JP2566607B2 - Tracing film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tracing film having excellent writability, and more particularly to a tracing film having solvent resistance.

(Problems to be Solved by Conventional Techniques and Inventions) Tracing films are widely used for general drafting, for original drawings of shipbuilding, bridge steel frames, etc.

As the base material for the tracing film, a polyester film having excellent dimensional stability, transparency, flatness, resistance to moist heat and various mechanical properties is used, and the surface is roughened to give writing property. ing. Also known is a tracing film in which a coating film in which fine particles are mixed with homopolymer of methyl methacrylate or polyurethane is provided on the surface of the base film.

However, the conventional tracing film has insufficient solvent resistance to the solvent (water, alcohol, thinner, etc.) used for correction. In addition, abrasion resistance and receptivity to various writing means (ballpoint pen, water-based ink, etc.) are not sufficient.

(Means for Solving Problems) As a result of intensive investigations by the present inventors in view of the above problems,
The inventors have found that a polyester film having a specific coating layer is suitable as a tracing film, and completed the present invention.

That is, the gist of the present invention is to have a coating layer containing a graft copolymer resin having an acrylic polymer as a trunk chain and an acrylic polymer having a hydroxyl group as a branch chain on one surface of a polyester film, Roughness (Ra) is 0.
The tracing film is characterized by having a thickness of 2 to 1.0 μm.

 Hereinafter, the present invention will be described in detail.

The polyester of the polyester film in the present invention is polyethylene terephthalate in which 80 mol% or more of its constituent units are ethylene terephthalate or polyethylene naphthalate in which ethylene naphthalate is used.

The polyester film of the present invention, if necessary, inorganic particles, organic particles, organic lubricants, antistatic agents, stabilizers,
The composition may contain a dye, a pigment and an organic polymer. In order to impart slipperiness to the polyester film, fine particles are contained in the film composition, but the type, size, and amount of the protrusion-forming agent are selected according to the required properties such as slipperiness and transparency as a tracing film. Is appropriate
Selected.

The thickness of the polyester film of the present invention is 25 to 250 μm
Is preferable, and more preferably 50 to 200 μm. When the thickness of the polyester film is less than 25 μm, the tracing film has a poor rigidity and is inferior in handleability.

The tracing film of the present invention is provided with a coating layer on one surface of such a polyester film, and the coating layer contains a graft copolymer having an acrylic polymer as a trunk chain and an acrylic polymer having a hydroxyl group as a branch chain. It is necessary.

The acrylic polymer that forms the backbone of the graft copolymer includes (i) acrylic acid, methacrylic acid, metal salts and ammonium salts of these acids, anhydrides of these acids, and halides of these acids, (ii) ) Polymers or copolymers having acrylic acid or methacrylic acid ester, (iii) acrylonitrile and methacrylonitrile, (iv) acrylamide, methacrylamide, and N-substituted derivatives of these amides as components. Of these polymers, hydrophobic ones are preferable, and examples thereof include, but are not limited to, polyalkyl acrylate and polyalkyl methacrylate. Depending on the grafting efficiency, some hydrophilic groups may be introduced into the main chain. May be.

On the other hand, the acrylic polymer having a hydroxyl group serving as a branch is a polymer in which a substituent having a hydroxyl group is introduced into the above-mentioned acrylic polymer, and it is a hydroxyalkyl polyacrylate, hydroxyalkyl polymethacrylate, polyN. -Alkyrol acrylamide, poly N-alkylol methacrylamide and the like are mentioned as preferred examples, but the present invention is not limited thereto.

The composition ratio of the graft copolymer composed of such constituent components is preferably in the range of 60 to 90 wt% for the trunk chain component and 10 to 40 wt% for the branched chain component. For example, (1) chain transfer method ( 2) Polymer initiator method (3) It can be produced by a known method such as a radiation graft method. Usually, the copolymer obtained by these production methods can be directly used as a coating agent without isolation.

Examples of commercially available graft copolymers satisfying the requirements of the present invention include L-20 (trade name) and L-40 manufactured by Soken Chemical Industry Co., Ltd.
(Product name), etc., but not limited to these.

Further, in the coating layer of the film of the present invention, other resin, fine particles, if necessary, in addition to the above-described graft copolymer.
It may contain a coatability improver, a dye, a pigment, etc.,
Usually, in order to improve the writability, fine particles are blended in the coating layer, or a white pigment is blended in the coating layer so that the written line image becomes clear. Inorganic particles such as silica, kaolin and calcium carbonate, or organic particles are used as the fine particles, and titania is used as the white pigment. In the tracing film of the present invention, it is necessary that the surface roughness (Ra) of the coating layer is in the range of 0.2 to 1.0 μm. When the surface roughness (Ra) of the coating layer is less than 0.2 μm, the writability is poor, and when the roughness exceeds 1.0 μm, the flatness,
The transparency deteriorates and it cannot be used. The preferred roughness is 0.4-
It is in the range of 0.9 μm. The roughness of the coating layer surface can be controlled by a conventionally known method, such as a method of sandblasting the base film before providing the coating layer, a method of blending the above-mentioned fine particles in the film, and the like. It is preferable to use a method of incorporating fine particles therein.

The coating layer of the film of the present invention is provided by coating the polyester film with the above-mentioned graft copolymer, fine particles optionally added, and a white pigment dissolved or suspended in a solvent and drying. You can

The coating method is, for example, "Coating method" by Yuji Harasaki.
(1979 Maki Shoten) reverse roll coater,
Although it can be carried out using a coating device such as a gravure coater, a rod coater, and an air doctor coater, a coating agent containing the graft copolymer of the present invention has a dispersibility such as added fine particles or a white pigment, And since it has excellent coating characteristics, there is no particular limitation on the coating apparatus.

The coating liquid is dried in a heating zone (infrared heater, furnace having a dielectric heating device, etc.), and further subjected to aging treatment as necessary to improve the adhesion of the coating layer to the base film and the strength of the coating layer. However, since the coating agent containing the graft copolymer of the present invention is excellent in both the adhesion to the base film and the strength of the coating layer, it may be dried at a relatively low temperature for a short time, and aging is also particularly required. do not do.

The tracing film of the present invention can be produced by appropriately selecting such a method, but the thickness of the coating layer is preferably 0.5 to 10 g / m ² , and more preferably ² to 7 g / m ^2. m ² . If the thickness of the coating layer is less than 0.5 g / m ² , the writability and abrasion resistance are insufficient, and if the thickness of the coating layer exceeds 10 g / m ² , the processing efficiency becomes extremely poor and the cost becomes high. Appropriate.

Further, an intermediate layer may be provided between the coating layer and the polyester film in order to improve the adhesion between the coating layer of the present invention and the base polyester film or the characteristics of the tracing film. When the intermediate layer is provided, the total thickness of the coating layer and the coating layer is preferably in the range of 1 to 10 g / m ² , and more preferably ² to 7 g / m ² .
As the intermediate layer, a polyester resin, an acrylic resin, an epoxy resin, a polyurethane resin, or the like is used, but the intermediate layer is not limited thereto.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to the following examples unless the gist thereof is exceeded. The evaluation of each characteristic in the examples was performed according to the following methods.

(1) High-speed writing: 30 m / mi with a ballpoint pen automatic drawing machine
High-speed writing was performed with n, and the blurring of lines was visually judged.

(⊚; excellent, ∘; good, Δ; acceptable, ×; not acceptable) (2) Poster color writability: Water-based ink (poster color) was drawn on a sample with a writing brush, and the repellency of the ink was visually determined.

(⊚; excellent, ∘, good, △; acceptable, ×; not possible) (3) Solvent resistance: judged by the high-speed writability described in (1) after wiping the surface of the coating film 5 times with gauze containing toluene. did.

(⊚; excellent, ∘; good, Δ; acceptable, ×; not acceptable) (4) Abrasion resistance: rubbing the coated surface with a melon and determining by scratch marks.

(◎; excellent, ○; good, △; acceptable, ×; not acceptable) (5) Surface roughness: according to the method described in JIS B0601-1976
A surface roughness measuring instrument model SE-3F manufactured by Kosaka Laboratory was used. The center line average roughness (Ra) was measured under the conditions of a stylus diameter of 5 μm, a load of 30 mg, a cutoff value of 0.08 mm, and a measurement length of 2.5 mm.

Example 1 The backbone is polymethylmethacrylate (RMMA) and the branch is 2-hydroxyethylmethacrylate (2-HEMA)
And a graft copolymer (PMMA / 2-HEMA / N-MAM = 75 / 12.5 / 1) which is N-methylol acrylamide (N-MAM).
2.5) Methyl cellosolve solution 100 parts (solid content 25 wt%),
6 parts of SiO ₂ particles with an average particle size of 3 μm, TiO with an average particle size of 0.4 μm
_A 100 μm thick polyester film (Diafoyle T # 100) was coated with a coating solution consisting of 1 part of ₂ particles, 16 parts of toluene and 30 parts of methylethylmethone using a roll coater and dried at 80 ° C. for 20 seconds. A tracing film with a coating of 4 g / m ² was obtained.

Comparative Example 1 90 parts of a varnish containing a homopolymer of methyl methacrylate in place of the graft copolymer in the coating solution used in Example 1 (Dianal LR-269 (trade name) manufactured by Mitsubishi Rayon Co., Ltd., solid content 30 wt%) and A coating liquid of the same composition was prepared except that 10 parts of a varnish containing polyisocyanate (Coronate HL (trade name) manufactured by Nippon Polyurethane Company, solid content: 75 wt%) was mixed, and applied to a polyester film in the same manner as in Example 1 and dried. Then, the adhesion of the coating film to the polyester film and the strength of the coating film were improved by aging treatment at 40 ° C. for 48 hours to obtain a tracing film having a coating film of about 4 g / m ² .

Example 2 The coating layer of the film obtained in the same manner as in Comparative Example 1 except that the coating thickness was about 2 g / m ² in Comparative Example 1 was used as an intermediate layer, and the coating liquid used in Example 1 was applied thereon. Apply, dry,
A tracing film having a total coating film thickness of about 4 g / m ² was obtained.

Comparative Example 2 The coating film thickness was about the same as in Example 1 except that a coating solution containing no SiO ₂ particles having an average particle size of 3 μm was used.
A tracing film of 4 g / m ² was obtained.

Comparative Example 3 Instead of the graft copolymer in the coating liquid used in Example 1, a linear polyester resin (Vylon 20 manufactured by Toyobo Co., Ltd.) was used.
A coating solution having the same composition except that 100 parts of SS (brand name) solid content 30 wt%) is mixed, coated on a polyester film in the same manner as in Example 1, dried, and tracing having a film thickness of 4 g / m ² I got a film.

(Effects of the Invention) The tracing film of the present invention has excellent writability for various writing means, solvent resistance, coating film adhesion, flatness, etc. It is suitable for various applications.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B32B 27/36 B32B 27/36 C08J 7/04 CFD C08J 7/04 CFDZ

Claims (1)

(57) [Claims] 1. A polyester film having a coating layer containing a graft copolymer resin having an acrylic polymer as a trunk chain and a hydroxyl group-containing acrylic polymer as a branch chain on one side, and the roughness of the coating layer surface ( Ra) is 0.2 to 1.0 μm, a tracing film.