KR101339938B1 - Opaque White film - Google Patents

Abstract

The present invention relates to a white film, specifically, a polyester resin and particles having an average particle diameter of 1.0 to 1.5 µm by a circular diameter, and having no particle having a particle diameter of 0.0001-0.3 µm or less than 5% by volume and a particle diameter of 3.0. It has a particle size distribution with no particles of -10.0㎛ or less than 5% by volume, and has excellent concealability and whiteness, including barium sulfate having a long diameter / short diameter ratio of 0.7 to 1.0 and a refractive index of 1.6 to 1.7. In addition, there is no breakage of the film by minimizing the generation of voids during film production, and relates to a white film having good operability.

White Film, Barium Sulfate, Circular Diameter, Polyester

Description

White film {Opaque White film}

The present invention relates to a white film, and more particularly to a white film excellent in opacity for advertising billboards, placards, labels, packaging for food or beverages.

Currently, paper, a white plastic film, and the like are generally used as substrates for labels, flyers, cards, calendars, and the like, and polyvinyl chloride, polyolefin, polystyrene, and the like are used as plastics.

In general, polyolefin films containing inorganic fine particles have been used as substrates for paper substitutes. However, polyolefin films have limited mechanical strength, heat resistance, weather resistance, and numerical stability. It is a tendency to use as a paper substitute of a use.

Polyester is widely used in the manufacture of medical and various industrial products due to its physical and chemical stability, high mechanical strength, excellent heat resistance, durability, chemical resistance, and electrical insulation. Among them, polyethylene terephthalate has excellent properties such as elastic modulus, dimensional stability, flattening, and so on, such as magnetic recording media, capacitors, food or beverage packaging, photographic films, labels, and various graphic arts products. It is used widely. In addition, it is used for various magnetic cards (credit and communication cards), printer award papers, bar codes, posters, calendars, maps, dust-free papers, display boards, white boards, photo papers, copy papers and special printed publications.

Recently, as a method for controlling the high transparency of a polyester film having such high transparency and surface glossiness to use the film for various purposes, a method of adding white inorganic particles having a high refractive index has been studied. For example, in Korean Patent Laid-Open Publication No. 2000-0061237, inorganic particles such as calcium carbonate were added to polyester, but the amount of calcium carbonate added to control the amount of calcium carbonate caused by excessively high glossiness of the film surface causes eye fatigue. Increasing the film stiffened the workability was poor. Accordingly, Korean Patent Invention No. 773705 proposes a white film having low transparency by adding barium sulfate to polyester alone, but it is difficult to manufacture a white film having uniform physical properties because the particle size distribution of barium sulfate particles is not controlled. In addition, there is a risk of breakage occurring during stretching.

In addition, when the film is prepared by adding a large amount of the inorganic particles, the specific gravity of the polyester is increased, so that the weight of the film is not easily reduced. When the film is prepared by mixing the blowing agent, the dispersibility of bubbles is poor and the inorganic material to be added is Difficult to control the particle size, it is difficult to control the physical properties of the film.

In addition, the effect of improving the concealability and whiteness is not remarkably improved through the addition of the inorganic substance, the amount of pores formed in the film by the added inorganic substance is excessive, the strength is lowered, and the film breakage frequently occurs during the film forming process. There is a problem that occurs.

In order to solve the above problems, an object of the present invention is to provide a white film having excellent concealability and whiteness, minimizing the occurrence of voids during film production, no breakage of the film, and good operability.

In order to achieve the above object, the present invention has a polyester resin and particles having an average particle size of 1.0 to 1.5 μm, and a particle size of 0.0001-0.3 μm, or no distribution of 5% by volume or less, and a particle size of 3.0-. Provided is a white film containing barium sulfate having a particle size distribution having no particles of 10.0 μm or having a particle size distribution of 5 volume% or less, having a long diameter / short diameter of 0.7-1.0, and a refractive index of 1.6-1.7.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

The terms "about "," substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation of, or approximation to, the numerical values of manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The present invention is a polyester resin, the average particle size 1.0 ~ 1.5㎛ by the circular diameter, no particles having a particle diameter of 0.0001-0.3㎛, or less than 5% (Volume), particle size is 3.0-10.0㎛ or no 5 volume Provided is a white film containing barium sulfate having a particle size distribution of less than (Volume)%, having a long diameter / short diameter of 0.7-1.0, and a refractive index of 1.6-1.7.

The polyester resin used for the white film according to the present invention preferably has an intrinsic viscosity of 0.60 to 0.70. When the intrinsic viscosity of the polyester resin depends on the processability and the physical properties of the film, when the intrinsic viscosity is less than 0.60, the strength of the film at the time of processing can not be increased enough to satisfy the breakage at the time of stretching, productivity is lowered, exceeds 0.70, The melt viscosity is very high, and productivity in the post process is greatly reduced due to difficulties in the film forming process such as an increase in extrusion pressure.

The polyester resin used in the white film according to the present invention is not particularly limited, but it is preferable to use polyethylene terephthalate (PET) in consideration of the thermal stability and physical properties of the film.

The PET is obtained by condensation polymerization of an acid component containing dicarboxylic acid as a main component and a glycol component containing alkyl glycol as a main component. Terephthalic acid or its alkyl ester or phenyl ester is mainly used as the dicarboxylic acid, but a part thereof is transferred, such as isophthalic acid, oxyethoxy benzoic acid, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, and the like. It can be used in place of a functional carboxylic acid or its esterifying derivative.

As the glycol component, ethylene glycol is the main object, but a part thereof is propylene glycol, trimethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-bisoxyethoxy It can also be used by replacing it with benzene, bisphenol, and polyoxyethylene glycol, and if it is a small content, you may use together a monofunctional compound or a trifunctional compound.

The barium sulfate contained in the white film of the present invention is used to enhance whiteness and opacity (hiding force), and the pores are formed by the barium sulfate, which is an inorganic material of the present invention, and these pores absorb light of a specific wavelength. Without spreading light uniformly, the film is sufficiently bleached to improve whiteness. The shape, average particle size, or particle size distribution of barium sulfate affects whiteness, gloss, opacity, and operational stability.

The average particle diameter of the barium sulfate is 1.0-1.5 μm, and there are no particles having a particle size of 0.0001-0.3 μm or less than 5% by volume, and no particles having a particle size of 3.0-10.0 μm or 5% by volume. It is preferable to have a particle size distribution which is below, and it is more preferable that 95-100 volume% of a particle size distribution is 0.3-3 micrometers.

In general, in the distribution of particle diameters in the particle group constituting the granules, the granules are composed of particles of irregular shape and uneven size, and Heywood's in representing the particle diameter of such irregularly shaped particles. diameter). Here, the circular diameter means the diameter of a circle having the same width as the projection width of the particle.

If the average particle diameter of the barium sulfate is less than 1.0 μm, fine barium sulfate particles may aggregate to form aggregates, and thus the dispersibility of the particles may not be improved, and concealability may not be improved. If the particle size is too large, the pore size increases when the film is stretched, resulting in poor operation and deterioration of whiteness and opacity.

Further, when the distribution of particles having a particle size of 0.0001-0.3 μm by the circular diameter exceeds 5 volume% and the distribution of particles having a particle size of 3.0-10.0 μm exceeds 5 volume%, that is, If the particle size distribution becomes larger than a certain range of particles, the size of the particles becomes non-uniform, the size and frequency of the pores when stretching to the film is also uneven, which may cause a malfunction of the film breakage, and uniform physical properties of the final film It becomes difficult to get

The distribution of particles having a diameter of 0.0001-0.3 μm is better to include all of those having a particle diameter of 0.3 μm or less, and the distribution of particles having a density of 3.0-10.0 μm includes all of those having a size of 3.0 μm or more, but most of the particles in the above range Achieve.

In addition, it is preferable to include the particle size distribution of 0.0001-0.3 μm and 0.001-5% by volume of particles having a particle size of 0.0001-0.3 μm by the circular diameter, and more preferably, the particle distribution in the above range. There is no particle | grains which have.

On the other hand, the ratio of the long diameter / short diameter of the barium sulfate contained in the white film of the present invention may be 0.7 to 1.0, the refractive index may be 1.6 to 1.7. The long diameter / short diameter ratio of the above range is preferably in the form of the barium sulfate of the present invention is close to the sphere, it may contribute to the formation of uniform and minimal pores and to improve the workability and the improvement of physical properties and whiteness of the final film. In addition, if the refractive index is less than 1.6, the glossiness is out of the required level, and if it exceeds 1.7, there is a fear that the absorbed light is increased to decrease the required whiteness.

Therefore, by adjusting the average particle size or particle size distribution, shape and refractive index of barium sulfate as described above, the size of the pores is uniform and minimized, there is no breakage during film stretching, white film having satisfactory whiteness, opacity and gloss Can be obtained.

In the white film of the present invention, the barium sulfate may be included in 3 to 60 parts by weight with respect to 100 parts by weight of the polyester resin, more preferably contained in 10 to 30 parts by weight. When the barium sulfate is less than 3 parts by weight, the whiteness or concealability of the film cannot be imparted, and when the barium sulfate is more than 60 parts by weight, breakage occurs during stretching.

The white film according to the present invention has a thickness of 10 to 500 µm, and provides a white film having an opacity of 95 to 99% and a glossiness of 50 to 65. If the thickness of the film is less than 10㎛, there is a possibility that the opacity is low and the physical properties are lowered, the difficulty of manufacturing 500㎛ and suitable applications can be limited.

The white film of the present invention is preferably opacity of 95 to 99%, glossiness of 50 to 65, it can exhibit the optimum effect when applied to a suitable use.

The white film according to the present invention may be prepared by directly including barium sulfate together with a polyester resin during extrusion, but is more preferably applied in the form of a masterbatch containing barium sulfate in the polyester resin. In addition, it can be produced by biaxial stretching through the extrusion of the masterbatch and the polyester resin.

In addition, the white film of the present invention can be used for interior decoration, architectural exhibitions, exhibition necessities, displays, placards or labels, in facilities outside a store or shop, as advertising necessities or laminates, or in food or beverage packaging materials. Suitable for the application of the furnace, in particular can be preferably used for label and card printing.

As described above, the white film of the present invention does not cause breakage during the manufacturing process by using an inorganic material in a controlled form, and has excellent gloss, whiteness, and opacity.

Through the following examples will be described in more detail.

Example 1

1) Preparation of Masterbatch

100 parts by weight of polyethylene terephthalate having Intrinsic Viscosity = 0.65, particle size of 1.0 µm by the original diameter, particle size of 0.0001-0.3 µm, 3% by volume, and particle size of 3.0-10.0 A compounding chip was prepared by quantitatively introducing 100 parts by weight of barium sulfate having a volume distribution of 2 μm, a long diameter / short diameter of 0.9, and a refractive index of 1.64 in a twin screw extruder hopper.

2) white film production

36 wt% of the master batch chip prepared above and polyethylene terephthalate chip having an intrinsic viscosity of 0.65 without particles added in the polymerization step were transferred to a dryer at 64 wt% and dried at 160 ° C. for 8 hours to mix two kinds of chips. At this time, the dried chip was lowered to a level of 100 ppm or less. As described above, the masterbatch chip and polyethylene terephthalate chip from which moisture was removed were put into an extruder, melted, extruded from a T-die, and a sheet having a surface temperature of 30 ° C. was prepared.

The prepared polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 105 ° C., then cooled to room temperature, and then preheated at 130 ° C. above the machine direction (MD) stretching temperature, followed by the width direction (TD). Axially stretched by 3.8 times and heat-treated at 220 ° C. in a heat treatment zone of at least five stages of tenter. Then, the film was relaxed at 210 ° C. and 5% with respect to the length in the width direction, and then cooled. Prepared.

Example 2

The distribution of particles having an average particle diameter of 1.5 μm and the particle size of 0.0001-0.3 μm by the circular diameter is 3% by volume, and the distribution of particles having a particle size of 3.0-10.0 μm is 2% by volume. It carried out similarly to Example 1 except having used the barium sulfate whose ratio is 0.8 and the refractive index is 1.64.

Comparative Example 1

Using a barium sulfate having an average particle diameter of 1.5 μm, a particle size of 0.0001-0.3 μm, a volume distribution of 3% by volume, and a particle size of 3.0-10.0 μm, a volume distribution of 10% by volume. Except that, it was carried out in the same manner as in Example 1.

Comparative Example 2

By using a barium sulfate having an average particle diameter of 1.0 μm, a particle size of 0.0001-0.3 μm, a volume distribution of 10% by volume, and a particle size of 3.0-10.0 μm, a volume distribution of 2% by volume. Except that, it was carried out in the same manner as in Example 1.

*Test Methods

1) Measurement of intrinsic viscosity

It was measured at a concentration of 0.3 g per 25 ml of ortho-chloropetol at 35 ° C.

2) Measurement of Average Particle Size and Particle Size Distribution by Circular End Diameter

The average particle size and particle size distribution of the particles dispersed in ethylene glycol were measured using a Beckman particle size analyzer Laser Diffraction Particle Size Analyzer (LS 13 320).

3) Measurement of long diameter / short diameter

The long and short diameters of the particles were measured in units of (0.1 μm) through a scale with a photograph of the particles using a scanning electron microscope (SEM).

4) Measurement of fracture

During the stretching of the prepared film or during the heat treatment, the film was broken in the process section, and it was visually confirmed to see a state in which normal operation was impossible.

5) Measurement of opacity

Measurement was performed using a Film Opacity Meter Series 6000 instrument.

6) Measurement of glossiness

Using a gloss meter (Model 4011) of Labotron, Germany, was measured according to the ASTM D523 method based on the black diameter at the measurement angle of 60 ㅀ.

7) Scanning electron microscope (SEM) measurement

Scanning electron microscope (SEM) Using a Jeol JSN 6700F instrument was observed at a magnification of 1000 ~ 5000 times.

[Table 1]

division
Conditions of Barium Sulfate Film properties Average particle size by cloud diameter Long diameter / short diameter Particle size 0.0001-0.3㎛
Distribution Particle size distribution Fracture Opacity
(Opacity) Polish
(Gloss) Problem unit ㎛ - volume% volume% - % % - Example 1 1..0 0.9 3 2 none 98 64 Good Example 2 1.5 0.8 3 2 none 96 56 Good Comparative Example 1 1.5 - 3 10 Occur 98 42 Poor operation / lack of gloss Comparative Example 2 1.0 - 10 2 none 87 65 Lack of opacity

1 is a SEM picture of a white film prepared according to Example 1 of the present invention, Figure 2 is a SEM picture of a white film prepared according to Comparative Example 1. Referring to FIG. 1 and FIG. 2, it can be seen that the pores of the film of FIG. 1 are uniform and smaller.

As a result of Table 1 and Figure 1, in the case of Examples 1 and 2, a white film was produced in the fairness and satisfactory in terms of physical properties without breaking, but in the case of Comparative Example 1 barium sulfate particle size 0.0001-0.3㎛ Phosphorus particles have a volume distribution of 10% by volume, and as shown in the film form of FIG. 1, due to the nonuniformity and large pore size, breakage occurs during stretching, poor operation, and less than the required level of gloss. Indicated. In addition, in the case of Comparative Example 2, the distribution of particles having a particle size of 3.0-10.0 μm of barium sulfate appeared to be less than the required level of opacity at 10% by volume.

The present invention described above is not limited to the above-described embodiments, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be obvious to him.

1 is a SEM photograph of a white film prepared according to Example 1 of the present invention.

Figure 2 is a SEM photograph of a white film prepared according to Comparative Example 1.

Claims (5)

With respect to 100 weight part of polyester resins, the average particle diameter 1.0-1.5 micrometers by the circular diameter, 0.001--5 micrometers of particle | grains whose particle diameters are 0.0001-0.3 micrometers, and 0.001-5 volume of particles whose particle diameters are 3.0 micrometers-10.0 micrometers It contains 10 to 60 parts by weight of barium sulfate having a particle size distribution of%, a long diameter / short diameter ratio of 0.7 to 1.0, a refractive index of 1.6 to 1.7, and a thickness of 10 to 500 µm and an opacity of 95 to 99%. , White film having a glossiness of 50 to 65%. delete The method of claim 1, The polyester resin is a white film having an intrinsic viscosity of 0.60 ~ 0.70. The method of claim 3, The polyester resin is a polyethylene terephthalate white film. delete

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