JPH07242823A - Curable thermochromic silicone resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, capable of satisfying the shelf life with time, excellent in adhesion to a silicone resin, etc., rich in flexibility and stretchability and useful as a thermochromic packing, etc., by dispersing a thermochromic microcapsule pigment in a medium consisting essentially of a thermosetting type silicone resin. CONSTITUTION:This composition is obtained by dispersing (A) a thermochromic microcapsule pigment enclosing a homogeneous compatible substance consisting essentially of an electron donative coloring organic compound, an electron accepting compound and a color change temperature regulator capable of determining the temperature for causing the color reaction of former two in (B) a medium consisting essentially of a thermosetting type silicone resin. The thermochromic microcapsule pigment accounts for 5-50wt.% in the total amount. Furthermore, the component (B) is an addition reactional and two-component type silicone resin and the wall membrane of the component (A) is preferably formed of any resin of an amino-aldehyde resin, an epoxy-acid anhydride cured resin, a natural or a synthetic water-soluble polymeric compound, a polyester resin, a golyurethane resin, a polyurea resin and a phenol resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a curable thermochromic silicone resin composition. More specifically, it is cured by the addition of a curing agent to form a thermochromic coating film that is rich in flexibility, elasticity, and adhesion on the surface of elastic cloth or silicone rubber, or thermochromic casting. The present invention relates to a curable thermochromic silicone resin composition which is effective for forming members.

[0002]

2. Description of the Related Art Heretofore, some proposals have been disclosed for a color material such as a thermochromic printing ink or a paint in which a thermochromic microcapsule pigment is dispersed in a vehicle containing a binder (Japanese Patent Publication No. 52-52). 7764, Japanese Patent Publication No. 51-
35414, JP-A-62-138568, etc.). The conventional coloring material described above fulfills the intended function for the purpose of forming a thermochromic printing image or a coating film on the surface of a non-stretchable material.

[0003]

However, the adhesiveness to the silicone resin (including rubber) molded product, the flexibility of the coating film, and the lack of stretchability, the surface of the stretchable molded product, the knitted woven fabric, the woven fabric, etc. It was not possible to form a thermochromic film capable of satisfying all of the adhesiveness, flexibility and stretchability with respect to the cloth. The present invention eliminates the above-mentioned problems, and a thermochromic film having adhesion to silicone resin (including rubber), cloth, etc., flexibility and elasticity, and a thermochromic silicone rich in flexibility and elasticity. An object of the present invention is to provide a curable thermochromic silicone resin composition which is effective for giving a cast cured product having an appropriate shape such as rubber packing and electronic parts.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a homogeneous compatible solution containing an electron-donating color-forming organic compound, an electron-accepting compound, and a discoloration temperature controlling agent that determines the temperature at which the color reaction of both of them occurs. The thermochromic microcapsule pigment encapsulating is dispersed in a medium mainly composed of a thermosetting silicone resin, and the curable thermochromic silicone resin composition accounts for 5 to 50% by weight of the total amount. . Furthermore, the thermosetting silicone resin is an addition reaction type two-component silicone resin, and is characterized by a combination of thermochromic microcapsule pigments composed of a wall film made of a polymer compound that does not become a catalyst poison of the resin.

Examples of the silicone resin (including rubber) include a heat-vulcanizable silicone rubber, a liquid silicone rubber, a one-component or two-component condensation type silicone resin, and an addition reaction type two-component silicone resin. Sulfur and liquid silicone rubbers are suitable for molding, but are unsuitable for inks, and condensation reaction type silicone resins do not satisfy the stretching strength, and in the one-component type, pigment dispersion is performed in advance in the vehicle. If it is attempted, the reaction starts due to the influence of moisture in the air, and it is not suitable as an ink or coating composition that requires storage stability in a liquid state.

The heat-curable silicone resin according to the present invention may be any one as long as it can be cured by adding a curing agent immediately before use. Above all, an addition reaction type two-component silicone resin is preferable. A silicone resin composed of a liquid vinyl group-containing organosiloxane, an organohydrogenpolysiloxane, a platinum catalyst, etc., which is put into practical use as a two- or three-liquid type and mixed just before use.

The thermochromic microcapsule pigment of the present invention is required to be formed of a wall film made of a polymer compound which does not become a catalyst poison of the heat-curable silicone resin. In addition reaction type silicone resin etc., for example, sulfur, phosphorus, nitrogen compounds, organometallic salts, etc. become catalyst poisons,
The wall film affected by the catalyst poison, for example, epoxy-amine curing resin, acid chloride-amine polymer (for example,
Polyamide resin), isocyanate-amine curing resin and the like have a curing inhibition due to the influence of residual amino groups and do not form an effective cured product.

The wall film of the microcapsule pigment of the present invention is effectively made of melamine-formaldehyde resin, epoxy-acid anhydride cured resin, natural or synthetic water-soluble resin, polyester resin, polyurethane resin, polyurea resin, phenol resin and the like. is there. Further, as an additive, a system containing no organic metal salt such as an organotin polymer stabilizer is effective. The thermochromic microcapsule pigment is mixed in a dispersed state at a ratio of 5 to 50% by weight in the entire composition. If it is less than 5% by weight, it is difficult to clearly see the color change, and if it exceeds 50% by weight, there is residual color after erasing, and 10 to 30% by weight is preferable. Here, in order to adjust the viscosity and the like, a solvent or the like can be appropriately mixed to form a part of the medium.

The above-mentioned resin composition of the present invention is stable over time, and is mixed with a curing agent immediately before use to prepare a printing ink or paint by applying a conventionally known technique to print or paint on the surface of an object. Form a film. When a block-shaped or sheet-shaped molded product is obtained, the composition is applied, and a known means such as casting or compression pressing is applied.

The printing or coating film has a thickness of several μm to 400 μm.
The range of m (preferably ten and a few μm to 300 μm) is suitable in terms of color development effect, practicality and the like. In order to impart light resistance, an ultraviolet absorber is dispersed in the silicone resin main component on the surface of the printed or coated film, an appropriate cosolvent is added to form a topcoat base, and a curing agent is added immediately before use. To use.

The thermochromic material constituting the thermochromic microcapsule pigment is a conventionally known reversible thermochromic material of the type which develops and decolors at a predetermined temperature by an electron transfer reaction.
Japanese Patent Publication No. 51-44706, Japanese Patent Publication No. 51-44708
No. 52-7764, Japanese Patent No. 51-35414
No. 1, Japanese Patent Publication No. 1-29398, etc.
In addition, a quasi-reversible thermochromic material (that is, a temperature change) containing a color-memory thermosensitive dye which exhibits a large hysteresis characteristic and is described in Japanese Patent Publication No. 4-17154 previously proposed by the applicant. The shape of the curve plotting the coloring density by means of a path that differs greatly depending on whether the temperature rises from the low temperature side of the discoloration temperature range or the temperature decreases from the high temperature side of the discoloration temperature range. Discoloring type: It is also effective to store and retain the appearance of being changed at a temperature below the low temperature side discoloration point or above the high temperature side discoloration point in a room temperature range between the low temperature side discoloration point and the high temperature side discoloration point. The particle size of the thermochromic microcapsule pigment is 1 μm to 50
The range of μm (preferably about several μm to 20 μm) is effective in terms of dispersibility and coloring effect.

[0012]

[Function] The thermochromic microcapsule pigment is dispersed in a medium mainly composed of a heat-curable silicone resin, and is normally kept in an uncured state.
Gives a cured film or cast cured product. The thermochromic microcapsule pigment is a pigment formed by a wall film that does not become a catalyst poison of a heat-curable silicone resin, and gives a desired cured product without inhibiting the curing of the resin.

[0013]

【Example】

Example 1 Preparation of thermochromic microcapsule pigment A 6 parts of crystal violet lactone, 6 parts of bisphenol A, and 100 parts of cetyl alcohol were heated and dissolved to obtain an encapsulating composition consisting of a homogeneous compatible solution. 20% caustic soda aqueous solution was added to 200 parts of 3.0% aqueous solution of ethylene-maleic anhydride copolymer (trade name: EMA-31, manufactured by Monsanto Co.) to adjust pH to 4.0, and the above-mentioned inclusions Was emulsified and dispersed in this aqueous medium, and the system temperature was raised to 60 ° C. Separately, 10 parts of melamine was added to 30 parts of 37% aqueous formaldehyde solution and reacted at 60 ° C. for 15 minutes to prepare an aqueous prepolymer solution, which was added dropwise to the emulsion and heated to 70 ° C. with gentle stirring. The mixture was heated and encapsulated for 3 hours. The obtained capsule dispersion was dried by a spray drying method to obtain a thermochromic microcapsule pigment A.

A curable silicone resin composition was prepared by mixing 10 parts of the microcapsule pigment A with 100 parts of an addition reaction type two-component silicone rubber (product number: KE-1300T, manufactured by Shin-Etsu Silicone Co., Ltd.). Then a curing agent (product number: C
AT-1300, Shin-Etsu Silico) 10 parts, and print on a silicone rubber sheet with a silk screen plate,
Heated at 50 ° C. for 30 minutes. The cured film adhered to the rubber of the substrate and expanded and contracted in accordance with the expansion and contraction of the rubber, and exhibited the desired thermochromic property (blue-violet at 30 ° C or lower, colorless at 40 ° C or higher). Printing on a cotton knit for T-shirts in the same manner as above to form a thermochromic image, a thermochromic film having flexibility and excellent washing resistance was formed.

Example 2 The curable composition of Example 1 was poured into a packing mold and 10
After heating at 0 ° C. for 30 minutes, the mixture was left at room temperature for 1 day and taken out to obtain a thermochromic packing.

Example 3 In the inclusion of the thermochromic microcapsule pigment A of Example 1, undecyl myristate was used in place of cetyl alcohol, and other components were the same, and microcapsules were prepared in the same manner as in Example 1. Color-memory microcapsule pigment B
(Blue ← → colorless: low temperature side color change point 16 ° C, high temperature side color change point 3
4 ° C) was obtained. The silicone rubber sheet printed matter and the cotton knit for T-shirt obtained by using the same in the same manner as in Example 1 were colored blue at 10 ° C., kept the colored state at room temperature of 25 ° C., and at 36 ° C. The color was erased and the decolorized state was maintained at room temperature. The aspect could be retained and visualized in an alternating manner at room temperature.

[0017]

Since the curable thermochromic silicone resin composition of the present invention is a composition which is cured by adding a curing agent at the time of use, it is normally kept in an uncured dispersed state and stored with time. In addition to satisfying the properties and being convenient to use, it is excellent in adhesion to silicone resin or rubber, has flexibility and stretchability, and is suitable for thermal discoloration processing of the material. Furthermore, a thermochromic film having excellent flexibility and elasticity can be applied to textiles and the like.
Further, since a thermochromic cured product can be easily obtained by casting, it is effective for forming a heat management member such as thermochromic packing and thermochromic electronic parts.

Claims (3)

[Claims] 1. A thermochromic microparticle containing an electron-donating color-developing organic compound, an electron-accepting compound, and a homogeneous compatibilized solution containing a color-changing temperature controlling agent that determines the temperature at which the color reaction of both of them occurs as essential components. The capsule pigment is dispersed in a medium mainly composed of a heat-curable silicone resin, and the total amount is 5 to 50% by weight.
Curable thermochromic silicone resin composition comprising 2. The heat-curable silicone resin according to claim 1 is an addition reaction type two-component silicone resin. 3. The thermochromic microcapsule pigment according to claim 1, wherein the wall film is an amino-aldehyde resin, an epoxy-anhydride cured resin, a natural or synthetic water-soluble polymer compound, a polyester resin, a polyurethane resin, It is formed of a resin selected from polyurea resin and phenol resin.