JP3150772B2 - Drafting film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drafting film used for tracing, electrostatic recording, and the like, and more particularly to a drafting film in which a dimensional change due to humidity is reduced.

[0002]

2. Description of the Related Art Drafting films for design and drafting are more tough, more stable to changes in temperature and humidity, more water-resistant, and more stable than paper-based drafting paper. Due to its stability and other characteristics, it is used especially for precise design drawings. Conventional drafting films are used as a recording medium receiving layer by coating and drying a solution of a binder synthetic resin containing a matting agent of an inorganic or organic filler in a solvent on both sides of a plastic film such as a polyethylene terephthalate film and drying. The recording medium receiving layer was formed directly on both sides of the plastic film.

[0003] The main plastic films include:
Polyesters such as polyethylene terephthalate are used because of factors such as optical suitability (transparency), mechanical strength, heat resistance, versatility and low cost. In recent years, computer-based design management systems have become widespread,
Drawings are automatically plotted by various methods such as ballpoint pen, pencil, lot ring, thermal transfer, toner, ink jet, etc., especially when outputting for a long period of time, due to changes in the humidity of the working environment during that time, plastic that becomes the center Problems such as loss of image consistency due to expansion and contraction of the film occur. When such inconvenience occurs, the output is restarted from the beginning again, resulting in a great decrease in work efficiency.

Also, depending on the storage method, a part of the film is stretched due to moisture absorption due to a change in environmental humidity and the flatness is not maintained, resulting in a wavy state, which hinders the operation of the automatic plotter. There was also a disadvantage. Some plastics have a small dimensional change due to humidity, but could not be used in place of polyester due to factors such as optical aptitude (transparency), mechanical strength, heat resistance, solvent resistance, and price.

In order to reduce the influence of humidity, conventionally,
Although an expensive air-conditioning system was introduced to stabilize the working environment (stabilization of humidity), the development of a drafting film that is potentially stable to humidity has been desired. In the field of packaging materials, it is widely used to provide a film of a substance having a low water vapor transmission rate on the surface of a plastic film for the purpose of preventing moisture permeation, preventing food from drying, and preventing odor from entering. In order to stabilize the rafting film with respect to humidity, a film made of a substance having a low water vapor transmission rate has not been provided on the plastic film.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a drafting film which is less affected by humidity.

[0007]

Means for Solving the Problems In order to achieve such an object, the present inventors have made intensive studies and as a result, by covering both surfaces of a plastic with a film of a material having a low water vapor transmission rate, the humidity relative to the dimensions was reduced. The inventors have found that the influence can be extremely reduced and completed the present invention. The drafting film according to the present invention is a film in which a film of a substance having a lower water vapor transmission rate than the plastic film is provided on both surfaces of the plastic film, and a recording medium receiving layer is provided on at least one of the films.

That is, a substance having a low water vapor transmission rate transmits only a small amount of water vapor from the atmosphere, and thus limits the amount of water vapor reaching the central plastic film. This is because dimensions can be maintained. Examples of the plastic film used in the present invention include polyethylene terephthalate, polypropylene, polycarbonate, polyvinyl chloride, polyethylene, and polymethacrylate, but are not particularly limited thereto.

The substance having a low water vapor transmission rate used in the present invention includes silicon and aluminum, titanium, selenium, magnesium, barium, zinc, tin, indium,
Inorganic metal compounds such as calcium, tantalum, zirconium, thorium, thallium, etc., or halides alone or in mixtures, ceramics such as glass,
Copolymer of vinylidene chloride with vinyl chloride, acrylonitrile or acrylic, polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkylvinyl ether copolymer ( Synthetic resins such as PFA) are preferred.

Of these substances, inorganic metal compounds and ceramics have a high effect of restricting water vapor permeation even at a thin film thickness, and hardly dissolve or swell in organic solvents and the like, as compared with synthetic resins. It is particularly excellent as a substance having a low water vapor transmission rate, for example, when a recording medium receiving layer is provided on this film, there is no restriction on paint design.

The water vapor transmission rate of these substances is determined by using an inorganic metal compound (polyethylene terephthalate 12 μm
If as an example what was deposited ₂ 0.04 .mu.m) is approximately 1g / m ² / 24hrs, water vapor transmission rate is significantly reduced as compared to 40g / m ² / 24hrs only polyethylene terephthalate, synthetic resin in each case, approximately in the thickness 100μm 0.2~1.5g / m ^2/24
hrs and the thickness of polyethylene terephthalate is 10
It has become a little water vapor transmission rate as compared with about 6.9g / m ² / 24hrs at 0 .mu.m.

The method of providing a uniform film of the above substance having a low water vapor transmission rate on the surface of a plastic film includes an inorganic metal compound and, in the case of ceramics, a vacuum evaporation method.
A sputtering method, an ion plating method, or the like is used. In the case of synthetic resins, a method in which they are dissolved in an organic solvent and applied and dried, a method in which they are hot-melted and extruded, a method in which a separately prepared synthetic resin film is laminated using an adhesive, Known methods such as an evaporation method and a sputtering method are used.

The thickness of the film of a substance having a low water vapor transmission rate provided on the surface of the plastic film by the above-described method is particularly low in the case of inorganic metal compounds and ceramics having a low water vapor transmission rate. The dimensional stability is obtained, and the film can follow the flexibility of the plastic film, and the film can be prevented from falling off due to the occurrence of cracks, in the range of 0.01 μm to 0.5 μm, more preferably, 0.02 μm to 0.3μ
m.

Further, in the case of a synthetic resin, a range of 1 μm to 50 μm is preferable, in which sufficient dimensional stability is obtained and the total thickness of the drafting film is appropriate. In order to enhance the adhesion of the substance having a low water vapor transmission rate to the plastic film, it is preferable to perform a pre-treatment such as a discharge treatment or a chemical treatment or an anchor treatment in advance on the film surface in order to improve the adhesion.

The recording medium receiving layer when used as a tracing film is obtained by uniformly applying and drying a coating solution in which a binder synthetic resin containing a matting agent of an inorganic or organic filler is dissolved in a solvent. Matting agents include silicon dioxide, clay, calcium carbonate,
Inorganic fillers such as aluminum hydroxide and titanium oxide, and powdered organic fillers such as benzoguanamine, melamine, and cellulose are suitable, but not limited thereto.

Epoxy, as the binder synthetic resin,
Urethane, melamine, cellulose, linear polyester, acrylic, styrene / acrylic copolymer and the like are suitable, but not limited thereto. These coating solutions are uniformly applied by a known method such as a reverse roll, a wire bar, or a die and dried.

According to the method described above, the thickness of the recording medium receiving layer provided on at least one of the films of the substance having a low water vapor transmission rate is such that irregularities are formed on the surface of the film, and writing performance with various writing instruments is sufficiently obtained. The thickness is in the range of 1 μm to 20 μm, and more preferably in the range of 3 μm to 10 μm, which ensures light transmittance suitable for the duplication operation.

The recording medium receiving layer when used as an electrostatic recording film comprises a conductive layer and a dielectric layer.
The conductive layer is obtained by uniformly applying and drying a coating solution obtained by dissolving a synthetic resin binder containing an ion conductive substance or an electron conductive substance in a solvent. As the ion conductive material, cationic polymer electrolytes such as triethylammonium styrene acrylate and polyvinylbenzyltrimethylammonium chloride; and anionic polymer electrolytes such as polyvinyl phosphate and polystyrene sulfonate are preferable. However, the present invention is not limited to this.

The electron conductive substance is preferably, but not limited to, metal semiconductor powder in which impurities are mixed in zinc oxide, tin oxide, titanium oxide and the like. As a synthetic resin binder used for the conductive layer,
Synthetic resins such as polymethyl methacrylate, unsaturated polyester, and polystyrene are suitable, but not limited thereto.

As for the thickness of the conductive layer, a uniform resistance value can be obtained,
A range of 0.1 μm to 30 μm is preferable because there is no fear of displacement and the production efficiency is high. However, when the substance having a low water vapor transmission rate has an appropriate conductivity, the conductive layer can be omitted. The dielectric layer is obtained by uniformly applying a coating solution obtained by dissolving a synthetic resin binder containing an inorganic filler in a solvent on the above-mentioned conductive layer and drying.

As the inorganic filler, amorphous silica, calcined amorphous silica, silane-treated silica, calcium carbonate,
Kaolin, calcined kaolin, and synthetic resin pigments such as polyethylene and polyacrylonitrile are suitable, but are not limited thereto. As the synthetic resin binder used for the dielectric layer, synthetic resins such as polyester, polymethyl methacrylate, styrene / acrylic copolymer, butyral, epoxy, and urethane are suitable, but not limited thereto.

The thickness of the dielectric layer is preferably in the range of 1 μm to 30 μm where there is no risk that the conductive layer is exposed and the capacitance is not too small. These coating solutions are uniformly applied by a known method such as a reverse roll, a wire bar, or a die and dried. In order to increase the adhesion of the recording medium receiving layer to the film of a substance having a low water vapor transmission rate, it is preferable to previously perform a discharge treatment, a pretreatment such as a chemical treatment, or an anchor treatment for improving the adhesion of the film surface. .

[0023]

The present invention will be further described with reference to the following examples.
The present invention is not limited to these examples. [Example 1] As shown in FIG. 1, on both sides of a 75 μm thick polyethylene terephthalate film which is a plastic film 1, SiO as a material film 2, 2 ′ having a low water vapor transmission rate of about 0.04 μm by sputtering. _Two coatings were provided uniformly. Further, as the recording medium receiving layers 3 and 3 ', a coating solution obtained by dissolving a linear polyester resin (trade name: Byron 200) containing a matting agent of silicon dioxide in a solvent of methyl ethyl ketone: toluene = 1: 1 is used. ₂ The dry film is 6μm on both sides of the film.
The resultant was uniformly coated and dried to obtain a drafting film.

The humidity expansion and contraction rate of this drafting film was measured according to J-TAPPI. It was 0.2 × 10 ^{−5 as} measured by a measuring method of No. 28 m, and the expansion ratio was about ５ of that of a drafting film of a comparative example described later. [Example 2] Thickness 7 as plastic film 1
On both sides of a 5 μm polyethylene terephthalate film, vinylidene chloride dissolved in 10% by weight of methyl ethyl ketone as a material film 2 or 2 ′ having a low water vapor transmission rate.
The acrylonitrile copolymer is applied and dried, and about 5
A uniform coating of μm was provided. Further, the recording medium receiving layer 3,
3 ′ as the silicon dioxide matting agent and butyral
A coating solution obtained by dissolving a styrene-maleic acid copolymer (8: 2) in a denatured alcohol is uniformly coated on both surfaces of a vinylidene chloride / acrylonitrile copolymer film so as to have a dry film thickness of 6 μm, and is then drafted. A film was obtained.

The humidity expansion and contraction rate of this drafting film was 0.3 × 10 ^-5 , which was about 1/3 that of the drafting film of the comparative example described later. Example 3 Thickness 1 as Plastic Film 1
Quartz glass was sputtered on both surfaces of the 00 μm polyethylene terephthalate film as the material films 2 and 2 ′ having a low water vapor transmission rate, and a uniform film of about 0.05 μm was provided. Further, as the recording medium receiving layers 3 and 3 ′, the coating solution used in Example 1 was uniformly applied on the quartz glass coating on both sides so that the dry film thickness became 6 μm and dried to obtain a drafting film. .

The moisture expansion / contraction rate of this drafting film was 0.2 × 10 ⁻⁵ , which was about 1/5 of that of the later-described comparative example. [Comparative Example] 75 μm thick as plastic film 1
On both sides of the polyethylene terephthalate film having a thickness of m, the coating solution used in Example 1 as a recording medium receiving layer was uniformly applied and dried so that the dried film had a thickness of 6 μm to obtain a drafting film.

The moisture expansion / contraction rate of this drafting film was 1.0 × 10 ⁻⁵ .

[0028]

[Table 1]

As is clear from Table 1, the drafting film of the present invention has a smaller moisture expansion / contraction ratio than the conventional drafting film, and thus is affected by humidity not only during the plotting operation but also during the storage. It is difficult to maintain stable flatness.

[0030]

As is apparent from the above embodiments, the drafting film of the present invention is less susceptible to humidity than the conventionally used drafting film, and therefore has a dimensional change and a flat surface. It is possible to carry out a plotting operation requiring high dimensional accuracy under normal working environment without causing sexual abnormalities or the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a drafting film according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Plastic film 2, 2 '... Material film with low water vapor transmission rate 3, 3' ... Recording medium receiving layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B42D 15/00 B32B 27/00 B32B 7/02

Claims (1)

(57) [Claims] 1. A drafting film comprising: a film of a substance having a lower water vapor transmission rate than said plastic film; and a recording medium receiving layer provided on at least one of said films.