent, a coupling agent, and a particle size of 0.5 micron. To provide a method for producing a direct-extruded polyester film coated with a water-soluble composition having excellent blocking resistance and moisture resistance. Korean Patent Application No. 2001-0042003 describes a method of manufacturing a transfer paper film which is formed by applying a surface slip coating layer on the back surface of a film printing surface to prevent sticking after winding. In particular, the surface slip coating agent consisting of polyester resins, polyurethane resins, waxes, anti blocking agents, moisture inhibitors, solvents, etc. is coated on the surface of the transfer paper film to improve the slip properties.

However, when manufactured by the above methods, the surface tension of the sheet or the film due to the coupling agent or the anti-blocking agent may cause a problem of lowering the surface tension of the printing ink may have a disadvantage in that the printability is lowered Therefore, it is difficult to make products such as cosmetic packaging containers.

Accordingly, the technical problem to be achieved by the present invention is to provide a polyethylene terephthalate sheet having excellent surface slipperiness, transparency, printability, and water resistance.

The polyethylene terephthalate sheet according to the present invention for achieving the above technical problem is characterized in that the surface is coated with a coating solution obtained by stirring the polymer particles into a hydrophobic acrylic emulsion.

It is preferable to obtain the acrylic resin used for manufacture of the said hydrophobic acrylic emulsion using a methacryl monomer. Examples thereof include methyl methacrylate, butyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, hexyl methacrylate and lauryl methacrylate.

Since the said methacryl monomer has the methyl group inherent in a molecular sieve, it is excellent not only in water resistance but also the effect of improving slip property.

It is preferable to further use a vinyl acetate monomer in the preparation of the hydrophobic acrylic emulsion. This is to promote adhesion with the substrate. The vinyl acetate monomer prevents the Tg of the coating layer from becoming too high due to the methacrylic monomer, thereby preventing the adhesion. Therefore, the proper combination of these monomers not only contributes to the water resistance of the polyethylene terephthalate sheet for flat plates, but also helps to improve the surface slip property and adhesion of the coating layer to the substrate.

The polymer particles are preferably spherical particles having an average particle diameter of 0.1 to 20 μm, particularly 0.2 to 10 μm. Such spherical polymer particles are generally called polymer beads, and are prepared by a method such as emulsion polymerization using a thermoplastic or thermosetting resin. do. Such polymer beads include PMMA beads, polystyrene beads, polyester beads, polyurethane beads, and the like according to the composition of the resin to be used.

The above-mentioned polyethylene terephthalate sheet has improved water resistance because it uses a hydrophobic acrylic resin, and because it uses spherical polymer particles having a similar refractive index and a suitable size, such as polyethylene terephthalate resin and acrylic resin, which are substrates, blocking resistance and printability. This is improved. Therefore, it is suitable for use in clear boxes for cosmetic packaging or packaging materials for household goods.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. The following examples are only presented to understand the content of the present invention, and those skilled in the art will be capable of many modifications within the technical spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited to these examples.

EXAMPLE

-Binder synthesis

In order to synthesize the binder to be used for the coating solution, a heating mantle for heating is mounted on a three-necked flask, and a thermometer, a condenser, and an agitator are attached to decorate the synthesis apparatus. 80 g of methyl methacrylate, 45 g of vinyl acetate, 420 g of distilled water, 4 g of sodium dodecylbenzenesulfonate, 1 g of ammonium persulfate, 0.9 g of ammonium acetate, and 7.5 g of hydroxyethyl cellulose were added to the prepared flask, followed by heating.

When the temperature reaches about 67 ° C., the reflux of the reactants begins. After 30 minutes of reflux reaction, 200 g of methyl methacrylate, 95 g of butyl methacrylate, and 100 g of vinyl acetate are mixed well and added over about 2 hours.

After the addition of the reactants, the temperature was raised to 95 ° C., the reaction was carried out for 8 hours, the reaction was completed, cooled to 40 ° C., filtered and packaged. Thus obtained hydrophobic acrylic emulsion had a pH of 5.2, a solid content of 54%, a viscosity of 420 cps, and a particle size of about 0.1 to 0.2 µm.

-Preparation of coating liquid

80g of acrylic resin synthesized in the above method, PMMA polymer beads (Sunjin Chemical, SUNPMMA-S, D50 = 5㎛, refractive index of about 1.57) 1g, dispersant 0.5g (BYK-163, BYK Chemi.GMBH) by adding a high-speed disperser After 1 hour of dispersing, 10 g of butyl cellosolve, 20 g of isopropyl alcohol, 25 g of distilled water, 1.0 g of a surface leveling agent (BYK-300, BYK Chemi.GMBH) were added, stirred and mixed for 1 hour, and then filtered using a 300mesh filter. It is packaged to prepare a surface coating solution.

- coating

Using the coating solution prepared in the above process to form a coating layer 20 on the amorphous polyethylene terephthalate sheet 30 of 0.2mm thickness with a 200mesh gravure roll coater 10 as shown in Figure 1, 30 seconds in a 120 ℃ oven After drying, physical properties were taken out and the physical properties at this time are shown in Table 1. Reference numeral 40 is a polymer bead.

Comparative Example 1

-Preparation of coating liquid

Except for using the polyvinyl alcohol resin instead of the acrylic resin synthesized in the above embodiment is the same as the above embodiment. That is, 80 g of polyvinyl alcohol resin (PVA-207), 1 g of PMMA polymer beads (Sunjin Chemical, SUNPMMA-S, D50 = 5 μm, refractive index of about 1.57), 0.5 g of dispersant (BYK-163, BYK Chemi.GMBH) were added. After dispersing with a high speed disperser for 1 hour, 10 g of butyl cellosolve, 20 g of isopropyl alcohol, 25 g of distilled water, 1.0 g of surface leveling agent (BYK-300, BYK Chemi.GMBH) were added and stirred for 1 hour, followed by mixing and using a 300 mesh filter. Filtered and packaged to prepare a surface coating solution.

- coating

The coating solution prepared in the above process was coated on an amorphous polyethylene terephthalate sheet having a thickness of 0.2 mm using a 200 mesh gravure roll coater, dried for 30 seconds in an oven at 120 ° C., and taken out to evaluate physical properties. It was.

Comparative Example 2

-Preparation of coating liquid

The same procedure as in Example was performed except that talc was used instead of the polymer beads used in the Example. That is, 80 g of acrylic resin, 1 g of talc and 0.5 g of dispersant (BYK-163, BYK Chemi.GMBH) synthesized in the above example were added and dispersed for 1 hour with a high speed disperser, 10 g of butyl cellosolve, 20 g of isopropyl alcohol, and distilled water. 25g, 1.0g of a surface leveling agent (BYK-300, BYK Chemi.GMBH) was added and stirred for 1 hour, and then mixed and filtered using a 300mesh filter to prepare a surface coating solution.

- coating

The coating solution prepared in the above process was coated on an amorphous polyethylene terephthalate sheet having a thickness of 0.2 mm using a 200 mesh gravure roll coater, dried for 30 seconds in an oven at 120 ° C., and taken out to evaluate physical properties. Indicated.

TABLE 1

Evaluation item unit Example Comparative Example 1 Comparative Example 2 Assessment Methods Light transmittance % 87 79 75 Hazemeter [KSMISO 13468-1] Haze % 1.1 2.6 3.5 Hazemeter [KSMISO 13468-1] Anti-blocking Castle - ◎ × △ Sheet lamination Adhesion 100/100 100/100 80/100 75/100 Tape Test [KSM 5981] Surface tension dyne / cm 36 30 30 Accu dyne tester

Here, the anti-blocking test method (sheet lamination method) is a comparative comparison of the force applied when the 10 sheets of 300mm 300300mm size is laminated and pulled in the lateral direction after 1 hour of pressurization at a pressure of 4kg / cm2 at room temperature.

As can be seen in Table 1 above, in the case of Examples compared to Comparative Example 1, the water resistance was improved, thereby improving the blocking resistance, it was found that the adhesion of the coating layer is also improved. In addition, compared with Comparative Example 2, the Example has improved transmittance, lower haze, excellent transparency, and better blocking resistance.

As described above, according to the present invention, since the hydrophobic acrylic resin is used, the water resistance is improved, and since the spherical polymer particles having the similar refractive index and the appropriate size are used, such as the polyethylene terephthalate resin and the acrylic resin as the base material, Printability is improved. Therefore, it does not cause blocking when rolled up or rolled up into a sheet for flat plate, and it is easy to be molded because it is slippery, and also has excellent printability on the surface of the container. It is useful for manufacturing.

Claims (7)

A polyethylene terephthalate sheet, wherein the surface is coated with a coating liquid obtained by injecting and stirring polymer particles into a hydrophobic acrylic emulsion. The polyethylene terephthalate sheet according to claim 1, wherein the hydrophobic acrylic emulsion is obtained using a methacryl monomer. The polyethylene terephthalate sheet according to claim 2, wherein the hydrophobic acrylic emulsion is obtained by further using a vinyl acetate monomer. The polyethylene terephthalate sheet according to claim 1, wherein the polymer particles are made of PMMA, polystyrene, polyester, or polyurethane. The polyethylene terephthalate sheet according to claim 1, wherein the polymer particles have a spherical shape with an average particle diameter of 0.1 to 20 µm. A clear box for cosmetic packaging comprising a polyethylene terephthalate sheet whose surface is coated with a coating liquid obtained by adding and stirring polymer particles into a hydrophobic acrylic emulsion. A packaging material for packaging for household goods, comprising a polyethylene terephthalate sheet whose surface is coated with a coating liquid obtained by adding and stirring polymer particles into a hydrophobic acrylic emulsion.

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