KR0143807B1 - Manufacturing method of polyester film for drawing - Google Patents

Abstract

The present invention relates to a method for producing a polyester film for drafting excellent in matte, pencil writing, printing concrete and transparency, the surface of the transparent film (layer A) having an inorganic particle content of 1.0% by weight or less by coextrusion. Alternatively, a film (B layer) containing a large amount of inorganic particles is laminated on both sides, but the B-crystalline crystalline inorganic particles (C particles) having a Mohs hardness of 5 or more based on the total weight of the B layer are 0.5-10 wt% amorphous porous silica particles. The present invention relates to a method for producing a film, wherein (D particles) is contained in an amount of 0.5 to 8% by weight, and the average particle diameter of the C particles and the D particles also satisfies the following conditions after the B layer.

1 µm ≤ thickness of layer B ≤ 10 µm

2㎛ ≤ average particle size of C particle ≤ 15㎛

3 μm ≤ D particle average particle size ≤ 12 μm

Description

Manufacturing method of polyester film for drawing

The present invention relates to a method for producing a polyester for drawing excellent in matt, pencil writing, printing concrete and transparency, more specifically, the average particle diameter of the polyester and particles having an inorganic particle content of 1.0% by weight or less Coextruded polyester containing 0.5 to 10% by weight of crystalline inorganic particles having a hardness of 2 to 15 μm and a hardness of 5 or more and 0.5 to 8% by weight of amorphous porous silica particles having an average particle diameter of 3 to 12 μm. From a polyester containing at least two layers of laminated films containing amorphous porous silica particles having an average particle diameter of 3 to 12 μm and crystalline inorganic particles having an average particle diameter of 2 to 15 μm and a MOS hardness of 5 or more It relates to a method for producing a polyester film for drafting, characterized in that the thickness of the layer to be produced (hereinafter referred to as layer B) is 1 to 10 µm.

Today's industrially manufactured polyesters, especially polyethylene terephthalate (hereinafter PET), have outstanding physical and chemical properties, making them suitable for use in medical, industrial textile and magnetic tapes, capacitors, packaging, photographic films, as well as molding. It is widely used for the purpose of processed goods.

However, polyester films, in particular biaxially stretched polyester films, have a variety of properties such as low gloss, contrast of printing, writing by pencil, and rapid copying due to their inherent transparency and high gloss. It was difficult to apply to. In order to solve this problem of a biaxially stretched polyester film, various methods have been proposed. That is, in the conventional method for producing a polyester film for drafting, the inorganic particles having high hardness such as chemical etching, silica sand, etc. which are roughened by etching one or both surfaces of a normal transparent polyester film with alkali, acid, etc. The finished polyester film is once again processed, such as a sand blast method that impinges a polyester film and roughens the film, and a coating method in which an opaque coating solution containing inorganic particles such as silica and CaCO3 is applied onto the polyester film. The direct-matte method which adds the inorganic particle which forms an appropriate uneven | corrugated structure during the post-processing method and the resin manufacturing process for polyester films, and the method of combining these suitably are proposed.

For example, Japanese Patent Application Laid-Open No. 48-79227 describes an internal particle addition method for forming particles of polyester into resin using a metal compound, a catalyst, and the like used in the production of a polyester resin. -32971, Japanese Patent Application Laid-Open No. 54-148832, Japanese Patent Application Laid-Open No. 4-117431, British Patent No. 877541, U.S. Patent No. 31,441,1, U.S. Patent No. 3,302,206, and the like. External particle addition methods for adding inert inorganic particles such as molybdenum oxide and silicon oxide to the reaction system are known. Japanese Patent Publication Nos. 51-41771 and 63-89546 disclose polystyrene, polyarylate, and phenoxy. A method of adding a heat resistant organic resin is described, and US Patent No. 1465973 describes a method of embossing a surface having a low melting temperature by laminating polymers having different melting temperatures. Patent No. 2012617 discloses a method of adding crystalline silica to a polyester resin by a direct matt method to impart writing properties and applying a matte coating liquid during the film manufacturing process, and Japanese Patent Laid-Open No. 55-50036 Silica is added to the polyester resin by a direct matt method to impart matte properties, and then a method of imparting peeliness by sandblasting post-processing is mentioned, and Japanese Patent Application Laid-Open No. 63-89546 and Japanese Patent Publication No. 4-110148 A method of laminating a matte layer and a transparent layer for the purpose of reinforcing physical properties is described.

However, the matte polyester film produced by the particle addition method usually has a gloss of 20% or more, so that a sufficient matte effect that effectively prevents the blinding of the eye is difficult to achieve. When scratched on the outermost surface layer of the film there was a problem that the marks remain even after erasing. In addition, a method of adding heat-resistant organic particles and a method of embossing a surface having a low melting temperature by stacking polymers having different melting temperatures can sufficiently prevent glare, but scratch and erase of scratches shown by a high hardness pencil are prevented. Later generation problems could not be prevented. In addition, the method of adding crystalline silica and applying the matte coating liquid greatly improved the economics by omitting the post-processing process, but the viscosity of the coating liquid was high because the inorganic liquid for expressing the matte effect should be contained in the coating liquid There was a problem that the product was deteriorated due to a large rise caused by the heterogeneity of the coating.

On the other hand, the method of adding amorphous silica and sandblast post-processing can satisfy the physical properties required for the drafting film, but once the finished film is processed again, there is a problem that is not economical. In addition, the method of laminating two or more layers can simultaneously achieve mutually opposite physical properties, for example, mechanical strength and matte properties, which are difficult to satisfy at the same time by appropriately blending additives contained in each layer. It is economically preferable because it can omit the post-processing process, but it can satisfy various special requirements such as low gloss, pencil writing, contrast of printing, and transparency for quick copying. It was impossible.

Accordingly, an object of the present invention is to provide a polyester film for drafting which can satisfy all of the required properties of the film for drawing, such as matteness, pencil writing, printing contrast and transparency in the manufacturing process of the film without undergoing a post-processing process. It is to provide a manufacturing method.

As a result of earnestly examining in order to achieve not only the above object but also another object that can be easily expressed, crystalline inorganic particles having high MOS hardness and amorphous porous silica particles having excellent matte effect are properly dispersed and mixed in one or both outermost layers. The present invention was completed by discovering that all required properties of the drafting film can be provided in the film manufacturing process.

The present invention is described in more detail as follows.

Drafting polyester film of the present invention by laminating a film (B layer) containing a large amount of inorganic particles on one side or both sides of the transparent film (A layer) having an inorganic particle content of 1.0% by weight or less by co-extrusion, Regarding the total weight of the layer, 0.5 to 10% by weight of crystalline inorganic particles (C particles) having a MOS hardness of 5 or more and 0.5 to 8% by weight of amorphous porous silica particles (D particles) are contained. It is manufactured by making the average particle diameter of C particle | grains and D particle | grains satisfy | fill the following conditions.

1 µm ≤ thickness of layer B ≤ 10 µm

2㎛ ≤ average particle size of C particle ≤ 15㎛

3 μm ≤ D particle average particle size ≤ 12 μm

The polyester used in the present invention is prepared by polycondensation of a low polymer obtained by transesterification or ester reaction of a dicarboxylic acid having a terephthalic acid or an ester derivative thereof and a glycol having a ethylene glycol as a main component using a known polymerization catalyst. It may be a homopolyester or a copolyester, and as a component to copolymerize, for example, diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, paraxylene glycol, 1.4-cyclohexanemethanol, bisphenol A, etc. This can be used.

However, it is effective that the melting point of the polyester to be used is at least 200 ° C, preferably at least 20 ° C, and at least 80% of the repeating structural units have ethylene isophthalate units. In addition, the polymerization catalyst used in the present invention includes compounds such as antimony, titanium or germanium soluble in glycol, specifically, antimony trioxide, tetraalkyl titanate, and the like, and, if necessary, lubricants, heat stabilizers, antioxidants, A colorant, a ultraviolet absorber, an antistatic agent, etc. can be contained separately.

Moreover, it does not matter even if it adds and mixes polymers other than polyester, such as polystyrene, polyamide, polypropylene, polycarbonate, etc. to 20 weight% or less with respect to the said polyester.

In addition, it is effective that the ultimate viscosity of the polyester used for A-layer is 0.55 or more, Preferably it is 0.60 or more. If the intrinsic viscosity of the polyester used in the layer A is less than 0.55, it is not preferable because a film having sufficient mechanical strength cannot be produced. In addition, it is effective that the intrinsic viscosity of the polyester used in the B layer is 0.40 or more, preferably 0.45 or more, and when the intrinsic viscosity is 0.40, the molding is difficult and the productivity is low.

The polyester raw material used for the layer B may contain an appropriate amount of crystalline inorganic particles having a hardness of 5 or more and amorphous porous silica at the same time. Alternatively, raw materials containing the respective particles may be separately prepared and dried before the film is manufactured. Blending may be appropriate at.

Crystalline inorganic particles having a Mohs hardness of 5 or more used in the present invention are crystal patterns by X-RAY such as alumina, silica, titanium oxide, anhydrous kaolin, zirconia, feldspar, silicon, carbide, etc. it means. Among these, silica that is transparent when added to polyester, has less deterioration of color tone and yellowing, and has less degradability to polyester, may be preferably used. In particular, among the crystalline silica, diatomaceous silica is less abrasion to the machinery required for the production of polyester film, such as extruder barrels, rolls, rolls, edge trimming knives, etc., compared to quartz. It can be used preferably.

When the morphological inorganic particle used in the present invention is less than 5, it is difficult to make a clear drawing, and there is a problem in that the drawing is incorrect and pencil marks remain after erasing with an eraser when correcting. The amorphous porous silica particles used in the present invention are amorphous particles in which a crystal pattern does not appear by X-RAY and sponges containing a large amount of pores in a secondary aggregate formed of a three-dimensional network structure of primary particles. Refers to silica particles of similar structure. Since such particles are present in a large amount of voids, the particles are excellent in the ability to deform the form when friction with the object, that is, excellent in deformability, and thus does not wear the machinery required for film production. In addition, since a large amount of voids exists, the number of particles per unit weight is greater than that of particles without voids, and therefore, even with a small amount of addition, an excellent matt effect can be achieved.

As for the average particle diameter of the crystalline particle used for this invention, 2 micrometers-15 micrometers are preferable, and 2.5 micrometers-12 micrometers are especially effective. If the average particle diameter is less than 2㎛, writeability by pencil is insufficient, and if it exceeds 15㎛, the pressure increase of the filter proceeds rapidly and the filter replacement must be frequently performed. The size of the surface projections caused by the particles is too large, there is a disadvantage that the sharp drafting is difficult.

The amount of the crystalline particles added is preferably 0.5 to 10% by weight, preferably 1 to 8% by weight based on the total weight of the B layer. If less than 0.5% by weight, there is a problem that the pencil writing ability is insufficient, if it exceeds 10% by weight there is a problem that wear the machinery necessary for film production is not preferable. If the average particle diameter of the amorphous porous silica particles exceeds 3 to 12 µm, there is a problem in that the pressure increase is remarkable and productivity is lowered. The amount of the amorphous porous silica particles added is 0.5 to 8% by weight, preferably 1 to 6% by weight based on the total weight of the B layer. If the added amount is less than 0.5% by weight, the matte effect is insufficient, and if it is more than 8% by weight, the light transmittance is poor. As a conventional single-layer film, it is impossible to simultaneously provide transparency for rapidness of replication and properties for making the film opaque, such as matte, contrast of printing, and handwriting, so that the film of the present invention is at least two or more layers by coextrusion. It is necessary to be stacked. The thickness of the B layer containing the crystalline inorganic particles and the porous silica particles is preferably in the range of 1 to 10 µm, and when the thickness of the B layer is less than 1 µm, molding is difficult, and the B layer is uneven and the appearance is poor. There is a problem that is not beautiful, when it exceeds 10㎛ has a disadvantage in that the transparency is reduced and the replication speed is slowed. Although the thickness of the film of this invention is not specifically limited, 25-200 micrometers is suitable like a general drafting film, and 38-175 micrometers is more preferable. The film of the present invention is not limited to the use as a drawing film, and can be applied to applications such as display panels, optical diffusers, labels, stamping foils, and the like without departing from the gist thereof.

In the film of the present invention, a polyester containing an appropriate amount of crystalline inorganic particles and amorphous porous silica particles and a polyester containing no inorganic particles are separately used using a dryer or a vacuum dryer commonly used such as a hopper dryer or a paddle dryer. After drying, melt extrusion at 250-300 ° C. with a separate extruder, and by co-extrusion, the layer composed of the raw material containing the inorganic particles is compounded so as to be the outermost layer on at least one side and casting drum It is prepared by cooling the solid to form an amorphous sheet composed of two or more layers. At this time, the use of the usual electrostatic application method is preferable because the nonuniformity of the amorphous sheet is improved and the cooling effect is good. Although the drawing conditions of a film are not specifically limited, It is effective that draw ratio is 2.0 times or more in a longitudinal direction, 3.0 times or more in a horizontal direction, and extending | stretching temperature is 70 degreeC-160 degreeC, and when heat processing is needed, 160 degreeC-240 degreeC desirable. In the heat treatment step, it is preferable to perform relaxation at 1 ° C. to 10% in the transverse direction at the maximum temperature and / or cooling zone of the heat treatment. In the heat treatment step, the two-stage heat treatment may be performed.

In order to impart adhesiveness, antistatic property, mold release property, UV blocking property, etc. to the film during or after the stretching process, a coating layer may be formed on one or both surfaces of the film, or a corona discharge treatment may be performed. In addition, the coating layer formed during or after the stretching process may have two or more kinds of functions, for example, adhesiveness and UV blocking properties, or may be two or more multilayer coating layers.

The following examples and comparative examples to illustrate the present invention in more detail, but do not limit the scope of the present invention, each of the physical properties and properties were measured by the following method.

1.light transmittance

It measured by ASTMD 1003 and determined that it was 50% or more.

2. Glossiness

A value measured at 60 ° using BYD GARDNER's MICRO-TRI-GLOSS according to ASTM D 523, and was determined to be very good at 10% or less, good at 10 to 20%, and poor at 20% or more.

3. pencil handwriting

Using a pencil of different sharpness B to 5H with the same degree, the line was drawn under the same pressure and then erased with an eraser to determine the degree of scratches generated in the film layer. When a scratch generate | occur | produced, it judged that it was defective and when it did not generate | occur | produce.

4. Smear hardness

After drawing the lines with pencils for each hardness, rub the lines five times with a paper tissue containing a little bit of water, and then determine the degree of spreading and mark the best pencil hardness without spreading the lines. HB or less was very good, 1H was good, and 2H or more was determined to be bad.

5. Contrast of printing

It was determined by the light transmittance and was determined to be poor when exceeding 70%, good when 60 to 70%, and very good when less than 60%.

6. Backward film

It was measured from the photograph of the film cross section.

7. Average particle diameter

It means the equivalent spherical diameter of the particle at 50 weight% of all the measured particles.

The equivalent spherical diameter means the diameter of a sphere having the same volume as the particles, and can also be obtained by an electron micrograph of the particles or by a conventional sedimentation method.

Example 1

Polyethylene terephthalate (A1) containing 10% by weight of crystalline silica particles having an average particle diameter of 6 µm, polyethylene terephthalate (A2) containing 10% by weight of amorphous porous silica particles having an average particle diameter of 4 µm, and inorganic particles Polyethylene terephthalate (C), which was not blended in a ratio of 33:25:42 by weight ratio (A1: A2: B) by weight ratio, was used as a raw material. The raw material C and the raw material B were dried separately by a known method, and then, a separate extruder was used to make the raw material C and the raw material B into three layers of a thick film C / B / C-6 / 88/6 to prepare an amorphous sheet. . The sheet was stretched 3.8 times in a temperature range of 70 to 130 ° C. in the longitudinal direction, and then stretched 4.0 times in a temperature range of 90 to 145 ° C. in the transverse direction, followed by heat setting at 235 ° C. to obtain a film having an average thickness of 50 μm. .

Example 2

Instead of the raw material B of Example 1, the polyethylene terephthalate containing 0.15 weight% of silica particles with an average particle diameter of 2.3 micrometers was used as the raw material B. The raw material B was dried separately by the well-known method, respectively, and the raw material C was structured two layers of the raw material C and the raw material B with thick ratio C / B = 10/90 by the separate extruder, and the amorphous sheet was produced. This sheet was produced in the same manner as in Example 1 to obtain a film having an average thickness of 50 μm.

Comparative Example 1

The polyethylene terephthalate which blended the raw material A1 and the raw material B of Example 1 by 50:50 ratio by weight ratio was used as the raw material (C).

The raw material C and the raw material B were three-layer structured with thick ratio C / B / C = 6/88/6, and the amorphous sheet was produced. This sheet was produced in the same manner as in Example 1 to obtain a film having an average thickness of 50 μm.

Comparative Example 2

Polyethylene terephthalate obtained by blending the raw material A 2 and the raw material B of Example 1 in a weight ratio of 45:55 was used as the raw material (C).

After the raw material C and the raw material B were dried separately by a well-known method, the raw material C and the raw material B were three-layer structured with thick ratio 6/88/6 by the separate extruder, and the amorphous sheet was produced. This sheet was produced in the same manner as in Example 1 to obtain a film having an average thickness of 50 μm.

Comparative Example 3

The raw material C of Example 1 was dried by a known method alone, and then an amorphous sheet was produced by an extruder. This sheet was produced in the same manner as in Example 1 to obtain a film having an average thickness of 50 μm.

The result of having judged the characteristic of the film obtained by the said Example and the comparative example was described in the table.

Claims (1)

By co-extrusion, a film (B layer) containing a large amount of inorganic particles is laminated on one or both sides of the transparent film (A layer) having an inorganic particle content of 1.0% by weight or less, and the B hardness is 5 against the total weight of the B layer on the B layer. The above-mentioned crystalline inorganic particles (C particles) are contained in an amount of 01.5 to 8% by weight of 0.5 to 10% by weight amorphous porous silica particles (D particles). Method of producing a film, characterized in that to satisfy. 1 µm ≤ thickness of layer B ≤ 10 µm 2㎛ ≤ average particle size of C particle ≤ 15㎛ 3 μm ≤ D particle average particle size ≤ 12 μm