WO1999056179A2

WO1999056179A2 - Transparent film for image recording and method of producing image recorded film

Info

Publication number: WO1999056179A2
Application number: PCT/US1999/006851
Authority: WO
Inventors: Koji Kamiyama; Shigeaki Dohgoshi
Original assignee: Minnesota Mining And Manufacturing Company
Priority date: 1998-04-28
Filing date: 1999-03-31
Publication date: 1999-11-04
Also published as: WO1999056179A3; JPH11338180A

Abstract

The present invention is directed to a transparent film for image recording, comprising a toner accepting layer having improved compatibility with a resin of a wax-containing toner, which is capable of forming a color image having high transparency. A transparent film for image recording, comprising a transparent substrate and a toner accepting layer provided on at least one major surface of said substrate, said toner accepting layer containing a styrene copolymer, wherein a SP value determined by the Small's method of said styrene copolymer is within the range from 8.0 to 9.5

Description

Transparent Film for Image Recording and Method of Producing Image Recorded Film

Field of the Invention

The present invention relates a transparent film for image recording suited for production of an image recorded film having a light transmitting image formed form a wax-containing toner, which can be used as a overhead projector (hereinafter referred to as "0HP"),and a method of producing an image recorded film using the same .

Background A transparent film for image recording, which has hitherto been used in case of generally forming a fullcolor image for OHP using an electrophotographic system, comprises a transparent substrate and a toner accepting layer (also referred to as an "accepting layer") provided on at least one major surface of the substrate, normally. The toner accepting layer contains a thermoplastic polymer, normally. However, there is a limit in enhancement of the compatibility between the accepting layer and toner (particularly, resin of toner) and the transparency (e.g. represented by a "color transmission factor") of the image tends to be lowered.

Therefore, it has been suggested to contain a plasticizer in a toner accepting layer to enhance the compatibility between the accepting layer and toner. For example, Japanese Unexamined Patent Publication (KOKAI) No. 9-152736 and U.S. Patent Nos . 5,006,407 and No. 5,317,000 discuss a transparent film for recording, comprising a toner accepting layer containing a polymer having comparatively high SP value (solubility parameter) and a plasticizer which is compatible with the polymer. Polymers having comparatively high SP value, for example, a polyester, a vinyl methyl ether-maleic acid copolymer, a cellulose derivative, an aromatic vinyl (meth) acrylic copolymer, etc., are discussed. A so-called aromatic plasticizer having comparatively high SP value (e.g. not less than 9.6), which has an aromatic ring in the molecule, is discussed as the plasticizer which is compatible with the polymer. The polymer having comparatively high SP value is used because the resin contained in the toner is also formed from the polymer having comparatively high SP value, such as polyester, etc. In case of such a toner accepting layer containing a plasticizer, the compatibility between the accepting layer and toner is enhanced and the transparency of the image is improved. On the other hand, the above toner accepting layer containing the thermoplastic polymer is liable to offset to an image fixing roller on fixing. In order to prevent such an offset (normally referred to as "hot offset"), a trial of improving the releasability of the accepting layer from the fixing roller by containing a releasant such as wax, etc. in the toner has been made. However, when a full-color image is formed on a film by using the releasant, the transparency of the toner image after fixing is drastically lowered. It is believed that, since the SP value of wax is comparatively low (e.g. not more than 9.5), the compatibility between the polymer having comparatively large SP value (e.g. not less than 10) of the accepting layer and toner resin containing wax is inhibited by the existence of wax. It is also considered as the cause that the SP value of the toner resin is comparatively low in view of the compatibility with wax. Furthermore, wax breeding from the toner after fixing is remained on the image surface and the transparency of the image is lowered by breeding wax. Therefore, a transparent film capable of coping with the toner containing wax as the releasant (wax-containing toner) has also been suggested. For example, Japanese Unexamined Patent Publication (KOKAI) Nos. 5-181300 and 6-75418 respectively discuss a transparent film for image forming, comprising a substrate layer and a toner accepting layer capable of absorbing a wax component . In the former publication, the toner accepting layer comprises an absorbing layer of inorganic particles. In the latter, the accepting layer is composed of a resin containing a diene component, such as polybutadiene, etc. In these films, wax breeding from the toner prevents hot offset on fixing and, besides, wax breeding from the toner after fixing is absorbed and it is possible to effectively prevent excess wax from remaining on the image surface.

However, regarding the transparent film capable of coping with the above wax-containing toner, the intrinsic effect of the toner absorbing layer, i.e. compatibility between the accepting layer and toner resin (mixture of resin and wax) , is low and it was difficult to improve the transparency of the image . Japanese Unexamined Patent Publication (KOKAI) No. 63-178074 discusses a transparent film for recording, comprising an accepting layer containing a styrenebutadienen copolymer latex and/or a modified styrenebutadiene copolymer latex and colloidal silica having an average particle diameter of 3 to 100 nm, but apparently does not disclose any problems in case of using the wax-containing toner and any means for solving the problems .

Summary of the Invention

The present invention is directed to a transparent film for image recording, comprising a toner accepting layer having improved compatibility with a resin of a wax-containing toner (mixture of resin and wax) , which is capable of forming a color image having high transparency.

In one aspect, the present invention provides a transparent film for image recording, comprising a transparent substrate and a toner accepting layer provided on at least one major surface of said substrate, said toner accepting layer containing a styrene copolymer, wherein a SP value determined by the Small's method of said styrene copolymer is within the range from 8.0 to 9.5.

In another aspect, the present invention provides a transparent film for image recording, comprising a transparent substrate and a toner accepting layer provided on at least one major surface of said substrate, said toner accepting layer containing a styrene copolymer and a plasticizer dispersed in said styrene copolymer, wherein an SP value determined by the Small ' s method of said plasticizer is within the range from 8.0 to 9.5.

Furthermore, the present invention provides a method of producing an image recorded film, which comprises adhering a wax-containing toner on a surface of a toner accepting layer of a transparent film for image recording of the present invention to form a toner image; and pressing said toner image onto said toner accepting layer while heating at a temperature higher than a softening point of said styrene copolymer to embed said toner image into said toner accepting layer, thereby fixing said toner image to said toner accepting layer.

Detailed Description of the Invention The operation and embodiment of the present invention will be described in detail hereinafter.

In the first embodiment of the present invention, the toner accepting layer contains a styrene copolymer and the SP value determined by the Small's method of the styrene copolymer is within the range from 8.0 to 9.5. Such a toner accepting layer is, for example, a coat formed by applying a coating solution containing a styrene copolymer latex (aqueous dispersion) , followed by drying . In the second embodiment of the present invention, the toner accepting layer contains a styrene copolymer and a plasticizer dispersed in the copolymer, and the SP value determined by the Small ' s method of the styrene copolymer is within the range from 8.0 to 9.5. Namely, in both cases of the first and second embodiments, the SP value of the toner accepting layer is easily controlled within comparatively narrow range (e.g. within the range from 8.0 to 9.5) to enhance the compatibility between the toner resin (mixture of resin and wax) , thereby making it possible to effectively reduce the transparency (e.g. color transmission factor, etc . ) of the image .

In case of the second embodiment, when the styrene copolymer and plasticizer are contained in the accepting layer in the state of being uniformly compatibilized, the transparency of the image can be enhanced, more efficiently. The uniform state of the styrene copolymer and plasticizer can be accomplished by forming a toner accepting layer from a coating solution, which is formed by dispersing the above plasticizer in a latex containing a styrene copolymer dispersed therein. The term "SP value" used herein is a value determined by the Small ' s method. The Small's method is disclosed in detail, for example, in P. A. Small, J. Appl . Chem. , 3, 71 (1953).

When the SP value of the styrene copolymer is less than 8, the compatibility in the toner resin is lowered. On the other hand, when the SP value exceeds 9.5, the compatibility in toner wax is lowered. In both cases, the transparency of the image can not be effectively enhanced. It is also necessary that the SP value of the plasticizer is within the above range by the same reason. In the first embodiment, a plasticizer having the SP value within the range from 8.0 to 9.5 is contained, in addition to the above styrene copolymer, the transparency of the image can be enhanced, more effectively. As the above plasticizer (having the SP value within the range from 8.0 to 9.5), those containing an aliphatic ester plasticizer are preferable. This plasticizer is superior in effect of improving the transparency of the image because its solubility in the styrene copolymer, toner resin and toner wax is particularly high. The plasticizer to be used may be a simple substance or a mixture. In case of the mixture, the proportion (% by weight) of the aliphatic ester plasticizer contained in the whole plasticizer is decided so that the SP value of the whole plasticizer is within the above range, but is normally from 55 to 100% by weight.

On the other hand, the styrene copolymer has comparatively low sharp melt property and its effect for sedimentation of the toner, after fixing, into the accepting layer is comparatively low, sometimes. However, the above effect can be easily accomplished with the help of the above plasticizer. That is, the toner after fixing is allowed to sediment into the accepting layer to effectively prevent the irregularity from remaining on the surface of the toner image, thereby making it possible to further improve the clarity and transparency of the image .

When the toner image is formed by using a wax- containing toner, the styrene copolymer having the SP value within the above range can inhibit crystal growth of wax bleeding from the toner on fixing to effectively prevent white turbidity (light scattering) caused by crystallization of wax, thereby making it possible to prevent the transparency of the image from lowering. Also in case of the mixture of the styrene copolymer and plasticizer, white turbidity caused by crystallization of wax can be prevented, thereby making it possible to prevent the transparency of the image from lowering. And besides, an intrinsic function of wax, i.e. effect of preventing hot offset to prevent lowering of the smoothness of the image surface caused by offset.

Transparent Substrate

The transparent substrate (hereinafter, referred merely to as a "substrate") used in the present invention can be selected from normal polymer films having high transparency. Preferred is a film having a thickness of about 25 to 175 μm, which is superior in transparency, heat resistance, strength and rigidity. Specific examples of the preferable polymer include polyethylene terephthalate . In addition, polymers such as polyolefin, polycarbonate, acrylic, polyvinylidene fluoride, etc. can also be used.

Toner Accepting Layer

The styrene copolymer is normally commercially available as a latex prepared by suspension polymerization or emulsion polymerization. The weight average molecular weight of the styrene copolymer is normally from 20,000 to 5,000,000. A weight ratio (S:M) of a styrene unit (S) to a monomer unit (M) other than the styrene unit in the molecule is normally from 55:45 to 99:1.

The styrene copolymer is preferably a styrenebutadiene copolymer or a styrene-acrylic copolymer. These styrene copolymers are superior in compatibility with the above plascticizer (having the SP value of 8.0 to 9.5) and effectively enhance the compatibility between the resin of the wax-containing toner and accepting layer. In addition, these styrene copolymers are particularly superior in compatibility with an aliphatic ester plasticizer. It is particularly preferred that the toner accepting layer has a softening point lower than that of the toner. The reason is as follow. That is, the melting (or softening) degree of the toner becomes than the softening degree of the toner accepting layer by pressing under high-temperature conditions in the toner fixing operation, thereby making it possible to smooth the image surface while maintaining the resolution of the toner image .

Since the toner, which is exclusively used in the technical filed of electrophotography at present, has a melting point within the range from 95 to 200°C, the toner accepting layer preferably have a softening point within the range from 90 to 195 °C. The term "softening point" used in this specification refers to a temperature at which a solid resin is converted into a rubber- like form by softening, or a temperature at which the crystalline portion in the molecule is molten. This softening point is measured by the ring and ball method or needle penetration method. The styrene copolymer of the toner accepting layer may be a single substance or a mixture of two kinds of them. In case of the mixture, the SP value of the whole polymer is preferably within the range from 8.0 to 9.5.

To enhance the compatibility with the toner resin, a polymer (or resin) other than the styrene copolymer can be contained. Specific examples of such a polymer (or resin) include polyester, epoxy resin, acrylic resin, polyurethane, etc. For example, when the toner is composed of :

(1) a core containing wax, a styrene copolymer having good compatibility with wax, and a coloring pigment, and

(2) a shell containing a polyester for coating the core, the polymer of the toner accepting layer is preferably a mixture of the styrene copolymer and polyester. Consequently, the compatibility between the toner and accepting layer is effectively enhanced, thereby making it possible to enhance the transparency of the image regardless of the transmission optical density. To obtain such an effect, a mixing weight ratio (S:P) of the styrene copolymer (S) to the polymer (P) other than the styrene copolymer is preferably within the range from 50:50 to 90 :10.

A storage modulus at 160°C of the accepting layer is preferably adjusted within the range from 1 x lO⁴ to 1 x 10⁷ dyne/cm². When the storage modulus is not more than 1 x 10⁴ dyne/cm², there is a fear of failing to prevent lowering of the smoothness of the image surface caused by hot offset. On the other hand, when the storage modulus exceeds 1 x 10⁷ dyne/cm², sedimentation of the toner into the accepting layer becomes insufficient and there is a fear of remaining the irregularity on the surface of the image. The storage modulus is a value measured by a viscosity measuring device (e.g. "Dynamic Analyzer RDA" , manufactured by Rheometrics Co.) at a temperature step mode for raising a measuring temperature and a shear mode of a frequency of 100 rad/sec, using a "disposable cup" having a diameter of 25 mmφ and a height of 5 mm as a sample holder.

A surface resistance of the toner accepting layer is normally from 1 x 10⁸ to 1 x 10¹³ Ω /D.

Plasticizer

As the above plasticizer, for example, an aliphatic ester plasticizer is preferable. The "aliphatic ester plasticizer" is ® an ester of a fatty acid and an alcoholic compound or © an ester of an aliphatic alcohol and an acid. Examples thereof include aliphatic dibasic acid esters such as diisodecyl succinate, dioctyl adipate, diisodecyl adipate, dioctyl azelate, dibutyl sebacate, dioctyl sebacate, dioctyl tetrahydrophthalate, dibutoxyethyl adipate, etc. These aliphatic ester plasticizers can enhance the above compatibilization operation and crystal growth inhibition operation, particularly.

The content of the aliphatic ester plasticizer is normally within the range from 0.5 to 75 parts by weight, preferably form 1 to 50 parts by weight, particularly from 2 to 30 parts by weight, based on 100 parts by weight of the styrene copolymer of the accepting layer. When the content is too small, there is a fear of lowering the above compatibilization operation and crystal growth inhibition operation. On the other hand, when the content is too large, there is a fear of arising sticking of the surface, blocking of the film, etc. Other Additives

As far as the above characteristics such as transparency, modulus, softening point, etc., of the toner accepting layer are not adversely affected, additives such as antistatic agents, surfactants, antioxidants, inorganic particles, polymer particles, ultraviolet absorbers, etc. may be contained in the accepting layer.

Among them, particularly preferable additives are ultraviolet absorbers. For the purpose of realizing high resolution and excellent transparency of the toner image, refining of the toner particles have recently been performed, but the refining may cause light resistance of the resulting image. However, it becomes possible to remarkably improve the light resistance of the image to a light source for OHP or light from the outside by using the toner accepting layer containing an ultraviolet absorber of the present invention. The ultraviolet absorber is generally used in the amount of 40 to 85 parts by weight based on 100 parts by weight of the resin used in the toner accepting layer.

Thermoplastic Toner

The toner used for forming a toner image on the transparent film for image recording of the present invention may be any wax-containing thermoplastic toner used in the technical field of forming an electrophotographic image, and is not specifically limited. For example, it is a toner containing a thermoplastic polymer (resin) such as styrene (meth) acrylic acid copolymer, styrene-acrylate copolymer, bisphenol A epoxy resin, polyester, etc. As wax, for example, ester wax, paraffin wax, polyolefin wax, etc., can be used. Preferable wax is ester wax and those represented by the general structural formula ® to © are particularly preferable.

(CH₂)_MOCOR²]_b

wherein a and b represents an integer of 0 to 4 and a + b = 4; R¹ and R² represent an alkyl group having 1 to 40 carbon atoms and a difference in the number of carbon atoms between R¹ and R² is not less than 10; and m and n represent an integer of 0 to 15 and m and n do not represent 0, simultaneously.

[R¹0C0(CH₂)_n]_aC[ (CH₂)_m0H]_b

wherein a and b represents an integer of 1 or 2 and a + b = 2 or 3 ; R¹ represents an alkyl group having 1 to 40 carbon atoms; and m and n represent an integer of 0 to 15 and m and n do not represent 0, simultaneously.

<General structural formula ® of ester wax> [R^x0C0 (CH₂) _aCR³ ₄._a._b [ (CH₂) _m0C0R²] _b

wherein a and b represents an integer of 0 to 3 and a + b = 2 or 3 ; R¹ and R² represent an alkyl group having 1 to 40 carbon atoms and a difference in the number of carbon atoms between R¹ and R² is not less than 10; and m and n represent an integer of 0 to 15 and m and n do not represent 0, simultaneously.

R'COOR²

wherein R¹ and R² represent an alkyl group having 1 to 40 carbon atoms; the number of carbon atoms of R¹ and R² may be the same or different; and the total number of carbon atoms of R¹ and R² is no less than 10.

R¹COO(CH₂)_nOOCR²

wherein R¹ and R² represent an alkyl group having 1 to 40 carbon atoms; n represents an integer of 2 to 20; the number of carbon atoms of R¹ and R² may be the same or different; and the total number of carbon atoms of R¹ and R² is no less than 10.

R¹OOC(CH₂)_nOOCR²

The content of wax is normally within the range from 5 to 40 parts by weight based on 100 parts by weight of the resin of the toner.

On the other hand, an average particle diameter of the toner is not specifically limited, but is preferably from about 6 to 30 μm in view of the resolution. By using toners of the three primary colors such as cyan, magenta and yellow in the image recorded film of the present invention, the image recorded film having a color image can be obtained.

Method Of Producing Transparent Film For Image Recording The film for image recording of the present invention can be obtained by laminating a toner accepting layer on a transparent substrate. The laminating method is not specifically limited, but examples thereof include a method of applying a coating solution containing the above polymer and plasticizer on a transparent substrate by using a Meyer coater, followed by drying.

The coating solution can be prepared by using a normal stirring device (e.g., high-speed mixer, etc.) of paint . A thickness of the toner accepting layer after drying is preferably from 0.5 to 10 g/m² in case of defining by a coating weight. When the thickness is less than 0.5 g/m², the desired effect is not sufficiently obtained. On the other hand, when the thickness exceeds 10 g/m², the light transmission property is inhibited to exert a bad influence on the clarity of the injected image . The thickness is preferably within the range from 0.5 to 20 μm in case of representing by physical dimension.

It is preferred that the accepting layer is laminated after subjecting the surface in contact with the accepting layer of the substrate to a treatment for easy adhesion, such as primer coat treatment, etc. For example, a resin containing a chlorine atom-containing polymer such as polyvinylidene chloride, chlorinated polypropylene, etc., is applied as a primer. The thickness of the primer layer is normally from 0.05 to 3 μm.

Method Of Producing Image Recorded Film To form a clear image having excellent transparency on a transparent film for image recording in case of projecting using OHP, an image is formed on the transparent film for image recording according to electrophotography, first. Then, toner particles of the image are fixed in a toner accepting layer by passing the transparent film for image recording with the toner image through a fixing hot-press roller.

In this heating and pressing step, the toner accepting layer is softened or molten, but it is preferred that the resin of this accepting layer has a softening point lower than that of the toner used in formation of the image and, furthermore, the melting (or softening) degree of the toner is higher than the softening degree of the toner accepting layer. Consequently, the toner particles pressed by the roller are effectively embedded into the accepting layer and each space between the toner particles is filled with the toner accepting layer and, therefore, the surface of the image is effectively smoothed. As a result, scattering of transmitted light is prevented so that the transparency of the projected image is improved and, furthermore, the brightness and chroma are also improved. It is preferred that the temperature of the hotpress roller is higher the softening point of the toner accepting layer. When the temperature of the hot-press roller is lower than the softening point of the accepting layer, the toner particles are not embedded into the toner accepting layer even if they are pressed by the roller. Therefore, the image surface is not sufficiently smoothed.

Examples

The present invention will be described in more detail with reference to the following examples. It will be appreciated that the present invention is not limited to the following examples. In the following examples, "parts" are by weight unless otherwise stated.

Example 1

Styrene-butadiene copolymer latex [DL-460 manufactured by Asahi Kasei Co., Ltd: SP value

8.7, content of styrene units (based on the total weight of the copolymer = 65% by weight)

23.64 Parts N, N-bis (2-hydroxymethyl) -N- (3'-dodecyloxy-2'- hydroxypropyl) methylammonium methylsulf te (Cyastat 609 manufactured by American Cyanamid Co . )

0.20 Parts Polymethyl methacrylate beads (manufactured by 3M Co.)

0.05 Parts Di 2-ethylhexyl adipate (Sansosizer DOA, SP value = 8.6, manufactured by Shin-Nippon Rika Co., Ltd.)

1.13 Parts 1-methyl-2 -pyrrolidone 5.64

Parts

Isopropyl alcohol 29.54

Parts

Deionized water 40.28 Parts

Paint for forming a toner accepting layer of the above composition was coated on both surfaces of a polyethylene terephthalate film having a thickness of 125 μm, wherein a polyvinylidene chloride primer was previously applied on both principal surface, in the amount enough to obtain a dry coating weight of 2.2 g/m² using a Meyer bar. The coated solution was dried by allowing to stand at 100 °C for 2 minutes to form an accepting layer, thereby producing a transparent film for image recording of this example.

Using the transparent film for image recording of this example and an ester wax-containing toner, a toner image of a single yellow color was formed on a toner accepting layer according to an electrophotographic system to obtain an image recorded film. According to the above system, an image recorded film was obtained by adhering a wax-containing toner on the surface of a toner accepting layer to form a toner image; pressing the toner image onto the toner accepting layer while heating at a temperature higher than a softening point of the above styrene copolymer to embed the toner image into the toner accepting layer; and fixing the toner image to the toner accepting layer. The toner image thus obtained was a clear transparent image without causing hot offset. The above ester wax-containing toner had a double structure composed of a core containing a styrene copolymer and a shell containing a polyester.

Using a Haze meter "TC-C III" manufactured by Tokyo Denryoku Co., Ltd., a color transmission factor of the above image recorded film was measured. The color transmission factor was determined by the following equation.

Color transmission factor = { (decrease due to absorption) + (decrease due to scattering) / (decrease due to absorption) }

(The color transmission factor of 1 is a lower limit in the state where decrease due to scattering does not arise . )

A transmission optical density at the measuring point of the color transmission factor was measured by using a Macbeth densitometer TR-924 manufactured by Macbeth Co. The respective results are shown in Table 2. As is apparent from the results, regarding the image recorded film of the present example, both portion having high transmission optical density and portion having low transmission optical density show small color transmission factor (e.g., high transparency) .

Example 2 According to the same manner as that described in Example 1 except for using no di 2-ethylhexyl adipate, a transparent film for image recording and an image recorded film of this example were produced and then evaluated. The results are shown in Table 1 below. In the image recorded film of this example, the color transmission factor at the portion having high transmission optical density (the amount of toner is large) can be reduced similar to Example 1. However, it was difficult to reduce the color transmission factor at the portion having low transmission optical density (the amount of toner is small) .

Example 3

According to the same manner as that described in Example 1 except for using a plasticizer having a SP value of 9.9 (EB200, manufactured by Sanyo Kasei Kogyo Co., Ltd.) in place of di 2-ethylhexyl adipate, a transparent film for image recording and an image recorded film of this example were produced and then evaluated. The results are shown in Table 1 below. In the image recorded film of this example, the color transmission factor at the portion having high transmission optical density (the amount of toner is large) can be reduced similar to Example 1. However, it was difficult to reduce the color transmission factor at the portion having low transmission optical density. Comparative Example 1

For comparison, according to the same manner as that described in Example 1 except for using a commercially available transparent film for image recording (CG3700, manufactured by 3M Co.) as an image, a transparent film for image recording and an image recorded film of this example were produced and then evaluated. The results are shown in Table 1 below. The toner accepting layer of this transparent film for image recording was formed by using an acrylic resin.

The image recorded film of this example has high color transmission factor in comparison with Example 1, regardless of the transmission optical density.

Table 1

Transmission Color

Example No. Optical density Transmission Factor Example 1 1.06 5.45 0.25 9.34

Example 2 1.01 5.53 0.22 >20.00

Example 3 1.06 5.96 0.22 11.61

Comp . Example 1 1.05 7.74 0.20 >20.00

Example 4

Styrene-acrylic copolymer latex [Y-8346 manufactured by Nippon Carbide Co., Ltd: SP value = 9.1, content of styrene units (based on the total weight of the copolymer = 69% by weight)

22.55 Parts Effcoal 214 (antistatic agent, manufactured by Matsumoto Yushi Seika Co., Ltd.)

0.23 Parts Polymethyl methacrylate beads (manufactured by 3M Co.)

0.05 Parts Di 2-ethylhexyl sebacate (Sansosizer DOA, SP value = 8.5, manufactured by Shin-Nippon Rika Co., Ltd.)

1.13 Parts 1-methyl-2 -pyrrolidone 5.64

Parts Isopropyl alcoh 29.65

Parts

Purified water 41.15

Parts

According to the same manner as that described in Example 1 except for using paint of the above composition, a transparent film for image recording and an image recorded film of this example were produced. The toner image thus obtained was a beautiful transparent image without causing hot offset.

The results obtained by measuring according to the same manner as that described in Example 1 are shown in Table 2 below. In the image recorded film of this example, the color transmission factor can be reduced regardless of the transmission optical density similar to Example 1. Example 5

According to the same manner as that described in Example 1 except for using no di 2-ethylhexyl sebacate, a transparent film for image recording and an image recorded film of this example were produced and then evaluated. The results are shown in Table 4. In the image recorded film of this example, the color transmission factor at the portion having high transmission optical density can be reduced similar to Example 1. However, it was difficult to reduce the color transmission factor at the portion having low transmission optical density.

Table 2

Transmission Color

Example No , Optical density Transmission Factor Example 4 0.98 5.68 0.23 5.15

Example 5 1.04 6.55 0.20 >20.00

Example 6 Styrene-acrylic copolymer latex

[Y-8346 manufactured by Nippon Carbide Co., Ltd: SP value = 9.1, content of styrene units (based on the total weight of the copolymer = 69% by weight)

11.52 Parts Water-dispersed type polyester resin (Byronal MD-1200, manufactured by Toyo Boseki Co., Ltd.; SP value = 10.5)

17.46 Parts Effcoal 214 (antistatic agent, manufactured by Matsumoto Yushi Seika Co., Ltd.)

0.24 Parts Polymethyl methacrylate beads (manufactured by 3M Co.)

0.05 Parts Fluoro-type surfactant (manufactured by 3M Co., FC -170) 0.12 Parts

Di 2-ethylhexyl sebacate (Sansosizer DOA, SP value = 8.5, manufactured by Shin-Nippon Rika Co., Ltd.)

1.18 Parts n-butyl carbitol 1.18 Parts

Isopropyl alcohol 30.49

Parts

Purified water 37.57

Parts

The results obtained by measuring according to the same manner as that described in Example 1 are shown in the following table. In the image recorded film of this example, since a plasticizer was used, and a mixture of a styrene-acrylic copolymer and a polyester resin was used as the polymer of the accepting layer, the color transmission factor can be reduced regardless of the transmission optical density similar to Example 1.

Table 3

Transmission Color Transmission

Example No . Optical density Factor Example 6 1.06 6.51

0.28 3.40

As described above, according to the present invention, there can be provided a transparent film for image recording, comprising a toner accepting layer having improved compatibility with a resin of a wax- containing toner, which is capable of forming a color image having high transparency.

Claims

What is Claimed is:

1. A transparent film for image recording, comprising a transparent substrate and a toner accepting layer provided on at least one major surface of said substrate, said toner accepting layer containing a styrene copolymer, wherein an SP value determined by Small's method of said styrene copolymer is within the range from 8.0 to 9.5.

2. A transparent film for image recording, comprising a transparent substrate and a toner accepting layer provided on at least one major surface of said substrate, said toner accepting layer containing a styrene copolymer and a plasticizer dispersed in said styrene copolymer, wherein an SP value determined by Small's method of said plasticizer is within the range from 8.0 to 9.5.

3. A method of producing an image recorded film, which comprises adhering a wax-containing toner on a surface of a toner accepting layer of a transparent film for image recording of claim 1 or 2 to form a toner image; and pressing said toner image onto said toner accepting layer while heating at a temperature higher than a softening point of said styrene copolymer to embed said toner image into said toner accepting layer, thereby fixing said toner image to said toner accepting layer.