JP2005008848A - Water discolorating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composition which can improve resistance to abrasion and bending of a porous layer containing a pigment of a low refractive index without being influenced by a preserving time until printing, and also gives the layer a moisture keeping character which ensures a speed of discoloration and a duration of wet state when written by water. <P>SOLUTION: This composition is not influenced by preserving the time until printing by using an acrylic resin and a wetting agent, or the like as components of a binder resin, can secure resistance to abrasion and bending by using a plasticizer and a surface active agent, can improve, without damaging concealability in a dried state and transparency in a wetted state, concealability of the porous layer by using an aluminium silicate as the pigment having the low refractive index and whiteness by joint use of a magnesium carbonate. Further, use of a wetting agent makes a time of keeping a state of a changed color longer and joint use of an acrylic-vinyl acetate copolymer improves water permeability of a painted film and can accelerate a speed of changing color by wetting. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water-changing composition. More specifically, the present invention relates to a water discoloring composition which absorbs a liquid such as water and changes to a state different from the normal state and returns to the normal state upon drying.

  Conventionally, a processed paper or sheet has been disclosed in which a porous layer containing a low-refractive index pigment is provided on a support, and the porous layer is made transparent by absorbing liquid to reveal the color tone of the lower layer. In JP-A-11-198271 (see Patent Document 1), it is shown that fine silica is used as the low refractive index pigment, and in JP-A-11-198272 (see Patent Document 2), It is shown that urethane resin is used as the binder resin.

JP-A-11-198271 JP-A-11-198272

  However, when a urethane resin is used as the binder resin, it is necessary to add a crosslinking agent for improving the adhesive strength of the resin. Crosslinking starts from the point of addition of the crosslinking agent, the binder resin is cured, and printing is performed. There was a problem that it could not take a long time before. Moreover, since the cross-linked urethane resin has a hard property, there is a drawback that when the printed material is folded, the coating film is easily folded along with the folding.

  The object of the present invention is to eliminate the cross-linking and hardening of the water-changing composition and not to be affected by the time until printing, and to improve the wear resistance and bending resistance of the porous layer containing a low refractive index pigment. It is. Moreover, it is to obtain the moisture retention property that ensures the discoloration speed and the wetness retention time in water writing.

  The present invention forms a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a colored support, and the porous layer is transparent or translucent in a liquid-absorbing state. It is a water discolorable composition for visualizing water, wherein the binder resin contains at least an acrylic resin. In addition, by including a plasticizer in the acrylic resin, the wear resistance and the bending resistance of the porous layer containing the low refractive index pigment are improved.

  Furthermore, by using aluminum silicate for the low refractive index pigment, the concealability of the porous layer is enhanced, and as the low refractive index pigment, magnesium carbonate is further added to improve the whiteness of the porous layer. In addition, the addition of a surfactant has the effect of making the porous layer hydrophilic and increasing the water absorbability.

  Further, it is assumed that the time until printing is not affected by including a wetting agent. In addition, by adding a moisturizer, surfactant, etc., the permeability and moisture retention of the porous layer are improved, the discoloration speed is increased, and the wetness retention time when writing with a water brush on the coating film is prolonged. Has an effect. In addition, even when an acrylic resin and an acrylic-vinyl acetate copolymer resin are used in combination as a binder resin, the water permeability of the coating film is improved, so that the water wettability when writing with a water brush is improved, and the discoloration speed is improved. Get faster.

  In the present invention, the porous layer in which the low refractive index pigment is fixed to the binder resin in a dispersed state has a concealing property in a normal state, that is, in a dry state, exhibits a white color, and absorbs a liquid such as water. It becomes transparent or semi-transparent to reveal the color tone of the lower layer.

  In the present invention, an acrylic resin is used as the binder resin, or at least an acrylic resin is contained. By containing an acrylic resin in the binder resin, the binder resin is not cured. Moreover, it is not necessary to prevent yellowing as in the case of using a urethane-based resin for the porous layer and to improve the bendability of the coating film. As said acrylic resin, 0.5-2 weight part can be used with respect to 1 weight part of low refractive index pigments, Preferably 0.8-1.8 weight part can be used. When the amount exceeds 2 parts by weight, the water permeability is deteriorated and the concealability of the porous layer is deteriorated. On the other hand, when the amount is less than 0.5 parts by weight, the strength of the porous layer is decreased.

  The binder resin may be used in combination with an acrylic-vinyl acetate copolymer resin in addition to the acrylic resin. By using the acrylic-vinyl acetate copolymer resin in combination, the coating film has no yellowing and the water permeability of the coating film is improved, so that the water wettability is improved and the discoloration speed is increased. The acrylic resin and acrylic-vinyl acetate copolymer resin can be added as an emulsion.

  In addition, a plasticizer can be added to the binder resin in order to give flexibility to the resin. The plasticizer can be used as long as it is a known one, but considering the influence of environmental hormones on the human body, those that are not environmental hormones are preferred, and edible plasticizers are preferred. Specific examples include glycerin diacetomonolaurate.

  As the binder resin other than the acrylic resin and acrylic-vinyl acetate copolymer resin, nylon resin, vinyl acetate resin, acrylic polyol resin, vinyl chloride-vinyl acetate copolymer resin, maleic acid resin, polyester resin, styrene resin, Styrene copolymer resin, polyethylene resin, polycarbonate resin, epoxy resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, methyl methacrylate-butadiene copolymer resin, butadiene resin, chloroprene resin, melamine resin, and the above resins Examples include emulsion, casein, starch, cellulose derivative, polyvinyl alcohol, urea resin, phenol resin, and epoxy resin. The binder resin is appropriately selected depending on the properties of the support. For example, when the support is a fabric, a nylon resin or the like is preferably used in addition to the acrylic resin.

  Examples of the low refractive index pigment include fine particle silicic acid, barite powder, precipitated barium sulfate, precipitated calcium carbonate, gypsum, clay, talc, alumina white, basic magnesium carbonate, and the like. It is in the range of 4 to 1.7, and exhibits good transparency when water or the like is absorbed. The particle size of the low refractive index pigment is not particularly limited, but 0.03 to 15.0 μm is preferably used. Two or more of the low refractive index pigments can be used in combination. In addition, as a low-refractive-index pigment used suitably, an aluminum silicate is mentioned by the point which improves hiding property.

  Moreover, when using an aluminum silicate as a low refractive index pigment, basic magnesium carbonate can be used together and there exists an effect which the whiteness of a porous layer improves in addition to provision of the concealment property of an aluminum silicate.

The low refractive index pigment depends on properties such as type, particle diameter, specific surface area, oil absorption, etc. In order to satisfy both the concealing property in the normal state and the transparency in the liquid absorption state, the coating amount is 1 g. is preferably / m ² ~30g / m ^2, more preferably ^{5g / m 2 ~20g / m 2} . If it is less than 1 g / m ² , it is difficult to obtain sufficient concealability in a normal state, and if it exceeds 30 g / m ² , it is difficult to obtain sufficient transparency upon liquid absorption. The low refractive index pigment is dispersed in a vehicle containing a binder resin as a binder, and is applied to an object, and then the volatile matter is dried to form a porous layer.

  The water-discoloring composition of the present invention may be added to a conventionally known metallic pigment such as titanium dioxide-coated mica, iron oxide-titanium dioxide-coated mica, iron oxide-coated mica, guanine, or sericite, or a general dye or pigment. Fluorescent dyes and pigments can be added to diversify the color change. Furthermore, you may use together the reversible thermochromic material which changes a color reversibly with a temperature change. A reversible thermochromic layer containing a reversible thermochromic material can also be provided.

  A surfactant can be added to accelerate the absorption of water into the porous layer. This is because the porous layer becomes hydrophilic due to the surfactant, and when applied with a brush containing water, the familiarity with water is improved and the water absorption rate is increased. Surfactants include anionic surfactants such as carboxylic acid type, sulfate ester type, sulfone type, and phosphate ester type, quaternary ammonium salt type, amine salt type, cationic cations such as polymer cation, betaine type, and amino acid type. , Amphoteric activators such as multi-functional group-containing polymers, nonionic activators such as ether type, ester type, amino ether type and alkylamide type, other fluorine based activator, silicone based activator, reactive activator it can. Specific examples are listed below, but disodium (POE) alkylsulfosuccinate, which is an anionic activator, is preferable from the viewpoint of the permeability of the coating film.

  As an anionic activator, N-acyl amino acid, acyl sarcosine, acyl alanine, alkyl ether carboxylic acid, polycarboxylic acid hydrolyzed collagen, sulfate ester type alkyl sulfate ester, higher alcohol sulfate ester, which is a carboxylic acid type fatty acid soap, Sulfated oil, funnel oil, POE alkyl ether sulfuric acid, POE alkyl phenyl ether sulfuric acid, fatty acid mono (di) glycerin ester sulfuric acid, protein sulfate ester, sulfonic acid type alkyl sulfonic acid, alkyl benzene sulfonic acid, (methyl) taurine, ( Di) alkylsulfosuccinic acid, (POE) disodium alkylsulfosuccinic acid, alkylsulfoacetic acid, POE alkylphenyl ether (ethyl) sulfonic acid, (POE) alkyl as phosphate ester Examples include ruphosphoric acid esters and (POE) alkylphenyl phosphoric acid esters.

  Cationic activators include quaternary ammonium salt methyl type, tri, di, monomethyl, EO addition type, benzyl type, tetraalkyl type, and alkylpyridine (quinoline) type. Amine salts include alkylamine, alkyldiamine, high Examples of the molecular cation include cationized cellulose and a cation group-containing polymer. Examples of the amphoteric active agent include alkylbetaines, amidebetaines, sarcosine, alanine, alkylamidopropylhydroxysulfobetaines, imidazolines, and alkyldiaminoglycines.

  Nonionic active agents include ether type POE-POP copolymer (block copolymer, random copolymer), POE-POP alkyl ether (POE alkyl ether, POE alkyl allyl ether, POE polycyclic phenyl ether, acetylene glycol derivative), ester type POE fatty acid ester (polyhydric alcohol fatty acid ester, sorbitan ester, POE-added sorbitan ester, POE-added sorbit ester, glycerin mono-fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester), monoether type and diamine type POE as amino ether type Examples include alkylamine and alkylamide types.

  In the present invention, wetting agents such as ethylene glycol and propylene glycol can be used in order to prevent the printability from being impaired by drying the water-changing composition during printing of the coating film.

  In addition, since the above-mentioned wetting agent is scattered by heat drying of the coating film, it does not remain in the coating film. Therefore, in order to provide moisture retention of the coating film, a solid humectant such as urea, polyacrylic acid soda crosslinked body, etc. Can be used.

  In addition to the above, water, preservatives, antifoaming agents, and thickeners can be used as appropriate.

  Examples of the support include paper, synthetic paper, synthetic leather, leather, plastic, glass, ceramics, wood, stone, and the like in addition to fabrics such as woven fabrics, knitted fabrics, braided fabrics, and nonwoven fabrics. When the fabric is used as a support, a woven fabric having excellent smoothness on the surface of the fabric is preferably used from the viewpoint of film formation of the porous layer. When the smoothness of the fabric surface is poor, or when the permeability of the ink inside the fabric is large and the film formation of the porous layer is poor, the fabric is subjected to a treatment such as water repellency, The film forming property of the porous layer can be improved.

  As a method of forming the porous layer, conventionally known coating methods, for example, printing means such as screen printing, offset printing, gravure printing, coater, tampo printing, transfer, brush coating, spray coating, electrostatic coating, Means such as electrodeposition coating, flow coating, roller coating, and immersion coating may be mentioned.

  Next, the structure in the case of using the water color-changing composition of the present invention and the change in the dry state (non-liquid absorption state) and the state in which water or the like is absorbed will be described. The water discolorable composition of the present invention forms a porous layer containing a low refractive index pigment and a binder resin laminated on a colored support, has a concealing property when dried, and has a lower layer. The colored support is concealed and made transparent or translucent in a state where water or the like is absorbed to reveal the lower layer. Therefore, even if the support is a single color, the wet layer becomes transparent or semi-transparent by partially wetting the porous layer using a brush, brush, pen, stamp, etc., and the color tone of the lower layer is visually recognized. A desired image can be displayed. When the water in the porous layer evaporates and dries, the porous layer again conceals the lower layer and returns to its original state. Therefore, it is possible to provide a pattern or multicolor pattern on the support and conceal it with a porous layer, as well as a pattern that is associated with or integrated with a pattern that is visually recognized when the porous layer is made transparent by liquid absorption. It is also possible to visually recognize an image in which the symbols are combined in the liquid absorption state by being provided on the layer. It is also possible to form a pattern with a porous layer colored by adding a general pigment, etc., so that the porous layer absorbs liquid and cannot be visually discriminated by the color tone of the support seen through. In addition, the color tone of the porous layer can be set. Furthermore, as a support having transparency, for example, a porous three-dimensional object can be provided with a porous layer, and the three-dimensional object itself can be seen through when the porous layer becomes transparent by liquid absorption.

  The present invention uses an acrylic resin, wetting agent, etc. as a binder resin, and can be used without being affected by the time until printing, and by using a plasticizer and a surfactant together, it ensures abrasion resistance and bending resistance. In addition, by using aluminum silicate as a low refractive index pigment, the concealability of the porous layer, or the whiteness can be increased by using magnesium carbonate together, in the concealability in the dry state and the liquid absorption state Thus, it is possible to provide a water discoloring composition having excellent practicality in various fields such as the toy field, the decoration field, and the design field without impairing the transparency of the film. In addition, the use of a moisturizer can increase the discoloration maintenance time, and the combined use of acrylic-vinyl acetate copolymer resin can increase the discoloration speed due to water wetting in order to improve the water permeability of the coating film. it can.

Next, the present invention will be described in detail with reference to examples.
In Examples 1 to 3 and Comparative Examples 1 to 4, an acrylic resin emulsion (acrylic-vinyl acetate copolymer resin emulsion if necessary), plastic is used in a solution in which water, an activator, a lubricant, a humectant, or the like is dissolved or dispersed. Add the agent and mix with a dissolver. Thereafter, an extender pigment such as a low refractive index pigment was stirred and mixed with a dissolver, and dispersed with a disperser such as a three-roll mill to prepare a water discoloring composition. Further, a colored ink was applied to the support of the fabric, and then the water discoloring composition was applied by screen printing as a concealing layer to form a film. The composition and evaluation of the water discoloring composition at that time are shown in Table 1. The composition shown in Table 1 is% by weight.

In the table, each raw material composition is as follows.
1) Low refractive index pigment Sipernat 820; aluminum silicate CI No. 77004 (manufactured by Tegusa)
Tansan magnesium; Magnesium carbonate CI No. 77713 (manufactured by Kamishima Chemical Co., Ltd.)
2) Binder resin Mobile DM772; Acrylic emulsion 46% resin content (manufactured by Clariant Polymer Co., Ltd.)
Mobile DM5; acrylic / vinyl acetate copolymer emulsion, 53% resin content (manufactured by Clariant Polymer Co., Ltd.)
3) Plasticizer Riquemar PL-012; Glycerin diacetomonolaurate (manufactured by Riken Vitamin Co., Ltd.)
4) Surfactant Nonion ST-221; Polyoxyethylene sorbitan monostearate (HLB = 14.9) (manufactured by NOF Corporation)
Sanmorin OT-70; Dioctyl sulfosuccinate sodium (manufactured by Sanyo Chemical)
5) Moisturizer Urea

(Evaluation)
1) Color difference between the coated surface at the time of drying / water absorption The color difference ΔE ^* between the dried coated surface of the test sample and the coated surface at the time of water absorption was measured with a color difference meter CR-300 manufactured by Minolta.
2) Abrasion resistance When the surface of the test sample is written 500 times under conditions of 50 g of load, pen angle of 65 degrees, and writing speed of 7 cm / min. evaluated.
Evaluation
○: No change △: Slight wear ×: Continuous wear
3) Cellophane tape peeling Apply cellophane tape to the test sample and rub it with an eraser to completely adhere the tape to the coating film. The tape was peeled off instantaneously with one end of the tape, and the degree of peeling was visually evaluated.
Evaluation
○: No change △: Slight peeling ×: Continuous peeling
4) Discoloration speed The time for discoloration when writing on the concealment layer with a pen containing water was measured.
○: Within 1 second △: 1-3 seconds ×: 3 seconds or more
5) Moisturizing property After writing on the concealment layer with a pen containing water, the time for drying and returning the discoloration trace was measured.
○: 2 minutes or more △: 1-2 minutes ×: 1 minute or less
6) Bending resistance The specimen is folded 180 degrees and then 180 degrees in the opposite direction. This operation was repeated 5 times, and the peeling state of the film was confirmed visually.
○: No peeling ×: Peeling From the above results, the water-discoloring compositions of the examples did not harden over time, and could ensure the color difference of the coated surface at the time of drying / water absorption, as well as abrasion resistance and hiding properties. The peel strength, bending resistance, discoloration speed and moisture retention were also good.

Claims (8)

On the colored support, a porous layer in which a low refractive index pigment is fixed in a dispersed state in a binder resin is formed, and the porous layer is transparent or semi-transparent in a liquid-absorbing state so that the changed appearance can be visually observed. A water discoloration composition, wherein the binder resin contains at least an acrylic resin. The water discolorable composition according to claim 1, wherein the acrylic resin contains a plasticizer. The water discoloring composition according to claim 1 or 2, wherein the low refractive index pigment is aluminum silicate. The water discoloring composition according to claim 3, further comprising magnesium carbonate as a low refractive index pigment. The water discoloring composition according to claim 1, further comprising a surfactant. The water discoloring composition according to any one of claims 1 to 5, further comprising a wetting agent. The water discoloring composition according to claim 1, further comprising a humectant. The water color-changing composition according to any one of claims 1 to 7, wherein an acrylic resin and an acrylic-vinyl acetate copolymer resin are used in combination as the binder resin.