JPS6032059A - Transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a transfer sheet superior in adhesion to a toner, writability with a pencil or especially with an aq. ink, and pencil ersability by providing at least once surface of a base with an overcoat layer composed essentially of a copolymer of styrene/butyl methacrylate/unsatd. org. acid. CONSTITUTION:A proportion of a styrene/butyl methacrylate/unsatd. org. acid type copolymer used for an overcoat layer is not especially limited but the compsn. ratio is preferably in the range of (1-3):(1-3):(1-3). At least one surface of a base is coated with an aq. liquid contg. said copolymer, and dried to form an overcoat layer. A preferable attached amt. of the overcoat layer is <=3g/m<2> in the case of using a nonimpregnable base, and <=5g/m<2> in the case of using an impregnable base through it changes in a little depending on the impregnability of the base.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to improvements in transfer sheets used in electrophotographic transfer systems.

Conventional technology In the electrophotographic transfer method using a PPC copying machine, the toner image formed on the photoreceptor is transferred onto a transfer sheet such as plain paper or matte film (a plastic film with at least one side matted). It is fixed (mainly heat-fixed) and becomes a copy. The performance required of such a transfer sheet is that it has sufficient adhesion to toner so that the toner image can be well fixed, and that it has excellent writability with a pencil or water-based or oil-based ink. Even when erasing with a hard end, it can be erased without causing damage or tearing.

However, none of the conventionally used transfer sheets fully satisfies these required performances.
It is an object of the present invention to provide a transfer sheet that has excellent adhesion to toner, writability with a pencil or especially water-based ink, and eraseability with a pencil.

Structure The transfer sheet of the present invention is characterized in that an overcoat layer containing a styrene/butyl methacrylate/unsaturated organic acid copolymer as a main component is provided on at least one surface of the substrate.

The composition ratio of the styrene/butyl methacrylate/unsaturated organic acid copolymer used in the overcoat layer is not particularly limited, but styrene/butyl methacrylate/unsaturated organic acid = 1 to 3/1 to 3. /1 to about 3 is preferable. If the styrene ratio is less than 1, the strength of the m-film decreases, resulting in poor writing and erasing properties with a pencil, while if it is more than 3, the adhesion to the matting layer or toner tends to be poor. When the dithyl methacrylate ratio is less than 1, the adhesion to toner tends to decrease, and when it is more than 3, the coating film strength tends to decrease. Further, if the organic acid ratio is less than 1, the receptivity to water-based ink and therefore the writing performance with water-based ink will be poor, and if it is more than 3, the water-solubility will increase and there will be a tendency for smearing to occur when adding water-based ink.

Examples of unsaturated organic acids include acrylic acid, methacrylic acid, maleic acid, crotonic acid, and itaconic acid. Further, depending on the method of use, it can be used in the form of a water-soluble or water-insoluble metal salt. Note that the copolymer contains silica,
Fine powders such as glass, clay, titanium oxide, starch, and fused alumina can all be used together.

As the substrate, paper, plastic film, synthetic paper, and those processed with transparent processing, matte processing, surface treatment, etc. can be used.

To make the transfer sheet of the present invention, an aqueous liquid containing styrene/butyl methacrylate/unsaturated organic acid copolymer is coated on at least one surface of the substrate and dried to form a 1-coat layer. good.

The Nm of the overcoat layer is 37//n when a non-impregnable substrate is used (hereinafter, when an impregnable substrate is used, there is a slight difference in the impregnability of the substrate, but it is 511/n?
The following are preferred. If the amount of adhesion is the former, is it 3111n? Above, or in the latter case, if it is 51/ri or higher, the writing performance with a pencil may deteriorate. A transfer sheet with excellent pencil erasability is obtained. In addition, the transfer sheet of the present invention can be used as a drafting sheet for drafting and a sheet for diazo second original drawings when transparent wood is used as the base.

The present invention will be explained below with reference to examples, and all parts and ratios in the examples are based on weight.

Example 1 A matting solution consisting of 90 parts of methyl cellosolzo was applied to both sides of a biaxially stretched polyester film having a thickness of 75 μm using a wire knot so that the dry adhesion amount was 10 II or more. ．． 120(II"'t'1
After drying by heating for a minute, curing was further performed at 1 soc for 5 minutes to produce a matte film. Next, apply oatmocoat solution consisting of 800 parts of earth water and 10 parts of isosolbyl alcohol using smoothing/mer, and dry at 100C for 1 minute to adhere. A transfer sheet was formed by forming an oatsmer coating layer in an amount IIAd.

Example 2 Transfer sheet A was prepared in the same manner as in Example 1, except that a liquid consisting of 1.5 parts of silica powder (average particle size 3 μm), 78.5 parts of water, and 10 parts of isopropyl alcohol was used as the overcoat liquid. did.

Also, this coating liquid T-Hiroko photographic transfer paper (6
A transfer sheet Bf was obtained by coating and drying the coating in the same manner on both sides of plain paper (5g~) to form an adhesion fi2Jl~ Autzmer coat layer.

Adhesion to toner, writability with pencil and water-based ink, and pencil erasability of the transfer sheet of the present invention obtained as described above and the matte film (comparative example) without an overcoat layer in the above example. was tested and the results shown in the table below were obtained.

The test method is as follows.

Adhesion to toner: After forming a toner image on a sample plate using a PPC copying machine and pasting cellophane tape on the image area, peel it off to check whether the image has peeled off or not. If all peeled off, f: 1 and evaluated using a 5-step evaluation method.

Writability: (1) After writing with a 2H pencil and erasing with a plastic eraser, a 5-point evaluation system with 5 being able to write and erase well and 1 being unable to write and erase. do.

(2) When writing with water-based sainben, evaluate on a 5-point scale with 5 being able to write well and 1 being unable to write.

As is clear from the above results, the transfer sheet of the present invention has excellent adhesion to toner and writability with water-based ink compared to comparative products.

Claims (1)

[Claims] 1. A transfer sheet 0 comprising an overcoat layer mainly composed of styrene/butyl methacrylate/unsaturated organic acid copolymer around at least one side of the substrate.