Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
1999-11-26
2002-05-14
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C428S537500, C523S404000, C523S414000, C523S415000, C523S416000, C523S417000, C523S420000, C525S523000
Reexamination Certificate
active
06387506
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition for paper-coating, and a coating composition for paper comprising the resin composition, a pigment and an aqueous binder. More particularly, a resin composition for paper coating and a coating composition for paper are provided which do not cause generation of formaldehyde and can impart excellent printing suitability and printing effect on paper. The present invention also relates to a coated paper having a coat mainly composed of a pigment and an aqueous binder, not causing generation of formaldehyde, having excellent printing suitability and printing effect and exhibiting a good printing gloss. The term “paper” used in this specification has wide meaning, and includes a so-called paperboard in addition to a paper in narrow meaning.
Coated paper obtained by applying a coating composition mainly composed of a pigment and an aqueous binder and conducting necessary treatments such as drying, calendaring treatment and the like is widely used in commercial prints, journals, books and the like owing to its favorable features such as excellent printing effect, However, remaining efforts are still being conducted for improving quality of coated paper accompanying elevated requirement of quality, speed up of printing and the like. Particularly in offset printing, which occupies significant portion of printing, ink-receiving property under influence of wetting water, water resistance of wet pick and the like, improvement and advancement in printing gloss and blistering resistance in web press are required.
For accomplishing these subjects, there are conventionally known methods of adding, to a coating composition for paper, melamine-formaldehyde resins, urea-formaldehyde resins, polyamidepolyurea-formaldehyde resins as described in JP-B-44-11667 and JP-A-55-31837 (=U.S. Pat. No. 4,246,153), block glyoxal resins as described in JP-A-63-120197, or the like, as a water-resistance imparting agent or as an additive for a binder. However, any of these conventional water-resistance imparting agents and additives for a binder are not necessarily satisfactory in practice since important defects or insufficient effects in some characteristics are recognized although they give some effective merits.
For examples, so-called aminoplasto resins such as melamine-formaldehyde resins, urea-formaldehyde resins and the like cause some problems such as not only that generation of formaldehyde during work up or from coated paper is so much but also that effect for improving ink-receiving property and blistering resistance is poor, effect of manifesting water-resistance is not obtained easily when pH of a coated composition increases, and the like.
Polyamidepolyurea-formaldehyde resins impart improved effects, such as an improvement in ink-receiving property and water-resistance, to some extent. However, using polyamidepolyurea-formaldehyde resins, generation of formaldehyde cannot be prevented since formaldehyde is used in producing the resins.
On the other hand, block glyoxal resins, which are known as an additive for a binder containing no formaldehyde, have very little effect on improvement in quality of coated paper, such as ink-receiving property, blistering resistance and the like, though they can impart water-resistance against wetting water to a certain extent.
There is another problem that coated papers prepared by using a coating composition compounding a water-resistance imparting agent, such as aminoplasto resins and polyamidepolyurea-formaldehyde resins as mentioned above, on paper substrates tend to have deteriorated printing gloss comparing to coated papers prepared by using a coating composition consisting essentially of pigments and aqueous-binders. The deterioration of printing gloss lowers high-quality feeling of paper, since the high-quality feeling of paper comes from contrast between the non-printed portions and the printed portions and higher printing gloss in the non-printed portions gives the higher contrast.
Under these circumstances, the present inventors have previously proposed, in JP-A-10-77599, use of a cross-linked amine compound which is a reaction product of an aliphatic amine with a compound selected from aldehydes glycidyl compounds and isocyanate compounds, as a resin component in a coating composition for paper, for raising quality of coated paper. The present inventors have further proposed, in JP-A-11-140792, use of a cross-linked amine compound which is a reaction product of a hetrocyclic amine with a glycidyl compound, as a resin component in a coating composition for paper.
PROBLEMS TO BE SOLVED BY THE INVENTION
It has been found that, when such a cross-linked amine compound, which is a reaction product of an amine with a glycidyl compound and is described in JP-A-10-77599 and JP-A-11-140792, is used as a resin component, thickening of a coating composition, deterioration in flowing property and the like may occur depending on combination with other components, used amount of this cross-linked amine compound, and the like. The present inventors have further studied for solving such problems and for solving the problem of deterioration of printing gloss caused by a coating composition. As a result, the present invention has been completed.
An object of the present invention is to provide a resin composition for paper-coating which can produce high qualities of coated paper such as high ink-receiving property, excellent water-resistance and the like; and causes no generation of formaldehyde, responding to requirements on quality of coated paper.
Another object of the present invention is to provide a resin composition for paper-coating which hardly causes disadvantages such as thickening, deterioration in flowing property and the like, and, accordingly, is easily handled, when mixed with a pigment and an aqueous binder to form a coating composition for paper.
Further object of the present invention is to provide a coating composition for paper using the above resin composition.
Still further object of the present invention is to provide a coated paper causing no generation of formaldehyde, having good properties such as high ink-receiving property and excellent water-resistance, and exhibiting good printing gloss, which is produced by using the above coating composition for paper.
MEANS FOR SOLVING THE PROBLEMS
The present invention provides a resin composition for paper-coating which comprises
(A) a cross-linked amine compound which is a reaction product of (a) an aliphatic amine and (b) a glycidyl compound having at least two glycidyl groups in the molecule, or a reaction product of (a) an aliphatic amine, (b) a glycidyl compound having at least two glycidyl groups in the molecule and (c) a compound selected from &agr;,&bgr;-unsaturated carbonyl compounds, &agr;,&bgr;-unsaturated nitrile compounds and &agr;-halocarboxylic acid groups; and
(B) at least one selected from a group consisting of (B1) non-polymer nonvolatile substance and (B2) polyhydric alcohols.
The present invention also provides a coating composition for paper which comprises
(A) the above-described cross-linked amine compound,
(B) at least one selected from a group consisting of non-polymer nonvolatile substances and polyhydric alcohols, in addition to
(C) a pigment and
(D) an aqueous binder.
The present invention further provides a coated paper which comprises (1) a paper substrate and (2) a coat on the surface of the paper substrate comprising
(A) the above-described cross-linked amine compound,
(B) at least one selected from a group consisting of non-polymer nonvolatile substance and polyhydric alcohols,
(C) a pigment, and
(D) an aqueous binder.
PRACTICAL EMBODIMENTS OF THE INVENTION
The resin composition for paper-coating of the present invention comprises (A) a cross-linked amine compound which is obtained by reacting specific components, and (B) (B1) a non-polymer nonvolatile substance, and/or (B2) a polyhydric alcohol.
The cross-linked amine compound (A) is obtained by reacting (a) an aliphatic amine an
Hamaguchi Toshishige
Hasegawa Toshiyuki
Kawamura Akira
Shibata Yutaka
Tanikawa Akira
Aylward D.
Dawson Robert
Stevens Davis Miller & Mosher L.L.P.
Sumitomo Chemical Company Limited
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