DE19538675A1 - Overhead projector film with peelable printed layer - Google Patents

Abstract

An overhead projector (OHP) film (I) has a transparent base film (A) and a printable layer (B) contg. a binder resin and a filler, which is applied to one or both sides of the base film and is capable of being peeled off the base as a coherent layer. Also claimed is an OHP film for ink-jet printing (II), with layers (A) and (B) as above, in which layer(s) (B) contain(s) a polyvinyl acetal resin and fine particles of an organic polymer with a Mohs hardness of 1-4. Pref. the film has a peel strength of not more than 30 g/cm and a linear transparency of not less than 50%. PREFERRED COMPOSITIONS - In film (I), the wt. ratio of filler to binder resin is 0.01-0.5. The binder resin contains not less than 60 wt.% waterproofed polyvinyl alcohol or not less than 60 wt.% polyvinyl acetal (PV-acetal) resin, and the filler consists of fine particles of PV-acetal resin with a Mohs hardness of 1-4. In film (II), the PV-acetal resin contains polar gps. and pref. consists of an aromatic PV-acetal resin with a degree of acetalisation of 2-40 mole %. The fine polymer particles consist of acrylic resin, pref. with a mean particle dia. of 0.1-3-0 microns

Description

The present invention relates to an overhead projector (OHP) film. In particular, it affects one Overhead projector film which is a translucent support and an ink receiving layer disposed on one or is formed on both sides of the carrier, the Overhead projector (OHP) film ensures that the recorded information can be kept secret and the film can be reused. Also affects the present invention an overhead projector (OHP) film for the inkjet recording excellent in transparency, printability, Water resistance, storage stability, non-stick properties and Is scratch resistance.

Ink recording is generally made using suitable ones Writing utensils such as ballpoint pens, ballpoint pens and Felt pens performed. Recently it was called advanced means of recording ink so-called inkjet recording system (Ink spray recording system) developed.

With the inkjet recording system, ink drops get through various ink-releasing agents and such Ink drops on a recording medium such as e.g. B. paper or deposited a plastic film. There are different known ink dispensing systems such. B. electrostatic Suction systems, systems in which mechanical vibrations or  Displacements using a piezoelectric Elements are applied to the ink, and systems that the Use pressure in the heating and formation of ink is produced.

These inkjet recording systems are very quiet and enable high-speed multi-color recording, a compact design of the printer using this system is used and also allow the Recording on normal paper as well as on special one Printing paper, so these systems are widely used for various types of printing and recording devices such as for example facsimile recorders, printers and Computer terminals is used.

With regard to the cost savings with an inkjet printer and improving the quality of the printed image as well in terms of easy correction and good Inkjet recording will usually look like this executed that the document generated in the computer directly on the overhead projector film (OHP film) is printed. However, the ink absorbency is one Overhead projector film bad because the carrier of the Overhead projector film is generally waterproof. It it is recommended to use a high ink absorption layer Form affinity for the ink on the carrier.

The use of such an ink-receiving layer leads however, to some difficult-to-solve problems. For example in the event that the overhead projector film is on trained a translucent carrier Ink receiving layer contains, the disposal of the used Slide on a serious problem. If an attempt is made Overhead projector film shredded into small pieces by a shredder to shred to keep the recorded information secret  hold, it can happen that appropriate disposal of the Overhead projector film with one on the translucent Carrier-formed ink receiving layer by a Shredder is not possible or that the Overhead projector film in the shredder due to the large thickness the ink-receptive film other than paper jams and stuck. If the thickness of the overhead projector sheet is reduced to better shredder treatment problems arise, such as the waves of Foil during overhead projection and misfeed Foils during printing, causing deterioration of their Manageability leads.

An overhead projector film with a Ink receiving layer on a translucent support no longer after printing on one side can be reused because the carrier is different than paper is transparent, and is such an overhead projector sheet therefore uneconomical.

When the one formed on a translucent support Ink absorption layer could be easily removed, that would be of great economic importance since the after Use removed ink receiving layer easily, for example, by shredder treatment can while the translucent support for Reuse can be offered. If in this case an ink-receiving layer on both sides of one translucent carrier is formed, it is possible an ink record with a single one Execute overhead projector film twice, because after the Use the ink receptive layer on one side again a record on the ink-receiving layer on the other side can be executed.  

The ink receiving layers of conventional ones Overhead projector foils, however, cause the problem that Difficulty in removing and disposing of the used ink receiving layer occur - because of this Ink receiving layer firmly on the translucent support attached; and when trying to force the shift too a small part of it can tear off. In the case of Formation of ink receiving layers on both sides a translucent carrier, there is the problem that the Transparency of the overhead projector film is deteriorated and so there is an indistinct pressure.

In general, an overhead projector sheet for Inkjet recording (hereinafter simply referred to as "OHP- Slide ") meet the following requirements:

• (1) High transparency.
• (2) It is supposed to get the ink inside the Ink absorption layer can absorb quickly, free of Outflow of colors such as B. yellow, purple, teal and Stay black and have high color saturation, and one can reproduce a clear color tone (printability, especially fixing properties).
• (3) You should quickly find the respective ink components absorb even if the ink stains are on the same Level of the recording film for multi-color printing below Use a combination of different inks Colors overlap, should be free of stains on the Recording surface even at a High speed record remain and a sufficient one high ink absorption speed and Have ink absorption capacity (printability).  
• (4) It should be waterproof and resistant to that Then run out of the image or leak the ink even if moisture gets on the film.
• (5) It should not stick to other foils, even when the transparencies are in a feed slot of an inkjet printer stacked on top of each other and should be scratch-resistant, even if the foils rub against each other (non-stick properties - anti-blocking properties).
• (6) Don't let the color fade, even if it is stored after printing (storage stability).

Nevertheless, there is still no OHP film for that Ink jet recording available, all of the above Requirements 1 to 6 met.

As a result of rigorous inventive investigations into Fulfillment of the requirements mentioned above was discovered that by attaching an ink-receiving layer that a Contains binder resin and a filler on at least one Side of a translucent support an OHP film is obtained, which ensures that the recorded Information easily kept secret, and the can be reused without the beneficial To impair the properties of the OHP film. On the basis this discovery has accomplished the invention.

An object of the present invention is to provide an OHP film, with which the confidentiality of the easy to ensure recorded information, and which can be reused without the beneficial To impair the properties of the OHP film.  

Another object of the present invention is Provision of an OHP film for inkjet recording with excellent transparency, printability, Water resistance, storage stability, non-stick properties and Scratch resistance.

To achieve the above goals, a first aspect of the present invention, an OHP film is available put a translucent carrier and a Ink receiving layer comprising a binder resin and a Filler contains and on one or both sides of the Carrier is attached, the ink-receiving layer (s) deducted continuously (continuously) from the carrier can be.

In a second aspect of the present invention, a OHP film made available for inkjet recording, which have a translucent support and at least one An ink receiving layer comprising a polyvinyl acetal resin and fine organic polymer particles with a Mohs hardness contains from 1 to 4 and on one or both sides of the Carrier is attached.

Brief description of the drawing

Fig. 1 is a schematic diagram of an example of an OHP film of the invention.

Detailed description of the invention

The OHP film according to the invention basically comprises a translucent carrier and, applied to one or both sides of this carrier, one or more ink receiving layers. In the OHP film 3 according to the invention, which is shown in FIG. 1, the ink-receiving layers 2 , 2 are applied on both sides of a transparent substrate 1 .

First, the OHP film according to the first aspect of described the present invention. This OHP film is made of a translucent support and one or more Ink receiving layers, which are a binder resin and a Filler included and on one or both sides of the Carrier are attached, these Ink-receiving layer (s) contiguous from the support can be deducted. The OHP film according to the first Aspect of the present invention includes a number of various preferred embodiments.

In a first preferred embodiment of this OHP film is the weight ratio of the binder resin to the filler a range of 0.01 to 0.5 / 1.

In a second preferred embodiment of the OHP film the peel strength of the ink-receiving layer is not more than 30 g / cm.

In a third preferred embodiment of this OHP film are the ink-receiving layers on both sides of the translucent support provided and the linear The transparency of the OHP film is not less than 50%.

The material used for the translucent support 1 is not particularly limited, and any suitable material with suitable translucency can be used. For example, a resin film such as. B. a polyester film, celluloid film or a polyvinyl chloride film can be used. The thickness of the translucent carrier 1 is preferably in a range from 60 to 120 microns, preferably 80 to 100 microns in terms of the linear translucency and the mechanical properties.

A polyvinyl alcohol which has been made waterproof is preferably used as the binder resin for the ink-receiving layers 2 . A mixture of polyvinyl alcohol which has been made waterproof and at least one substance selected from gelatin, polyvinyl pyrrolidone, polyethylene oxide and polyvinyl alcohol, the polyvinyl alcohol content preferably being not less than 60% by weight, more preferably not less than 70% by weight , is also recommended as a binder resin. If the polyvinyl alcohol content in the mixture is less than 60% by weight, it may become difficult to continuously peel off the ink-receiving layer 2 from the transparent support 1 .

A "polyvinyl alcohol that has been made waterproof", refers to any polyvinyl alcohol that is Using acetalization or a crosslinking reaction a water-soluble isocyanate or dimethylolmelamine was made waterproof. Among these is polyvinyl alcohol Polyvinyl acetal is particularly preferred.

Polyvinyl acetal, i.e. H. an acetalized Polyvinyl alcohol resin can be reacted with an aldehyde a polyvinyl alcohol can be obtained. A polyvinyl acetal can also be obtained by using saponification and Acetalization in parallel using each other Polyvinyl acetal as a starting material. Known Processes like a solution process, a precipitation process, a process in a homogeneous system etc. can Acetalization can be used.  

The degree of acetalization of the polyvinyl acetal is one Range from 2 to 40 mol%, preferably 3 to 30 mol%, more preferably 5 to 20 mol%. If the Degree of acetalization is too low, though the ink fixation in the formed ink receiving layer is satisfactory, water resistance tends to be. If the degree of acetalization is too great deteriorates ink fixation tends to be, although the desired Water resistance is achieved. Therefore, an OHP film can be used good ink fixation and high water resistance by using a polyvinyl acetal resin with a Degree of acetalization in a range from 2 to 40 mol% is used.

The "degree of acetalization" is represented by the value which results from the following formula:

A / (A + B + C) × 100 (mol%)

where A is the number of moles contained in the polyvinyl acetal Is acetal groups, B is the mole number of acetyl groups and C is the number of moles of the hydroxyl groups.

The one used in the present invention Polyvinyl acetal resin preferably contains polar groups. Using such a polyvinyl acetal resin an OHP film with an even better ink fixation and achieved higher water resistance. A polyvinyl acetal resin with polar groups can be synthesized for example by using an aldehyde with a polyvinyl alcohol ionic groups in the molecular structure. The Ionic groups can be either cationic or anionic be, but cationic groups are due to existence preferred for many anionic inks.  

The degree of polymerization of the raw material used Polyvinyl alcohol is usually in the range of 300 to 4,500, preferably 500 to 4,500. A higher one Degree of polymerization of the polyvinyl alcohol enables better ink fixation and higher water resistance obtained OHP film. The degree of saponification of the Polyvinyl alcohol is usually in the range of 80.0 to 99.5 mol%, preferably 85.0 to 95.0 mol%. On Polyvinyl alcohol with ionic groups in the molecular structure can be obtained by using a copolymer of vinyl acetate and a monomer with a polar group, e.g. B. a monomer with an amino or ammonium salt group such as Vinyl methyl sulfone, N-methyl acrylamide and tetravalent Connections from being saponified. The polar content Groups of by modifying a monomer with polar Groups obtained as mentioned above polyvinyl alcohol usually in a range from 0.1 to 10 mol%, preferably 1 to 5 mol% with respect to the polar groups containing monomer unit.

As the aldehyde of the starting material, for example aliphatic aldehydes and aromatic aldehydes are used will. Examples of aliphatic aldehydes used as Starting aldehyde can be used close Formaldehyde, acetaldehyde, butylaldehyde, hexylaldehyde, Octylaldehyde and decylaldehyde. Examples of aromatic Aldehydes include benzaldehydes with substituents such as. B. Benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4- Methylbenzaldehyde and chlorobenzaldehyde and phenyl-substituted alkyl aldehydes such as benzaldehyde and β- Phenylpropionaldehyde. Aromatic aldehydes with condensed aromatic rings such as naphthaldehyde, anthraldehyde etc. and aromatic aldehydes with substituents such as hydroxyl groups, Alkoxy groups, amino groups, cyano groups etc. am aromatic ring can also be used. You can too  Aldehydes use the condensed aromatic rings contain such. B. Naphthaldehyde, Anthraldedhyd etc. Aromatic aldehydes are preferred because of their Ink fixation, water resistance and transparency advantageous are.

The OHP films are usually in the form of a stack used or stored in a printer feed slot. Therefore, in the present invention, there is a filler in the Ink containment layer included for the purpose that To make the film surface sufficiently uneven to prevent the stacked OHP films from sticking together cling or for better strippability of the To achieve ink receiving layer.

Fine particles of an organic filler are used Polymer with a Mohs hardness in a range of ordinary 1 to 4, preferably 1 to 3, preferred. As such Fine particles of an organic polymer can e.g. B. Particles of organic polymers such as acrylic resins, Styrene resins, urea-formaldehyde resins, Benzoguanamine resins, silicone resins and fluororesins are used will. Fine particles made of acrylic resins are with regard to good transparency, non-stick properties and scratch resistance of the OHP film obtained is preferred.

Fine silica or titanium oxide particles are too hard and easily create scratches in the foils. Talk particles are sufficiently low in terms of Mohs hardness, but the It creates transparency of the OHP film produced lower.

The shape of the filler particles is preferably so spherical as possible. If the filler particles are spherical, the ink-receiving layer becomes high  Lent transparency and also the probability of Causing scratches on the ink-receiving layers or the translucent carriers of stacked OHP Slides minimized. The diameter of the filler particles is usually in a range of 0.01 to 30 µm, preferably 3 to 30 µm in view of the printability of the formed Ink receptive layer or the non-stick properties of the produced film. If the particle diameter is too large, the roundness of the printed dots is reduced, and if the particle diameter is too small, the obtained OHP films sensitive to adhesion and blocking.

In the present invention, in the Ink receiving layer different types of additives be contained within limits that the effects of not adversely affect the present invention. As Additives can include aqueous ink absorption improvers such as Glycerin, polyethylene glycol, surfactants or the like and agents for Improve ink weather resistance like UV Examples of absorbents, pH adjusting agents or the like be cited.

The ink-receiving layer 2 can be easily formed by applying a coating solution containing the respective components on the surface of a translucent support 1 by a suitable coating method such as painting, roller coating, knife application, etc., and drying the resulting coating. The thickness of the ink-receiving layer after drying is usually in the range of 3 to 20 µm, preferably 5 to 15 µm. If the layer thickness is too small, separation of the organic polymer particles or a reduction in their ink absorption capacity can occur. If the layer thickness is too large, problems arise, such as e.g. B. an extended drying time in the OHP film production process or the corrugation of the OHP film formed.

In the OHP film 3 according to the invention, the ink-receiving layer 2 can be removed continuously (continuously) from the translucent carrier 1 . The term "can be peeled off coherently" means that not less than 50%, preferably not less than 70%, more preferably not less than 90% of the surface of the ink-receiving layer 2 can be coherently and continuously peeled off the support without it to damage. In cases where one or more slits or the like are provided in the ink-receiving layer so that the layer can be divided into small portions along these slits, preferably not less than 50%, more preferably not less than 70%, particularly preferably no less than 90% of the surface of each small section is continuously pulled off the support.

In a first preferred embodiment according to the invention, in order to ensure a continuous peeling of the ink-receiving layer 2 from the translucent carrier 1 , the ratio (weight ratio) of filler to binder resin in the ink-receiving layer 2 is defined as 0.01 to 0.5 / 1. If this weight ratio exceeds 0.5, problems such as rupture of the ink-receiving layer 2 tend to occur when the ink-receiving layer 2 is peeled off from the transparent support 1 , and as a result, it may become impossible to continuously peel off the ink-receiving layer 2 . In addition, if the filler content in the ink receiving layer 2 is too large, the transparency of the OHP film 3 obtained is reduced, although blocking by sticking is less likely to occur. If the filler content is too low, the films adhere to each other, although their transparency is improved.

In the present invention, the peel strength of the Ink receiving layer is set by various means be such. B. by suitable choice of in Ink receptive layer used binder resin, addition of a surfactant for the ink receiving layer or application an easily peelable layer between the Ink receiving layer and the translucent carrier. The easily peelable layer can for example be a thin one Layer of a surfactant alone, a resin layer with one Surfactant or a coating layer of a wax like Be polyoxyethylene. In case of using a surfactant one with antistatic properties is preferred. If a resin layer containing a surfactant is applied, is preferably a surfactant in an amount of 1 to 20 wt .-%, based on the binder resin, contained therein.

In a second preferred embodiment according to the invention, in order to ensure and facilitate the continuous peeling of the ink-receiving layer 2 from the translucent carrier 1, the peel strength of the ink-receiving layer 2 is usually not more than 30 g / cm, preferably not more than 20 g / cm, more preferably not more than 15 g / cm set. If the peel strength exceeds 30 g / cm, it may become difficult to peel off the ink receiving layer 2 . The lower limit of the peel strength of the ink-receiving layer 2 in the present invention is usually 2 g / cm.

Further, in this second preferred embodiment of the present invention, the elastic modulus of the ink receiving layer 2 is preferably not less than 1 × 10⁴ kg / cm². Such an ink receiving layer can be realized, for example, by using a polyvinyl acetal resin as a binder resin and adjusting the filler-to-binder resin weight ratio so that it falls in the range of 0.01 to 0.3. The lower limit of the elastic modulus in the ink receiving layer 2 is usually 1 × 10⁴ kg / cm².

In a third preferred embodiment of the invention, the ink-receiving layers 2 are applied on both sides of the light-sensitive support 1 and the OHP film obtained has a linear light transmission of not less than 50%, preferably not less than 70%. The OHP film with such a high linear transmittance can produce a high contrast between the recorded and unrecorded parts of the image when the recorded image is viewed by overhead projection, and enables an image to be obtained which is clear and flat even in color printing. If the linear light transmission of the OHP film is less than 50%, the picture is dark and the color is also barely recognizable.

The linear light transmittance T (%) mentioned is that Ratio of transmittance Y of linear light that has passed through the OHP film to the permeability Y₀ of linear light in the absence of the measured object (Blank test) (if white light is vertical to the OHP film is applied) and results from the following equation:

T = Y / Y₀ × 100

wherein
T = linear light transmission,
Y = value of the sample, and
Y₀ = blank value.

The preferred linear as defined above Transparency of the OHP film can be realized by the type and thickness of the translucent support, Art and amount of binder resin, filler and other additives in the ink receiving layer, the thickness of the Ink receiving layers and other parameters suitably chooses. For example, the weight ratio of filler to Binder resin, although depending on the filler Particle size can be variable, preferably so set to fall in a range of 0.01 to 0.1, so that the linear light transmission of the generated OHP Film is not less than 50%. Also the thickness any ink-receiving layer after drying, though variable depending on the type of used Binder resin, preferably in a range of 1 to 10 microns set.

In the OHP film according to the invention, the Ink receiving layer on which the recording is made was removed from the translucent support and the separated ink-receiving layer can easily, for example through a shredder, so that the OHP film according to the invention easily meets the requirement of Security of recorded information.

In addition, the translucent support after separation the ink receiving layer as OHP film for copying purposes be reused. Such carriers can be collected and with ink receiving layers newly formed thereon can be reused as OHP films according to the invention.

In the present invention, the one mentioned Ink receiving layer on both sides of one photosensitive carrier are provided and so an OHP Slide will be made available to the two passes  can be subjected to ink recording, the first recording pass with the ink receiving layer on one side of the carrier and after separating it used up the second pass with the shift Ink receiving layer on the opposite side is performed. In this case too, it is possible Guarantee the confidentiality of the recorded information, for example, the used ink receiving layers be disposed of by a shredder; after separation of the Ink receiving layers can be used as OHP film for the carrier ordinary copying purposes can be reused.

It is noteworthy that the OHP film according to the invention in which the weight ratio of filler to binder resin in one Range is 0.01 to 0.5, a contiguous Peel off the ink-receiving layer from the translucent Carriers allowed with certainty.

In an OHP film according to the invention, in which the Peel strength of the ink-receiving layer no more than Is 30 g / cm, a coherent subtraction of the Ink receiving layer from the translucent carrier safely and just run.

Furthermore, with an OHP film according to the invention, the linear light transmission is not less than 50%, although ink-receiving layers on both sides of the translucent carrier can be provided, a high Contrast between the recorded and achieved unrecorded parts when the recorded Image is observed as an OHP image, because of the high transparency of the film, and the image obtained is clear and even, even with color printing.  

Now the OHP film is used for an inkjet recording the second aspect of the present invention is explained. The OHP film includes one translucent support and an ink-receiving layer which a polyvinyl acetal resin and fine particles from one contains organic polymer with a Mohs hardness of 1 to 4. The ink-receiving layer is on one or both sides provided by the wearer. In a preferred embodiment This film is a water soluble acrylic resin in Used in combination with a polyvinyl acetal resin. The for used the OHP film for ink spray recording Materials such as B. the polyvinyl acetal resin, the organic polymer particles with a Mohs hardness of 1 to 4 and the water-soluble acrylic resin and other conditions such as e.g. B. the ratios of these components are the same as in the production of the OHP film according to the first aspect of above invention described above.

The OHP film for inkjet recording according to the second Aspect of the present invention is its printability remarkably improved while having other properties maintains in that a polyvinyl acetal resin for the ink receiving layer is used. It can also Adhesion between the translucent support and the Ink-receiving layer by using a water-soluble Acrylic resin for the ink receiving layer are reinforced.

Water-soluble acrylic resins form a waterproof film drying and serve to strengthen the adhesion between the translucent carrier and the ink-receiving layer, thereby counteracting the non-stick properties of the film improve other slides.

Any resin or can be used as the water-soluble acrylic resin Resin compositions from water soluble polymers of  Acrylic esters are used, for example Acrylic ester polymers (polyacrylic esters) obtained from one Esterification of acrylic acids or acrylic chlorides and alcohols or a transesterification reaction of methyl acrylate. Water-soluble acrylic resins are available as an aqueous solution or aqueous emulsion available.

The ratio (by weight) of polyvinyl alcohol, the was made waterproof (such as polyvinyl acetal, etc.) to water-soluble acrylic resin is preferably in one range from 9: 1 to 3: 7, more preferably 6: 4 to 4: 6. If the Proportion of the water-soluble acrylic resin is too large, reduces the ink absorption capacity of the Ink receiving layer and the drying of the ink is done thereby delayed. On the other hand, if the Polyvinyl acetal content becomes too large, the strength of the Ink receiving layer deteriorated. So through Formation of an ink receiving layer by mixing two specific resins in a specific ratio an OHP film for inkjet recording can be obtained excellent especially in their printability, Water resistance and adhesion is.

The OHP film according to the invention using a Polyvinyl acetal resin for the ink receiving layer is also excellent in water resistance compared to one OHP film for which a water-soluble resin like Polyvinyl alcohol or carboxymethyl cellulose for the Ink receiving layer is used, and has a better one Ink absorbency and color density stability in the Course of time after printing compared to one OHP film, in which the water-soluble resin in the Ink-receiving layer has been crosslinked. Besides, that is OHP film according to the invention, the fine particles from a organic polymer with a Mohs hardness of 1 to 4 in  Contains ink receiving layer, excellent in transparency and scratch resistance compared to an OHP film that fine silica particles or the like in the ink receiving layer contains. The scratch resistance is an important factor for that safe feeding of OHP foils into a printer.

An OHP film with improved fixing properties and Water resistance can be increased by using a Polyvinyl acetal resin with polar groups or one aromatic polyvinyl acetal resin can be achieved. In particular, the use of a polyvinyl acetal resin with a degree of acetalization of 2 to 40 mol% an OHP Provide film that has non-stick properties and the scratch resistance is further improved.

As inks for inkjet printing on the OHP films according to the invention can be used ordinary inks made from a water-soluble dye, a Wetting agent, a dye solubilizing agent, Water and a water-miscible organic solvent be used.

Examples

The present invention is further enhanced by the following Examples and comparative examples are explained, the only to are given for illustrative purposes and not the invention should limit. The evaluation of the OHP films obtained was carried out in the following way:

(1) Peelability

The ink receptive layer of each OHP film sample was dated End pulled off the translucent carrier. The Peelability of the sample was indicated by O if  the pulling could be carried out coherently without damage the ink-receiving layer, and X if the Ink absorption layer broke and no less than 50% of that Surface of the ink-receiving layer on the carrier stayed behind.

(2) transparency

Each OHP film sample was printed so that each printed Letter was within the area of a square centimeter, and project the image through an overhead projector. The Result was labeled O when the projected Letters could be read, and with X if the Letters were illegible.

(3) peel strength

Each of the OHP films obtained was 15 cm long and 1 cm long cut wide strips and the force (mean) that to peel the ink-receiving layer from the support a length of 10 cm in the longitudinal direction was required, using a Tensilon UTM-III-100 meter (manufactured by Orientecs Co., Ltd.).

(4) Draw characteristics of the ink receiving layer

The modulus of elasticity of the peeled ink receiving layer was measured according to the method of JIS K-7113.

(5) Linear light transmission

Measured by a self-writing spectrophotometer U-3500 (manufactured by Hitachi Corp.).  

(6) Quality of the projected image

4 mm × 4 mm letters were printed on each OHP film and projected these letters through an overhead projector and watched. The projected image quality was checked with O rated if the letters were clearly projected and with X if the letters were dark and barely legible.

(7) transparency

The transparency of the OHP film was before printing determined by a measuring instrument for the absorption of transmitted light called Macbeth TR-927 (manufactured by Macbeth, a Kollmorgen company Corp.) was used.

(8) Printability

Each sample OHP film was printed with an inkjet printer and the printed dots under a stereo microscope observed. The grade O was given when the printed Dots were circular and the ink didn't leak and that Image was clear even when using the record of inks of different colors, each other overlapped, was executed. The grade X was for others Award results.

(9) Water resistance

Each OHP film was made using an inkjet printer printed and one hour after printing the film in Tap water immersed for 1 min and then pulled out. Of the State of the ink image immediately after pulling out the Film was observed visually. The grade was given if the film is perfectly in its original state during drying  accepted again. The grade O was given when the film in the essentially returned to its original condition. The grade ∆ was awarded when the ink was partially washed out and the ink receiving layer was swollen. The grade × was awarded when the ink-receiving layer ran out.

(10) Non-stick properties

Two OHP films were stacked on top of each other Ink receiving layers placed down and under the Conditions of 60 ° C and 90% R.F. 20 days under one Weight of 100 g left (the contact surface with the OHP film was 5 cm²). After that, the liability state observed between the two slides. The grade × was forgiven if the two foils stuck together, the mark ∆ was given when the slides a little clinging together, the grade ○ was given if none Liability could be determined.

(11) Scratch resistance

An OHP film was placed on a glass plate with the Ink receiving layer fixed up and then another OHP film on it with its ink absorption layer facing down put on and then apply a weight of 100 g (Contact area with the film 5 cm²) the glass plate in rubbing along the film parallel to the longitudinal direction the film is moved at a speed of 160 mm / min. The degree of scratches on the ink-receiving layer were observed and the scratch resistance like is rated as follows: The mark × was awarded if scratches were found could be recognized with the naked eye. The grade ○ was forgiven if no scratches could be detected.  

(12) Storage stability

A four-color print was made with each OHP film Inkjet printers run and the dot density right after the Print and after 30 days by a Macbeth TR-927 measured, and so the time change of Point density determined. Of the four colors, the one whose point density had decreased the most after 30 days, selected, and the percentage change in (%), based on the dot density (100) of this color Printing, specified.

example 1

2 parts by weight of high molecular acrylic resin particles (MR-13G, manufactured by Soken Kagaku Co., Ltd .; middle Particle diameter 13 µm) were in 1000 parts by weight Polyvinyl acetal resin (KX-1 manufactured by Sekisui Chemical Co., Ltd., solids content 8%, degree of acetalization: 8 mol%) dissolved and through a valve homogenizer (manufactured by APV Gaulin Inc.) under a pressure of 200 kg / cm² dispersed so as to be a coating solution to manufacture. This coating solution was on both sides a polyethylene terephthalate film (T600W07 manufactured by Diafoil Hoechst Co., Ltd.) to a coating thickness Drying of 7 microns applied and then at 120 ° C for 10 min Obtaining an OHP film dried. This OHP film was in terms of peelability, peel strength and Tension characteristics (modulus of elasticity) of the Ink absorption layers evaluated. The results are in Table 1 shown.

The ink-receiving layers of this OHP film could easily be subtracted so that after printing image-printed ink-receiving layer to be disposed of alone  could while the ink receiving layer on the opposite side for use for another Print run remained. The one for the second press run ink-receiving layer used could also easily be subtracted, and the translucent support that after Peel off the ink-receiving layers from both sides remained, could be printed with a copier and could be used as an ordinary OHP film.

Comparative Example 1

The same procedure as in Example 1 was carried out except that a polyethylene terephthalate film with a Adhesive layer (Roomier 100 Q 80D, manufactured by Torey Industries Inc.) was used and so an OHP film obtained and this film in the same way as in Example 1 evaluated. The results are shown in Table 1.

The ink receiving layer of this OHP film could not be clear be peeled off and so this film was not reusable.

Table 1

Example 2

5 parts by weight of cross-linked high-molecular acrylic resin particles (BR-89, manufactured by Mitsubishi Rayon Co., Ltd .; middle Particle diameter: 20 µm) were used as filler in 1,000 parts by weight of polyvinyl acetal resin (KX-1 manufactured by Sekisui Chemical Co., Ltd .; 8% solution; Degree of acetalization: 8 mol%) dissolved and by a Valve homogenizer (manufactured by APV Gaulin Inc.) at dispersed a pressure of 200 kg / cm² and so one Coating solution made. This coating solution was on both sides of a polyethylene terephthalate film (T600, manufactured by Diafoil Hoechst Co., Ltd.) on a Coating thickness applied after drying of 7 microns and then dried at 120 ° C for 10 min and so an OHP film receive. The peelability and transparency of this OHP film were checked. The results are shown in Table 2.

The ink-receiving layers of this OHP film could easily be subtracted so that after printing discarded image-printed ink-receiving layers alone could become. Another print run could be done with this OHP film are run, the ink receiving layer was used on the opposite side. This for ink-receiving layer used in the second pass could also be easily removed and that after Peeling off the ink-receiving layers remaining translucent carrier could be done with a copying machine print and could as ordinary OHP film be reused.  

Comparative Example 2

The procedure of Example 2 was repeated except that 1,000 parts by weight of polyvinyl alcohol (KH-17 manufactured by Nippon Synthetic Chemical Co., Ltd .; 10% aqueous solution) and 500 parts by weight of polyvinylpyrrolidone (K-15 manufactured by GAF Corp.) as binder resin and 540 parts by weight of colloidal Silica (Snowtex C, manufactured by Nissan Chemical Industry Co., Ltd .; 20% aqueous solution) used as filler were obtained, and thus an OHP film. This OHP film was subjected to the same evaluation tests as in Example 2. The Results are given in Table 2. The Ink-receiving layers of this OHP film could not deducted coherently and so this was film not reusable.

Comparative Example 3

The same procedure as in Example 2 was carried out, except that 1,000 parts by weight of polyvinyl alcohol ((KH-17 from Nippon Synthetic Chemical Co., Ltd .; 10% aqueous Solution) as binder resin and 330 parts by weight of colloidal silica (Snowtex C, manufactured by Nissan Chemical Industry Co., Ltd .; 20% aqueous solution) were used as filler, and so get an OHP film. The results of the Evaluation tests were the same as in Example 2. The Results are shown in Table 2. The Ink-receiving layers of this OHP film could not be pulled together and the film was thus not reusable.  

Table 2

Example 3

The same procedure as in Example 2 was carried out, except that the coating solution was applied so that the thickness the ink-receiving layers after drying 5 µm each Layer was so that an OHP film was obtained, and this film became linear in terms of its peelability Translucency and projected image quality evaluated. The results are shown in Table 3. The Letters printed on this OHP film could clear be projected. The ink-receiving layers could also this film can be pulled off in a coherent manner so that after printing, the one printed with letters Ink absorption layer could be disposed of alone, which the Ink receiving layer on the opposite side Left behind for another press run. The used for the second press run Ink receiving layer could also be slightly cohesive be subtracted and that after subtracting this The film that remained in the ink-receiving layers could be used copying an ordinary copying machine and could as OHP film can be reused.  

Comparative Example 4

The same procedure as in Example 3 was carried out, except that high molecular acrylic resin particles in an amount of 12 parts by weight (15 parts by weight per 100 parts by weight Resin solids) were added and so an OHP film was obtained, and this film in the same way as in Example 3 evaluated. The results are shown in Table 3 shown. The linear light transmission of this OHP film was as low as 33% so the projected letters were dark and barely legible. Besides, they were Ink receiving layers of low strength and could not be deducted contiguously, so that the film was not reusable.

Table 3

Example 4

2 kg of water became 240 g of a polyvinyl alcohol (Degree of polymerization 1600 and degree of saponification 90 mol%) given and then warmed. After solving the The solution was cooled to polyvinyl alcohol. Then were 120 g of 35% by weight hydrochloric acid and 50 g of phenylacetaldehyde Solution given and reacted at 10 ° C for 5 h. That so synthesized polyvinylphenylacetal resin had one Degree of acetalization of 15 mol%.  

This resin was made in a 1: 1 mixed solvent Dissolved water and isopropyl alcohol. 96 parts by weight (calculated as solids of Polyvinylphenylacetaldehyde resin) of the resulting solution 4 parts by weight of acrylic resin particles (BR-89, were produced from Mitsubishi Rayon Co., Ltd .; average particle diameter 20 µm; Mohs hardness: 2.5) followed by one Solution step and then a dispersing step by a Valve homogenizer (manufactured by APV Gaulin Inc.) at a pressure of 200 kg / cm², so that a coating solution was produced. This coating solution was applied to one Polyethylene terephthalate film (T-600 manufactured by Diafoil Hoechst Co., Ltd., corona-treated film) and dried at 120 ° C for 10 min so that a Ink receiving layer with a thickness after drying 7 microns formed and thereby an OHP film was obtained. Transparency, printability, water resistance, Non-stick properties, scratch resistance and storage stability this OHP film was examined. The results are in Table 4 shown. The recording on this OHP slide was made using a 560-C color inkjet printer (manufactured by Hewlett Packard Ltd.).

Example 5

The same procedure as in Example 4 was carried out, except that butyraldehyde as aldehyde in the synthesis of the Polyvinyl acetal resin was used, and so an OHP film obtained and this film in the same way as in Example 4 evaluated. The results are shown in Table 4.  

Example 6

The same procedure as in Example 4 was carried out, except that polystyrene resin particles (GSP-70C, manufactured by Soken Kagaku Co., Ltd .; average particle diameter: 20 µm; Mohs Hardness: 2.5) when organic polymer particles were used and so get an OHP film. The evaluation results of this OHP film are shown in Table 4.

Example 7

The same procedure as in Example 4 was carried out, except that butyraldehyde as aldehyde in the synthesis of the Polyvinyl acetal resin was used and that polystyrene resin Particles (GSP-70C manufactured by Soken Kagaku Co., Ltd .; average particle diameter: 20 µm; Mohs hardness: 2.5) as organic polymer particles were used so that a OHP film was obtained, and this film was as in Example 4 evaluated. The results are shown in Table 4 shown.

Example 8

The same procedure as in Example 4 was carried out, except that the acrylic resin particles in an amount of 0.5 parts by weight were added, and so obtained an OHP film and as in Example 4 evaluated. The results are shown in Table 4 shown.  

Table 4

Table 4 (continued)

Example 9

2 kg of water were added to 240 g of polyvinyl alcohol with a Degree of polymerization of 1,600 and a degree of saponification of 90 mol% and a content of 2 mol% of an ammonium base  given by N-methyl acrylamide and heated. After the dissolution of the Polyvinyl alcohol, the solution was cooled and then 120 g 35% by weight hydrochloric acid and 50 g of phenylacetaldehyde for the solution given and reacted at 10 ° C for 5 h. The so synthesized Polyvinylphenylacetoacetal resin had a degree of acetatization of 15 mole%.

This resin was made in a 1: 1 mixed solvent Dissolved water and isopropyl alcohol. 96 parts by weight (calculated as solids polyvinylphenylacetoacetal resin) 4 parts by weight of acrylic resin particles (BR-89, manufactured by Mitsubishi Rayon Co. Ltd .; middle Particle diameter: 20 µm, Mohs hardness: 2.5) and solved, followed by dispersion by a Valve homogenizer (manufactured by APV Gaulin, Inc.) at a pressure of 200 kg / cm², so that a coating solution was produced. This coating solution was made using a Doctor knife (bar) on a polyethylene terephthalate film applied (T-600, manufactured by Diafoil Hoechst Co., Ltd., corona-treated film) and at 120 ° C for 10 min dried so that an ink receiving layer with a thickness of 7 µm (after drying) and thus an OHP Foil was obtained. Transparency, printability, Water resistance, non-stick properties, scratch resistance and Storage stability of this OHP film was examined and the Results are shown in Table 5.

Example 10

The OHP film of Example 9 was under in the same manner Using a 660-C Color Inkjet Printer (manufactured by Hewlett Packard Ltd.) evaluated. The results are in Table 5 shown.  

Example 11

The same procedure as in Example 9 was carried out, except that a polyvinyl alcohol with imported vinyl methyl sulfone Groups instead of the ammonium salt of N-methyl acrylamide was used, and so obtained an OHP film and the film as evaluated in Example 9. The results are in Table 5 shown. A 660-C color inkjet printer (manufactured from Hewlett Packard Ltd.) was used for printing.

Example 12

The same procedure as in Example 9 was carried out, except that butyraldehyde as aldehyde in the synthesis of the modified polyvinyl acetal resin was used, and so obtained an OHP film and evaluated as in Example 9. The results are shown in Table 5. A color inkjet Printer 660-C (manufactured by Hewlett Packard Ltd.) used for printing.

Example 13

The same procedure as in Example 9 was carried out, except that polystyrene resin particles (GSP-70C, manufactured by Soken Kagaku Co., Ltd .; average particle diameter: 20 µm; Mohs Hardness: 2.5) when organic polymer particles were used and so obtained an OHP film and this film according to the example 9 evaluated. The results are shown in Table 5. A 660-C color inkjet printer (manufactured by Hewlett Packard Ltd.) was used for printing.

Example 14

The OHP film of Example 6 was made using a 660-C color inkjet printer (manufactured by Hewlett Packard  Ltd.) evaluated. The results are shown in Table 5 shown.

Example 15

The same procedure as in Example 9 was carried out, except that the acrylic resin particles in an amount of 0.5 parts by weight were added, and so obtained an OHP film and this Film evaluated in the same way as in Example 9. The Results are shown in Table 5. A color inkjet Printer 660-C (manufactured by Hewlett Packard Ltd.) used for printing.  

Table 5

Table 5 (continued)

Tables 4 and 5 clearly show that the OHP films produced according to the invention for which a Polyvinyl acetal resin and specific organic polymer Particles with a Mohs hardness of 1 to 4 for the Ink receiving layers have been used, excellent in all essential properties such as transparency, Printability, water resistance, non-stick properties, Scratch resistance and storage stability were.

Also, as can be seen from Table 5, it is clear that if a Polyvinyl acetal resin with polar groups was used Ink compatibility and especially water resistance be further improved.

Example 16

2 kg of water were added to 240 g of polyvinyl alcohol with a Degree of polymerization of 1,600 and a degree of saponification of Given 90 mol% and the solution heated. After the dissolution of the Polyvinyl alcohol, the solution was cooled and then 120 g  35% by weight hydrochloric acid and 50 g of phenylacetaldehyde were added and the content at 10 ° C for 5 h implemented. The so synthesized Polyvinylphenylacetoacetal resin had one Degree of acetalization of 15 mol%.

This resin was made in a 1: 1 mixed solvent Dissolved water and isopropyl alcohol. 58.8 parts by weight (calculated as solids polyvinylphenylacetoacetal resin) of this solution and 39.2 parts by weight of a solution of one Polyacrylic ester resin (Julimer AT-613, manufactured by Nippon Junyaku Co., Ltd .; aqueous solution with a solids content of 25%) were mixed (Polyvinylphenylacetal resin / polyacrylic ester resin Weight ratio = 6: 4). To this mixed solution 2.0 parts by weight of acrylic resin particles (BR-89, manufactured by Mitsubishi Rayon Co., Ltd.); average particle diameter: 20 µm) and dissolved, followed by dispersion through a Valve homogenizer (manufactured by APV Gaulin Inc.) at a pressure of 200 kg / cm² and thus a coating solution manufactured.

This coating solution was made on a polyethylene terephthalate Film (T-600, manufactured by Diafoil Hoechst Co., Ltd., corona-treated film) applied by brushing and such an ink receiving layer with a thickness (after drying) of 12 µm, so that an OHP film was obtained. The transparency of this OHP film was Printability, water resistance, non-stick properties, Adhesion and storage stability tested. The results are shown in Table 6. A 560-C color inkjet printer (manufactured by Hewlett Packard Ltd.) was recorded used on the OHP film.  

Example 17

The same procedure as in Example 16 was carried out, except that butyraldehyde as aldehyde in the synthesis of the Polyvinyl acetal resin used to obtain the OHP film and the film was made in the same manner as in Example 16 evaluated. The results are shown in Table 6.

Example 18

The same procedure as in Example 16 was carried out, except that the weight ratio of Polyvinyl acetal resin / polyacrylic ester resin changed to 4: 6 was obtained, and so an OHP film and this film as in Example 16 evaluated. The results are shown in Table 6 shown.

Example 19

The same procedure as in Example 16 was carried out, except that the weight ratio of Polyvinyl acetal resin / polyacrylic ester resin changed to 9: 1 was obtained, and so an OHP film and this film as in Example 16 evaluated. The results are shown in Table 6 shown.

Example 20

The same procedure as in Example 16 was carried out, except that the weight ratio of Polyvinyl acetal resin / polyacrylic ester resin changed to 2: 8 was obtained, and so an OHP film and this film as in Example 16 evaluated. The results are shown in Table 6 shown.  

Example 21} 0

The same procedure as in Example 16 was carried out, except that silica particles were used as a filler and so receive an OHP film and this film as in Example 16 evaluated. The results are shown in Table 6.

Table 6

Table 6 (continued)

Claims (15)

1. overhead projector film, comprising a translucent carrier and a Ink receiving layer, which is a binder resin and a Filler contains and on one or both sides of the Carrier is attached, this Ink receiving layer (s) contiguous to this Carrier can be deducted. 2. overhead projector film according to claim 1, characterized, that the peel strength of the ink-receiving layer is not is more than 30 g / cm. 3. overhead projector film according to claim 1 or 2, characterized, that the weight ratio of filler to binder resin Is 0.01 to 0.5. 4. overhead projector screen according to at least one of the previous claims, characterized, that the linear light transmission of the Overhead projector film is not less than 50%. 5. overhead projector screen according to at least one of the previous claims, characterized,  that the binder resin is composed of not less than 60% by weight Polyvinyl alcohol exists, which is made waterproof has been. 6. overhead projector screen according to at least one of the previous claims, characterized, that the binder resin is made of not less than 60% by weight of a Polyvinyl acetal resin exists. 7. overhead projector screen according to at least one of the previous claims, characterized, that the filler consists of fine particles from a organic polymer with a Mohs hardness of 1 to 4 consists. 8. overhead projector film for inkjet printing, comprising a translucent support and an ink-receiving layer that is a polyvinyl acetal resin and fine particles of an organic polymer with contains a Mohs hardness of 1 to 4 and on one or is attached to both sides of the carrier. 9. overhead projector film according to claim 8, characterized, that the polyvinyl acetal resin with a polyvinyl acetal polar groups. 10. overhead projector film according to claim 8 or 9, characterized, that the polyvinyl acetal resin is aromatic Is polyvinyl acetal resin. 11. overhead projector film according to claim 8 to 10,  characterized, that the degree of acetalization of the polyvinyl acetal resin 2 is up to 40 mol%. 12. overhead projector film according to claim 8 to 11, characterized, that the fine organic polymer particles are particles of an acrylic resin. 13. overhead projector film according to claim 8 to 12, characterized, that the average diameter of the fine organic Polymer particles is 0.1 to 30 microns. 14. overhead projector film according to claim 8 to 13, characterized, that the ink-receiving layer is a water-soluble Contains acrylic resin. 15. overhead projector film according to claim 14, characterized, that the weight ratio of polyvinyl acetal resin too water-soluble acrylic resin is 9: 1 to 3: 7.