Manufacture of carbonless reproduction paper

Abstract

 A developer sheet for carbonless reproduction paper having a phenolic resin developer comprising cationic starch as an anti-yellowing adhesive or binder. Desirably the developer further comprises an activated clay.

Description

OUTLINE

[0001] 

(1) The present invention relates to a method for manufacturing carbonless reproduction paper which features the following. That is; relating to such a developer sheet for carbonless reproduction paper, that as developer it uses a phenolic resin developer that as adhesive uses cationic starch.

(2) The present invention further relates to a method for manufacturing carbonless reproduction paper as described in point 1 which has the following feature. That is; the phenolic resin developer comprises activated clay.

(3) The present invention further relates to a method for manufacturing carbonless reproduction paper as described in point 1 which has the following feature. That is; it uses more than 50 wt. parts of cationic starch as against 100 wt. parts of phenolic resin.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0002] The present invention relates to a method for manufacturing developer sheet for carbonless reproduction paper, further detailed to a method for manufacturing developer sheet, which features that phenolic resin is used, or a system that combinedly uses phenolic resin and activated clay, and, as adhesive, cationic starch.

[0003] The so-called carbonless paper has been publicly known among those concerned, and as described for example, in the U.S. Patent Specification Nos. 2 712 507, 2 730 465, 2 730457 etc., it utilizes both micro-capsules containing solution of organic solvent of colorless organic compound (hereinafter referred to as coupler) having electron donating property, adsorbable property and coloring reactive property and electron accepting reactive adsorbing substance (hereinafter referred to as developer). Hitherto as method for micro-encapsulation it has adopted the coacervation method, the interfacial polymerization method, the in situ method, etc., and as coupler malachite green lactone, crystal violet lactone, benzoyl leuco methylene blue, rhodamine B lactone, 3-dialkylamino-7-dialkyl acyl fluorane, 3-methyl-2, 2-spiropy (benzo-(f)-chromen) etc. have so far been used, and further as the aforementioned developer generally there are a method which uses solid acids such as acid clay, activated clay, attapulgite, zeolite, bentonite and so on and a method which uses various kinds of phenolic resin such as para-tertiary butyl phenolic resin, paraphenyl phenolic resin and so on, organic acid compounds such as succinic acid, tannic acid, maloic acid, gallic acid and so on, further aromatic carboxylic acid such as benzoic acid, salicylic acid, substituted salicylic acid, naphthoeic acid, diphenic acid and so on or metallic compounds of these.

[0004] Such a kind of developer sheet that uses phenolic resin which is an organic developer out of these developers has merits that it shows good color forming property, and excellent color-fading property, and generally it has been widely used, but at the same time it has such defects that it shows marked yellowing due to sunlight irradiation and adsorption of nitrogen oxidant present in the atmospheric air indoors. Moreover, in recent years as described in the Patent Publication No. SHO 50-17888 phenolic resin and solid acid, particularly activated clay have come to be combinedly used, but in such a case such a kind of developer sheet shows such a defect in that it is most likely to turn out markedly yellowing, and therefore the demand for improvement has been urgently desired among those concerned.

[0005] In order to improve these defects the use of pigments such as zinc oxide, titanium oxide, aluminum hydroxide and additives such as ultraviolet ray absorber, oxidation preventive and so on has been well known, but still found insufficient. Hitherto, as adhesive for developer sheet for carbonless reproduction paper water soluble adhesive such as starch, polyvinyl alcohol, gum arabic and so on and latexes such as styrene butadiene latex, acryl latex and so on have been well known among those concerned. Besides, as starch it has been revealed in Japanese Patent Publication Nos. SHO 41-16822, SHO 46-4615, SHO 47-51736, SHO 50-16968 and SHO 50-16969, SHO 53-91267, and further as described in the Patent Publication Nos. SHO 48-4053, SHO 49-10856, SHO 50-102413 and SHO 53-95704 denatured starch such as starch oxide, enzeme starch, urea starch phosphate, alkylated starch and so on, and as described in the Patent Publication No. SHO 42-20143 etherized starch and as described in the Patent Disclosure No. SHO 53-111809 esterized starch phosphate and the like have been publicly known.

[0006] With respect to these starches they show little defect in terms of adhesive power and coating suitability, but for the purpose of improving the defect of yellowing inherent in said developer sheet in attempts to study more on it no efforts have been made, and in reality it has been found from the studies made by the inventors of the present invention that these have hardly any effect for inhibiting yellowing phenomenon. As the result of various studies so far conducted the inventors of the present invention have found that by using cationic starch which hitherto has not been used for developer sheet yellowing phenomenon due to sunlight irradiation and adsorption of nitrogen oxidant in the atmospheric air indoors of said developer sheet can be lessened and accomplished the present invention.

[0007] Many cationic starches have been put on sale in the market for internally containing, sizing press and coating for the purpose of paper making. Concerning the method for manufacturing these and its use they have been already revealed for example in the Roy L. Whistier. F. Paschall "Starch Chemistry and Technology" Vol. 2 Academic Press (U.S.A.), 1967 p. 403-420. The amount of cationic starch for the present invention is more than 50 wt. parts as against 100 wt. parts of phenolic resin, particularly preferably 80 - 150 wt. parts. In case of any of singular use, combined use with latex, combined use of starch oxide and latex and combined use with starch oxide cationic starches of the present invention can be effected in any way. As phenolic resin used for the present invention there are para-phenyl phenolic resin, para-tertiary butyl phenolic resin, para-octyl phenolic resin, para-chlor phenolic resin, para-cumyl phenolic resin, its metal salts and so on, and particularly among them para-phenyl phenolic resin has high coupling density and is favorable. So-called activated clay is so constituted that acid clay or clay, similar to it is treated with mineral acid in such a way that alumina, iron and any other basic component soluble in acid may be deposited until its surface area shows more than 200 m²/g, and in case of activated clay used for the present invention it little matters whether metal salts of zinc, magnesium are admixed with it.

[0008] As pigments for the present invention any suitable amount of inorganic pigment such as calcium carbonate, zinc oxide, kaolin, clay, activated clay and so forth and organic pigment such as urea-formalin resin and so on are used. As latex that can be combinedly used for the present invention styrene butadiene latex, vinyl acetate latex, acryl latex and so on can be used, but the present invention may not particularly be restricted to these only. Cationic starch for the present invention is dispersed in publicly known dispersant, additive, the aforementioned pigment, phenolic resin and latex so that it may be mixed until coating liquid is prepared and then coated on base material such as paper in such a way that developer sheet can be prepared. Now, referring to the concrete Examples.the present invention will be concretely described as follows. Besides, as coupler coated paper to sheet for carbonless reproduction paper put on sale in the market "Mitsubishi NCR paper top-40" is used.

(MANUFACTURE OF DEVELOPER SHEET FOR CARBONLESS REPRODUCTION PAPER)

EXAMPLE 1:

[0009] After 50 parts of kaolin (Ultra-white-90, manufactured by Engel Hard Corp.) and 50 parts of calcium carbonate (PC, manufactured by Shiraishi Kogyo Co., Ltd.) are gently added into 100 parts of aqueous solution in which 0.5 part of sodium hexametaphosphate (meaning wt. parts the case with the following) and well dispersed while stirring, 50 parts of 10% cationic starch (CATO KOTE-485, manufactured by Oji National Co., Ltd.) and 12 parts (solid content) of styrene-butadiene latex (DOW 670, manufactured by Dow Chemical Co. Ltd.) are added into it, and added with 10 parts (solid content) of para-phenyl phenolic resin dispersion pH of liquid is adjusted to 9.0 with 20% caustic, soda so that it can be prepared as coating liquid. Coating liquid is coated on quality paper of 40 g/m² by means of air knife coater so that the coating amount may indicate 7 g/m² (solid content).

EXAMPLE 2:

[0010] After 50 parts of kaolin (Ultra-White-90) and 50 parts of calcium carbonate (PC) are gently added into 100 parts of aqueous solution in which 0.5 part of sodium hexametaphosphate is dissolved while stirring so that it may be well dispersed, it is added with 80 parts of 10% cationic starch (CATO KOTE -485) and 10 parts (so1id_`content) of styrene-butadiene latex (DOW-670) and then well dispersed and with 10 parts (solid content) of paraphenyl phenolic resin dispersion so that it may be well dispersed, pH is adjusted to 9.0 with 20% caustic soda so that coating liquid can be prepared. Coating liquid thus obtained is coated on quality paper of 40 g/m² by means of air knife coater in such a way that the coating amount may indicate 7 g/m² (solid content).

COMPARISON EXAMPLE 1:

[0011] By treating in the same way as indicated in Example 1 except that equivalent of cationic starch (CATO KOTE - 485) as described in Example 1 is substituted by that of starch oxide (MS-3800, manufactured by Nihon Food Co. Ltd.) it is prepared.

COMPARISON EXAMPLE 2:

[0012] By treating in the same way, as described in Example 2 except that equivalent of cationic starch (CATO KOTE - 485) as described in Example 2 is substituted by etherized starch (Unique Gum A# 1500, manufactured Matsutani Chemical Co. Ltd.) it is prepared.

COMPARISON EXAMPLE 3:

[0013] By treating in the same way as described in Example 3 except that equivalent of cationic starch (CATO KOTE- 485) is substituted by esterized starch phosphate (MS-4600, manufactured by Nihon Food Co. Ltd) it is prepared.

(TEST RESULT)

[0014] While laminating developer sheet obtained through the aforementioned Example and Comparison Example under the aforementioned coupling paper they are allowed to form color by applying pressure 96 kg/cm through calendering and the following values are measured.

(One hour after subjected to calendering). o Yellowing property of developed paper due to sunlight

[0015] After it is irradiation-treated with direct sunlight indoors for 7 hours, it is measured by means of color differential meter by Nihon Denshoku Co. Ltd. through blue filter. It indicates that the higher the values are, the less yellowing becomes.

o Yellowing property of developed paper due to nitrogen oxidant

[0016] After developed paper is set aside in vessel containing nitrogen oxidant of 150 ppm, the value is measured through blue filter by means of color differential meter. It indicates that the higher the value is, the less yellowing becomes.

[0017] It can be understood from the aforementioned Table that the effect for prevention of yellowing due to sunlight and nitrogen oxidant is remarkably observed while maintaining coupling density on developer sheet of the present invention which uses cationic starch for the present invention.

Claims

1. A developer sheet for carbonless reproduction paper having a phenolic resin developer comprising cationic starch as an anti-yellowing adhesive or binder.

2. A sheet according to claim 1, wherein the developer further comprises an activated clay.

3. A sheet according to claim 1 or 2, wherein more than 50 parts of cationic starch are used per 100 parts of phenolic resin, by weight.

4. A sheet according to claim 3, wherein 80-150 parts of the starch are used.

5. A sheet according to any preceding claim, wherein the phenolic resin is a para-phenyl phenolic resih.