KR20200120697A - Color developing film with uneven structure, pressure test film, and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a color developing film and a pressure test film and a method of manufacturing the same. The color developing film may include a substrate configured to form a color developing film by applying another layer thereon; An uneven structure layer formed on the substrate; And a microcapsule coated on the uneven structure layer and containing an electron-donating colorless dye precursor therein, wherein the electron-donating colorless dye precursor is in contact with an electron-accepting compound to form a color Layer; When the chromogenic film is under pressure, the concave-convex structure layer compresses the chromogenic layer so that the microcapsules in the chromogenic layer are broken and the electron-donating colorless dye precursor is released. By using the uneven structure layer, the color developing film can achieve reduction and concentration of the internal pressure region of the pressure test film and the actual internal pressure region of the microcapsule, so that even when a small pressure is applied to the pressure test film, the high sensitivity of the pressure test film is Can be achieved.

Description

Color developing film with uneven structure, pressure test film, and manufacturing method thereof

The present invention relates to a color developing film, a pressure test film, and a method of manufacturing the same, and more specifically, to a color developing film having an uneven structure, a pressure test film, and a method of manufacturing the same.

The pressure test is mainly applied in various production and processing procedures with stringent requirements for pressure, such as lamination of printed circuit boards, confirmation and adjustment of pressure between rollers, lamination of liquid crystal glass panels, assembly of engine cylinders, and the like. Generally, a pressure test instrument is adopted for the pressure test. However, since these pressure test methods are complex in operation, have hysteresis in the measurement results, and test precision and sensitivity are low, they are suitable only for pressure tests in a narrow area, and pressure tests in specially shaped areas or online pressure monitoring. Not suitable for

To facilitate the application of this pressure test, many pressure test films have been used. The pressure test film typically comprises a chromogenic portion and a color-developing portion, the chromogenic portion comprising a microcapsule containing an electron-donating colorless dye precursor. Microcapsules break when the chromogenic part is under pressure to release an electron-donating colorless dye, and the electron-donating colorless dye comes into contact with the electron-accepting compound to color the chromogenic part, and then the magnitude and point of the pressure are present. It is determined according to the colored area and chromaticity of the colored part.

However, the existing pressure test film cannot realize the reduction and concentration of the press-bearing region of the pressure test film and the actual internal pressure region of the microcapsule. In practical use, significant pressure is required for the dye to contact the electron-accepting compound to form a color after breaking the microcapsules to release an electron-donating colorless dye. Therefore, when using a pressure test film to test a small pressure, it is difficult to perform a pressure test with high sensitivity.

Therefore, there is a need for a pressure test film capable of testing pressure in a small-pressure test environment.

To this end, the present invention reduces and concentrates the internal pressure region of the pressure test film and the actual internal pressure region of the microcapsules by adding a concave-convex layer between the substrate and the color developing layer of the pressure test film. Achieves high sensitivity.

Specifically, according to one embodiment of the present invention, a substrate configured to form a color developing film by applying another layer thereon; An uneven structure layer formed on the substrate; And a microcapsule coated on the uneven structure layer and containing an electron-donating colorless dye precursor therein, wherein the electron-donating colorless dye precursor is in contact with an electron-accepting compound to form a color A chromogenic film comprising a layer; is provided, and when the chromogenic film is under pressure, the uneven structure layer compresses the chromogenic layer so that the microcapsules in the chromogenic layer are broken and electron-donating colorless dye precursors are released.

Preferably, the color developing film further includes an undercoat layer disposed between the substrate and the uneven structure layer and configured to stably support the uneven structure layer on the substrate.

Preferably, the uneven structure layer has at least two convex portions, and the linear distance L between the uppermost portions of two adjacent convex portions satisfies the following relationship: D50×0.2≦L≦D50×0.8, wherein D50 represents the particle diameter corresponding to the cumulative particle size distribution of 50% of the microcapsules.

Preferably, the uneven structure layer is formed by UV resin.

Preferably, the convex portion on the uneven structure layer is in the form of a cylinder, a cone, a rectangular parallelepiped, or a cube.

Preferably, the convex portion on the uneven structure layer has a pointed top.

With regard to the method of forming the uneven structure layer, reference may be made to an application titled "Uneven structure manufacturing apparatus" filed by the present applicant on the same date as the present application.

Preferably, the undercoat layer is formed by coating a water-based resin, and the water-based resin is preferably polyvinyl alcohol or styrene-butadiene rubber.

According to another embodiment of the present invention, a color developing film layer containing the color developing film as described above; And a chromogenic film layer containing a chromogenic material of an electron-accepting compound is provided.

According to another embodiment of the present invention, there is provided a method for producing a color developing film comprising the following steps:

Adding a reactive diluent to the UV resin and stirring well, adding a photoinitiator or an auxiliary agent and stirring well, thereby preparing a slurry having an uneven structure;

An oil phase and an aqueous phase containing electron-donating colorless dye precursors were prepared, and the oil phase was added to the aqueous phase by adopting a film emulsification method to form an emulsion, and then a curing agent was added and stirred well, Heating to 50° C. and reacting for 4 hours to form a microcapsule dispersion, and finally adding a binder and water and stirring well to prepare a color developing layer slurry; And

Step of sequentially applying the uneven structure layer slurry and the color developing layer slurry on a substrate to form a color developing film applicable to a pressure test film.

According to another embodiment of the present invention, there is provided a method of producing a pressure test film comprising the following steps:

Adding a reactive diluent to the UV resin and stirring well, adding a photoinitiator or an auxiliary agent and stirring well, thereby preparing a slurry having an uneven structure;

An oil phase and an aqueous phase containing electron-donating colorless dye precursors were prepared, and the oil phase was added to the water phase by adopting a film emulsification method to form an emulsion, and then a curing agent was added and well stirred, heated to 50° C., and for 4 hours Reacting to form a microcapsule dispersion, and finally adding a binder and water and stirring well to prepare a color developing layer slurry;

Adding activated clay to water and stirring to pre-disperse, followed by sand milling with a sand mill to form an activated clay aqueous dispersion, and finally adding a binder and stirring well to prepare a chromogenic layer slurry;

Sequentially applying the uneven structure layer slurry and the color developing layer slurry on the substrate to form a color developing film applicable to the pressure test film;

Applying the color developer layer slurry on a substrate to form a color developer film applicable to a pressure test film; And

Combining the chromogenic film and the chromogenic film to form a pressure test film.

When applying the pressure test film of the present invention, the chromogenic film material (L) and the chromogenic film material (K) are superimposed in such a way that the two films face each other, and are disposed between the pressure-bearing surfaces. , When a pressure greater than the breakage threshold of the microcapsules is applied, the microcapsules are broken and the electron-donating colorless dye is released. Initiate the reaction. Thereafter, the pressure test can be achieved by observing and measuring the depth of the color of the colored area. Since the color-forming principle of electron-donating colorless dyes and electron-accepting compounds is used in the pressure test, it has high sensitivity and high resolution properties, and can particularly meet the requirements for use in a low temperature environment of 5°C to 15°C.

In addition, since the pressure test film of the present invention provides an uneven structure layer between the color developing layer and the undercoat layer, reduction and concentration of the internal pressure region of the pressure test film and the actual internal pressure region of the microcapsules can be achieved. According to the pressure conversion equation P = F/S, under the same pressure, when the inner pressure region decreases, the actual pressure applied to the microcapsules increases, and when the actual pressure is greater than the threshold, the microcapsules are broken and the electron-donating colorless dye After releasing, the dye comes into contact with the electron-accepting compound to form a color. Therefore, even if a small pressure is applied to the pressure test film, a high sensitivity of the pressure test film can be achieved.

For a better understanding of the invention and a clearer description of the implementation of the invention, the invention will now be described by way of example, with reference to the accompanying drawings:
1 is a schematic structural diagram of a color developing film material L according to an embodiment of the present invention;
2 is a schematic structural diagram of a pressure test film according to an embodiment of the present invention;
3 is a flow chart of a method of manufacturing a color developing film according to an embodiment of the present invention; And
4 is a flow chart of a method of manufacturing a pressure test film according to an embodiment of the present invention.

Specific embodiments of the present invention are described in detail below. It should be noted that the following description is only illustrative of some preferred embodiments of the present invention and should not be regarded as limiting the scope of the present invention. Other embodiments, features, embodiments, embodiments, and advantages of the present invention will become apparent to those skilled in the art from the following description. In addition, it is understood that any one or more of the concepts, expressions, embodiments, examples, etc. described in the present invention may be combined with any one or more of the other concepts, expressions, embodiments, examples, etc. described in the present invention. You have to understand. Accordingly, the teachings, descriptions, embodiments, examples, etc. set forth below should not be considered independent of each other.

In addition, examples of the drawings are not necessarily drawn to scale, and in some cases, features of the present invention may be exaggerated or minimized in the drawings to facilitate understanding of the present invention. In the drawings, like reference numbers generally refer to similar features.

1 is a schematic structural diagram of a color developing film according to an embodiment of the present invention. As shown in Figure 1, the color development film provided by the present invention is a color development film material composed of a color development film substrate 213, an undercoat layer 215, an uneven structure layer 217, and a color development layer 219 ( L), wherein the undercoat layer 215, the uneven structure layer 217, and the color developing layer are sequentially applied and attached to the color developing film substrate 213. The structure and function of the undercoat layer 215, the uneven structure layer 217, and the color developing layer 219 will be described in more detail below.

2 is a schematic structural diagram of a pressure test film according to an embodiment of the present invention. As shown in Fig. 2, the pressure test film provided by the present invention is composed of a chromogenic film layer containing a chromogenic film material (L) and a chromogenic film layer containing a chromogenic film material (K). The structure of the color developing film material L is as described above, and the color developing film material K is composed of a color developing film substrate 223 and a color developing layer 225. The pressure test film is formed by overlapping the color developing layer 219 of the color developing film and the color developing layer 225 of the color developing film in a manner in which the color developing layer 219 and the color developing layer 225 face each other. Note that the color developing film material (L) and the color developing film material (K) may not form a pressure test film during manufacture, but may be manufactured and sold as separate films, that is, a color developing film and a color developing film, respectively. Should be. However, during use, the color developing film and the color developing film have a structure such as a pressure test film by overlapping in a manner in which the color developing layer 219 of the color developing film and the color developing layer 225 of the color developing film face each other. For convenience, it is also referred to as a pressure test film).

Further, while using the pressure test film, by applying a pressure (P) between the pressure-resistant surface 211 of the color developing film and the pressure-resistant surface 221 of the color developing film, the microcapsules in the color developing film are under pressure. It is damaged to release an electron-donating colorless dye, and a color is formed when the electron-donating colorless dye meets the electron-accepting compound in the chromogenic layer, and the pressure (P) is determined according to the degree of the color formed thereafter. A pressure test film is used to achieve the pressure test purpose.

<Substrate>

The substrate described herein includes a substrate 213 of a color developing film and a substrate 223 of a color developing film. In an embodiment of the present invention, the substrate suitable for the present invention may adopt plastic film, paper, synthetic paper and other substrates. Specific examples of the plastic film include polyethylene terephthalate (PET), polythene (PE), polypropylene (PP), polyvinyl chloride (PVC), and the like. Specific examples of paper include high-quality paper, coated paper, art paper, and the like. Specific examples of synthetic paper include: synthetic paper formed of synthetic fibers such as polyethylene, polyamide, polyethylene terephthalate, or the like, or synthetic paper produced by laminating them on one or both sides of the paper. PET of 50 μm to 125 μm is preferred in the present invention.

<Undercoat Floor 215>

In the embodiment according to the present invention, the undercoat layer 215 functions to improve the adhesion of the uneven structure layer 217 on the color developing film substrate 213. The undercoat layer 215 is typically one or more water based synthetic or natural macromolecular materials such as styrene-butadiene rubber (SBR), acrylate latex, polyvinyl alcohol (PVA), gelatin, carboxymethylcellulose (CMC), and the like. It is composed of resin. PVA and SBR are preferred in the present invention.

<Uneven structure layer 217>

In the embodiment according to the present invention, the uneven structure layer 217 functions to apply a pressure applied to the surface of the pressure test film to the microcapsules in the color developing layer 219 after area conversion. The uneven structure layer 217 is composed of a UV resin, a reactive diluent and a photoinitiator.

In the embodiment according to the present invention, the UV resin in the uneven structure layer 217 is composed of two or more of the following UV resins, and the UV resin suitable for the present invention is, without limitation, urethane acrylate, epoxy acrylate, aliphatic And urethane acrylate. The reactive diluent in the uneven structure layer 217 includes, but is not limited to, a bifunctional monomer such as tripropylene glycol diacrylate (TPGDA) and dipropylene glycol diacrylate (DPGDA); Trifunctional monomers such as pentaerythritol triacrylate (PET3A) and trimethylolpropane triacrylate (TMPTA); It is composed of two or more reactive diluents containing multifunctional monomers such as dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PET4A), and the like. Photoinitiators include, but are not limited to, 1-hydroxycyclohexyl phenyl ketone (184), 2,4,6-trimethyl benzoyl-diphenyl phosphine oxide (TPO), 2-methyl-1-[4'-methylthiophenyl] -2-morpholino-1-propanone (907), and the like.

In an embodiment according to the present invention, the concave-convex structure layer 217 is disposed on the undercoat layer 215, and the concave-convex portion of the concave-convex structure layer 217 has at least two convex portions, and between two adjacent convex portions The linear distance L of satisfies D50×0.2≦L≦D50×0.8. When L<D50×0.2, the distance between adjacent convex portions is so small that the inner force region of the microcapsule cannot be effectively concentrated, and thus pressure distribution measurement cannot be achieved under low pressure conditions. In the case of L>D50×0.8, most of the microcapsules sink into the gaps between adjacent convex portions and are broken when pressed and cannot form color, and thus pressure distribution measurement cannot be achieved.

In the embodiment according to the present invention, the convex portion of the uneven structure layer 217 has a shape including, but not limited to, a cylindrical shape, a conical shape, a rectangular parallelepiped shape, a cube shape, and the like.

In the embodiment according to the present invention, the convex portion of the uneven structure layer 217 has a pointed top.

<Color development layer 219>

In an embodiment according to the present invention, the chromogenic layer 219 comprises microcapsules, a binder and an adjuvant, and the microcapsules contain an electron-donating colorless dye precursor. In an embodiment according to the invention, the microcapsules of the invention comprise at least two parts of an electron-donating colorless dye precursor solution and a microcapsule wall.

(Electron-donating colorless dye precursor solution)

In an embodiment according to the invention, the electron-donating colorless dye precursor solution contains at least one electron-donating colorless dye precursor and at least one solvent. The electron-donating colorless dye precursor acts as the main color former. As the electron-donating colorless dye precursor, known electron-donating colorless dye precursors such as fluoran compounds, indolyl peptide ketone compounds, rhodamine lactam compounds, spiropyran compounds, and phenothiazine compounds can be adopted. Electron-donating colorless dye precursors suitable for use in the present invention include, but are not limited to, crystal violet lactone (CVL), leucomethylene blue (BLMB), and the like.

The solvent mainly serves to dissolve the electron-donating colorless dye precursor, and known solvents such as diarylalkane such as 1-phenyl-1-dimethylphenylethane, diarylalkene, alkyl naphthalene such as diisopropyl naphthalene, iso Aliphatic hydrocarbons such as alkanes, natural animal and vegetable oils such as corn oil, castor oil, and rapeseed oil, and mineral oils can be used.

In an embodiment according to the invention, the electron-donating colorless dye precursor solution contains 3 to 12 parts of the electron-donating colorless dye precursor per 100 parts of the dye solution. When the electron-donating colorless dye precursor is less than 3 parts, the color density is insufficient, and when the electron-donating colorless dye precursor is more than 12 parts, the electron-donating colorless dye precursor 15 will crystallize and precipitate under a low temperature environment, As a result, effective color development components are reduced.

In addition, in the embodiment according to the invention, if necessary, a solvent having a relatively low boiling point may be added as a co-solvent in order to better dissolve the electron-donating colorless dye precursor in the solvent. Solvents with low boiling points suitable for use in the present invention include, but are not limited to, ketones such as acetone, methyl ethyl ketone, and the like, and esters such as methyl acetate, ethyl acetate, and the like.

(Microcapsule wall material)

In an embodiment according to the invention, the wall material of the microcapsules can be selected from known materials that are insoluble in both water and oil, such as polyurethaneurea, gelatin, melamine formaldehyde resin, etc., in the present invention, polyurethaneurea is desirable.

The wall material of the microcapsules can be formed by a known method such as an interfacial polymerization method, an in-situ polymerization method, a condensation method, and the like. In an embodiment according to the invention, the wall material is preferably formed using an interfacial polymerization method.

In an embodiment according to the invention, the wall material consists of at least a reactive monomer and a curing agent. Reactive monomers suitable for the wall material of the microcapsules include, but are not limited to, dicyclohexylmethane-4,4'-diisocyanate (HDI), hexamethylene diisocyanate (HMDI), polyisocyanate oligomers such as trimethylolpropane of hexamethylene diisocyanate. Adducts and trimethylolpropane adducts of xylylene diisocyanate. Curing agents suitable for the preparation of wall materials of microcapsules are, but are not limited to, polyhydroxy compounds such as aliphatic or aromatic polyols, polyamines such as triethylene tetramine and hexamethylene diamine, alkylene oxide adducts of aliphatic polyamines such as butylene of ethylene diamine. Any polyamine including oxide adducts and the like, and the molecule containing _two or more -NH groups or -NH ₂ groups may be used. In an embodiment according to the invention, preferably, the curing agent is used after being dissolved in water.

In an embodiment according to the invention, the particle size distribution of the microcapsules is characterized by a particle size distribution D50 of 5 μm to 15 μm, and a span of particle size distribution (D90-D10)/D50 of 0.5 to 1.2. If the D50 is less than 5 μm, the intra-pressure threshold of the microcapsules increases considerably, the practical application range is limited, and most of the microcapsules sink into the gaps between the convex structures due to the small particle size and participate in color generation. Can't. When the D50 exceeds 15 μm, the coating appearance of the pressure test film becomes uneven. When the span is less than 0.5, the manufacturing cost of microcapsules increases considerably. When the span is more than 1.2, since it is evident that large and small particles in the microcapsules are agglomerated due to different surface energy, the concentration and depth of the produced color are not uniform due to aggregation during the use of the pressure test film. , Thus the measurement precision is reduced.

(Binder and supplement)

In the embodiment according to the present invention, the binder in the color developing layer may adopt a water-soluble polymer such as starch, CMC, PVA, and the like.

In an embodiment according to the invention, the adjuvant comprises, but is not limited to, at least an emulsifier comprising an amphiphilic polymer such as PVA, CMC, starch, gelatin, and the like, with PVA being preferred in the present invention.

<Development layer 225>

In an embodiment of the present invention, the developer layer 225 includes an electron-accepting compound and a binder. In an embodiment of the present invention, the electron-accepting compound is the main color developer, and the electron-accepting compound is known electron-accepting compounds including inorganic compounds such as activated clay, kaolin, clay and other substances; And organic compounds such as aromatic carboxylic acid metal salts, carboxylated terpene phenol resin metal salts, phenol resins, salicylate and derivatives thereof, and the like.

The binder of the color development layer 225 serves to improve the adhesion of the electron-accepting compound to the color development film substrate 223. The binder suitable for the color development layer 225 of the present invention is composed of one or more of the following water-soluble binders including, but not limited to, SBR, acrylic latex, PVA, gum arabic, gelatin, CMC, and the like.

3 is a flowchart of a method of manufacturing a color developing film according to an embodiment of the present invention. As shown in Fig. 3, according to an embodiment of the present invention, in step S310, various slurries used to form a chromogenic film, that is, a chromogenic film material (L), are prepared. The slurry includes at least an undercoat layer slurry, an uneven structure layer slurry, and a color developing layer slurry. Step S310 includes dissolving the aqueous resin in water, adding an auxiliary agent and stirring well, to prepare an undercoat layer slurry to be used later. Step S310 further includes a step of preparing a slurry for an uneven structure layer to be used later by adding a reactive diluent to the UV resin and stirring well, adding a photoinitiator or an auxiliary agent and stirring well. Step S310 further comprises a step of preparing a microcapsule and a step of making a color developing layer slurry, and the step of preparing the microcapsule includes emulsifying an oil-water mixture and forming a wall material of the microcapsules. . The oil phase of the oil-water mixture consists of at least an electron-donating colorless dye precursor solution and a reactive monomer for synthesizing the wall material of the microcapsules, and the aqueous phase of the oil-water mixture consists of at least an emulsifier and water. The emulsification process may employ a known emulsification method such as a mechanical stirring emulsification method, a homogeneous emulsification method, an ultrasonic emulsification method, a membrane emulsification method, and the like. In an embodiment according to the invention, the emulsion is preferably prepared by means of a membrane emulsification method. Thereafter, an aqueous solution of a curing agent is added to the emulsion, stirred well, and then heated to 50° C. and reacted for 4 hours to form a microcapsule dispersion. The step of preparing the color developing layer slurry is to add a binder and water to the microcapsule dispersion. And stirring well to form a slurry for a color developing layer to be used later.

In step S320, the undercoat layer is applied on the substrate by a known coating method such as wire bar coating, gravure coating, extrusion coating, reverse roll coating, and the like, and then dried.

In step S330, the wet coating layer of the uneven structure layer is applied on the undercoat layer by a known coating method such as wire bar coating, gravure coating, extrusion coating, reverse roll coating, and the like, to obtain an uneven structure layer.

In step S340, the color developing layer is applied on the uneven structure layer by a known coating method such as slide coating, curtain coating, etc., and then dried to obtain the color developing film material of the present invention.

4 is a flow chart of a method of manufacturing a pressure test film according to an embodiment of the present invention. As shown in FIG. 4, the method of manufacturing the pressure test film is substantially the same as the method of manufacturing the color developing film shown in FIG. 3 except for steps S410, S450, and S460. See. In addition, step S410 of the method for manufacturing the pressure test film shown in FIG. 4 includes the operation of step S310 shown in FIG. 3. In an embodiment according to the present invention, step S410 further comprises the step of preparing a slurry for forming a developer film material, said slurry comprising at least a developer layer slurry. The chromogenic layer slurry to be used later is pre-dispersed by adding activated clay to water and stirring, and then sand milling the resulting mixture using a sand mill to obtain an activated clay aqueous dispersion, and finally adding a binder and stirring. Is obtained.

In addition, in step S450, the color development layer is applied on the substrate by a known coating method such as wire bar coating, gravure coating, extrusion coating, reverse roll coating, and the like, and then dried to obtain a color developing film material.

In step S460, the obtained color-developing film material and color-development film material are then bonded or temporarily bonded when they are used to form a pressure test film.

In the embodiment according to the present invention, the task added in step S410 as shown in 4, except for the task in step S310 as shown in Figure 3, and the task in step S450 as shown in Figure 4 are combined with each other It should be noted that this can form a method of manufacturing the chromogenic film material.

Examples of pressure test films according to the invention

The present invention is further described below with reference to specific embodiments, but the present invention is not limited thereto.

(Example 1)

Preparation of undercoat layer slurry

SBR 6 kg

PVA217 (10%) 10 kg

water 84 kg

After adding 6 kg of SBR and 10 kg of 10% PVA217 aqueous solution to 84 kg of water, the resulting mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of coating solution for uneven structure layer

Urethane acrylate 40 kg

Epoxy acrylate 20 kg

PET3A 25 kg

DPHA 15 kg

184 3 kg

TPO 3 kg

After adding 20 kg of epoxy acrylate to 40 kg of urethane acrylate and stirring well, 25 kg of PET3A and 15 kg of DPHA were sequentially added and stirred well, finally 184 3 kg and 3 kg of TPO were added and stirred well. A slurry of an uneven structure layer for later use is obtained.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

Diisopropyl naphthalene 60 kg

CVL 3.0 kg

BLMB 2.4 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 12 kg

Methyl ethyl ketone 5 kg

After adding 3 kg of CVL and 2.5 kg of BLMB to a mixture of 60 kg of diisopropyl naphthalene and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and then trimethyl of hexamethylene diisocyanate in the dye solution 12 kg of an olpropane adduct was added and stirred well to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA217 aqueous solution (10%) 40 kg

40 kg of a 10% PVA217 aqueous solution was added to 60 kg of water, and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Triethylene tetramine 5 kg

water 20 kg

By adopting the membrane emulsification method, the aqueous solution is selected as the continuous phase of the membrane emulsifier and By choosing an oily solution as the dispersed phase After obtaining the microcapsule emulsion, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under stirring, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%. Thus, a microcapsule dispersion containing an electron-donating colorless dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and the color developing layer to be used later A dispersion is obtained.

Preparation of Developable Layer Dispersion

water 30 kg

Activated clay 10 kg

SBR 2 kg

gelatin 2 kg

After adding 10 kg of activated clay to 30 kg of water, and pulverizing and dispersing the resulting mixture with a sand mill to obtain an aqueous dispersion of activated clay, 2 kg of SBR and 2 kg of gelatin were added and stirred well, and the Developing layer dispersion to be used later To obtain.

On a 75 µm PET substrate, a 0.5 µm undercoat layer and an uneven structure layer were sequentially applied using a wire bar coater, and a 12 µm color developing layer using a slide coater, followed by drying and rewinding. A color developing film material for the pressure test film of the invention is obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a chromogenic film material for the pressure test film of the present invention. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

(Example 2)

Preparation of undercoat layer slurry

SBR 6 kg

PVA217 (10%) 10 kg

water 84 kg

After adding 6 kg of SBR and 10 kg of 10% PVA217 aqueous solution to 84 kg of water, the mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of uneven structure layer coating solution

Urethane acrylate 40 kg

Epoxy acrylate 20 kg

PET3A 22 kg

DPHA 18 kg

907 3 kg

TPO 3 kg

After adding 20 kg of epoxy acrylate to 40 kg of urethane acrylate and stirring well, 22 kg of PET3A and 18 kg of DPHA were sequentially added and stirred well, and 3 kg of 907 and 3 kg of TPO were added and stirred well enough to later A slurry of the uneven structure layer to be used is obtained.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

Diisopropyl naphthalene 60 kg

CVL 4.4 kg

BLMB 3.6 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 10 kg

Methyl ethyl ketone 5 kg

After adding 4.4 kg of CVL and 3.6 kg of BLMB to a mixture of 60 kg of diisopropyl naphthalene and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and trimethylol of hexamethylene diisocyanate in the dye solution 10 kg of a propane adduct was added and stirred well enough to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA205 aqueous solution (10%) 40 kg

40 kg of a 10% PVA205 aqueous solution was added to 60 kg of water and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Triethylene tetramine 5 kg

water 20 kg

By adopting the membrane emulsification method, the aqueous solution is selected as the continuous phase of the membrane emulsifier and the oily solution is selected as the dispersed phase to obtain a microcapsule emulsion. Thereafter, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under stirring, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%, and electron-donating colorless A microcapsule dispersion containing the dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and color development to be used later A layer dispersion is obtained.

Preparation of Developable Layer Dispersion

water 30 kg

Activated clay 10 kg

SBR 2 kg

gelatin 2 kg

10 kg of activated clay was added to 30 kg of water, and the resulting mixture was pulverized and dispersed with a sand mill to obtain an aqueous dispersion of activated clay, and then 2 kg of SBR and 2 kg of gelatin were added and stirred well, a developing layer to be used later A dispersion is obtained.

On a 75 µm PET substrate, a 0.5 µm undercoat layer and an uneven structure layer were sequentially applied using a wire bar coater, and a 12 µm color developing layer using a slide coater, followed by drying and rewinding. A color developing film material for the pressure test film of the invention is obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a chromogenic film material for the pressure test film of the present invention. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

(Example 3)

Preparation of undercoat layer slurry

SBR 5 kg

PVA117 (10%) 15 kg

water 80 kg

After adding 5 kg of SBR and 15 kg of 10% PVA117 aqueous solution to 80 kg of water, the mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of uneven structure layer coating solution

Urethane acrylate 40 kg

Epoxy acrylate 20 kg

TPGDA 25 kg

DPHA 15 kg

184 3 kg

TPO 3 kg

After adding 20 kg of epoxy acrylate to 40 kg of urethane acrylate and stirring well, 25 kg of TPGDA and 15 kg of DPHA were sequentially added and stirred well, and 3 kg of 184 and 3 kg of TPO were added and stirred well enough to later A slurry of the uneven structure layer to be used is obtained.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

1-phenyl-1-dimethylphenylethane 60 kg

CVL 1.5 kg

BLMB 1.2 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 8 kg

Methyl ethyl ketone 5 kg

After adding 1.5 kg of CVL and 1.2 kg of BLMB to a mixture of 60 kg of 1-phenyl-1-dimethylphenylethane and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and hexamethylene was added to the dye solution. 8 kg of a trimethylolpropane adduct of diisocyanate was added and stirred well enough to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA217 aqueous solution (10%) 40 kg

40 kg of a 10% PVA217 aqueous solution was added to 60 kg of water, and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Hexamethylene diamine 4 kg

water 20 kg

By adopting the membrane emulsification method, the aqueous solution is selected as the continuous phase of the membrane emulsifier and the oily solution is selected as the dispersed phase to obtain a microcapsule emulsion. Thereafter, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under stirring, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%, and electron-donating colorless A microcapsule dispersion containing the dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and color development to be used later A layer dispersion is obtained.

Preparation of Developable Layer Dispersion

water 30 kg

Activated clay 10 kg

SBR 2 kg

gelatin 2 kg

10 kg of activated clay was added to 30 kg of water, and the resulting mixture was pulverized and dispersed with a sand mill to obtain an aqueous dispersion of activated clay, and then 2 kg of SBR and 2 kg of gelatin were added and stirred well, a developing layer to be used later A dispersion is obtained.

On a 75 µm PET substrate, a 0.5 µm undercoat layer and an uneven structure layer were sequentially applied using a wire bar coater, and a 12 µm color developing layer using a slide coater, followed by drying and rewinding. A color developing film material for the pressure test film of the invention is obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a chromogenic film material for the pressure test film of the present invention. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

(Example 4)

Preparation of undercoat layer slurry

SBR 5 kg

PVA217 (10%) 15 kg

water 80 kg

After adding 5 kg of SBR and 15 kg of 10% PVA217 aqueous solution to 80 kg of water, the mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of uneven structure layer coating solution

Urethane acrylate 35 kg

Epoxy acrylate 25 kg

PET3A 20 kg

PET4A 20 kg

184 3 kg

907 3 kg

After adding 25 kg of epoxy acrylate to 35 kg of urethane acrylate and stirring well, 20 kg of PET3A and 20 kg of PET4A were sequentially added and stirred well, and 3 kg of 184 and 3 kg of 907 were added and stirred well enough to later A slurry of the uneven structure layer to be used is obtained.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

Diisopropyl naphthalene 60 kg

CVL 3.0 kg

BLMB 2.4 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 7.5 kg

Methyl ethyl ketone 5 kg

After adding 3.0 kg of CVL and 2.4 kg of BLMB to a mixture of 60 kg of diisopropyl naphthalene and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and trimethylol of hexamethylene diisocyanate in the dye solution 7.5 kg of propane adduct was added and stirred well enough to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA217 aqueous solution (10%) 40 kg

40 kg of a 10% PVA217 aqueous solution was added to 60 kg of water and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Triethylene tetramine 4 kg

water 20 kg

By adopting the membrane emulsification method, the aqueous solution is selected as the continuous phase of the membrane emulsifier and the oily solution is selected as the dispersed phase to obtain a microcapsule emulsion. Thereafter, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under agitation, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%, and electron-donating A microcapsule dispersion containing a colorless dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and color development to be used later A layer dispersion is obtained.

Preparation of Developable Layer Dispersion

water 30 kg

Activated clay 10 kg

SBR 2 kg

gelatin 2 kg

10 kg of activated clay was added to 30 kg of water, and the resulting mixture was pulverized and dispersed with a sand mill to obtain an aqueous dispersion of activated clay, and then 2 kg of SBR and 2 kg of gelatin were added and stirred well, a developing layer to be used later A dispersion is obtained.

On a 75 µm PET substrate, a 0.5 µm undercoat layer and an uneven structure layer were sequentially applied using a wire bar coater, and a 12 µm color developing layer using a slide coater, followed by drying and rewinding. A color developing film material for the pressure test film of the invention is obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a chromogenic film material for the pressure test film of the present invention. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

(Example 5)

Preparation of undercoat layer slurry

SBR 6 kg

PVA117 (10%) 10 kg

water 84 kg

After adding 6 kg of SBR and 10 kg of 10% PVA117 aqueous solution to 84 kg of water, the mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of uneven structure layer coating solution

Urethane acrylate 30 kg

Epoxy acrylate 30 kg

DPGDA 30 kg

PET4A 10 kg

184 2.5 kg

TPO 4 kg

After adding 30 kg of epoxy acrylate to 30 kg of urethane acrylate and stirring well, 30 kg of DPGDA and 10 kg of PET4A were sequentially added and stirred well, and 2.5 kg of 184 and 4 kg of TPO were added and sufficiently well stirred. A slurry of the uneven structure layer to be used is obtained.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

1-phenyl-1-dimethylphenylethane 60 kg

CVL 2.0 kg

BLMB 1.6 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 12 kg

Methyl ethyl ketone 5 kg

After adding 2.0 kg of CVL and 1.6 kg of BLMB to a mixture of 60 kg of 1-phenyl-1-dimethylphenylethane and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and hexamethylene was added to the dye solution. 12 kg of the trimethylolpropane adduct of diisocyanate was added and stirred well enough to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA217 aqueous solution (10%) 40 kg

40 kg of a 10% PVA217 aqueous solution was added to 60 kg of water and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Triethylene tetramine 5 kg

water 20 kg

By adopting the membrane emulsification method, the aqueous solution is selected as the continuous phase of the membrane emulsifier and the oily solution is selected as the dispersed phase to obtain a microcapsule emulsion. Thereafter, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under stirring, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%, and electron-donating colorless A microcapsule dispersion containing the dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and color development to be used later A layer dispersion is obtained.

Preparation of Developable Layer Dispersion

water 30 kg

Activated clay 10 kg

SBR 2 kg

gelatin 2 kg

10 kg of activated clay was added to 30 kg of water, and the resulting mixture was pulverized and dispersed with a sand mill to obtain an aqueous dispersion of activated clay, and then 2 kg of SBR and 2 kg of gelatin were added and stirred well, a developing layer to be used later A dispersion is obtained.

On a 75 µm PET substrate, a 0.5 µm undercoat layer and an uneven structure layer were sequentially applied using a wire bar coater, and a 12 µm color developing layer using a slide coater, followed by drying and rewinding. A color developing film material for the pressure test film of the invention is obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a chromogenic film material for the pressure test film of the present invention. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

Comparison with conventional pressure test film

(Comparative Example 1)

Preparation of undercoat layer slurry

SBR 6 kg

PVA217 (10%) 10 kg

water 84 kg

After adding 6 kg of SBR and 10 kg of 10% PVA217 aqueous solution to 84 kg of water, the mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

Diisopropyl naphthalene 60 kg

CVL 5.0 kg

BLMB 3.8 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 12 kg

Methyl ethyl ketone 5 kg

After adding 5.0 kg of CVL and 3.8 kg of BLMB to a mixture of 60 kg of diisopropyl naphthalene and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and trimethylol of hexamethylene diisocyanate in the dye solution 12 kg of a propane adduct was added and stirred well enough to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA217 aqueous solution (10%) 40 kg

40 kg of a 10% PVA217 aqueous solution was added to 60 kg of water and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Triethylene tetramine 5 kg

water 20 kg

The mechanical emulsification method was adopted, the aqueous solution was selected as the continuous phase, and the oily solution was added while stirring at a high speed of 750 rpm and emulsified for 10 minutes to obtain a microcapsule emulsion. Thereafter, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under agitation, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%, and electron-donating A microcapsule dispersion containing a colorless dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and color development to be used later A layer dispersion is obtained.

Preparation of Developable Layer Dispersion

water 30 kg

Activated clay 10 kg

SBR 2 kg

gelatin 2 kg

10 kg of activated clay was added to 30 kg of water, and the resulting mixture was pulverized and dispersed with a sand mill to obtain an aqueous dispersion of activated clay, and then 2 kg of SBR and 2 kg of gelatin were added and stirred well, a developing layer to be used later A dispersion is obtained.

On a 75 µm PET substrate, a 0.5 µm undercoat layer was sequentially applied using a wire bar coater, and a 12 µm color developing layer was sequentially applied using a slide coater, followed by drying and rewinding the color developing film of the pressure test film. Material is obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a color developing film material for a pressure test film. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

(Comparative Example 2)

Preparation of undercoat layer slurry

SBR 5 kg

PVA217 (10%) 15 kg

water 80 kg

After adding 5 kg of SBR and 15 kg of 10% PVA217 aqueous solution to 80 kg of water, the mixture was stirred well to obtain an undercoat layer slurry to be used later.

Preparation of uneven structure layer coating solution

Urethane acrylate 40 kg

Epoxy acrylate 20 kg

PET3A 25 kg

DPHA 15 kg

184 3 kg

TPO 3 kg

After adding 20 kg of epoxy acrylate to 40 kg of urethane acrylate and stirring well, 25 kg of PET3A and 15 kg of DPHA were sequentially added and stirred well, and 3 kg of 184 and 3 kg of TPO were added and stirred well enough to later A slurry of the uneven structure layer to be used is obtained.

Preparation of microcapsules and dispersions thereof

Preparation of oily solution:

Diisopropyl naphthalene 60 kg

CVL 6.5 kg

BLMB 5.4 kg

Trimethylolpropane adduct of hexamethylene diisocyanate 12 kg

Methyl ethyl ketone 5 kg

After adding 6.5 kg of CVL and 5.4 kg of BLMB to a mixture of 60 kg of diisopropyl naphthalene and 5 kg of methyl ethyl ketone, the mixture was stirred to completely dissolve to obtain a dye solution for later use, and trimethylol of hexamethylene diisocyanate in the dye solution 12 kg of a propane adduct was added and stirred well enough to obtain an oily solution to be used later.

Preparation of aqueous solution:

water 60 kg

PVA217 aqueous solution (10%) 40 kg

40 kg of a 10% PVA217 aqueous solution was added to 60 kg of water and stirred well to obtain an aqueous solution to be used later.

Hardener aqueous solution

Triethylene tetramine 5 kg

water 20 kg

The mechanical emulsification method was adopted, the aqueous solution was selected as the continuous phase, and the oily solution was added while stirring at high speed of 950 rpm and emulsified for 10 minutes to obtain a microcapsule emulsion. Thereafter, an aqueous curing agent solution was added to the obtained emulsion, heated to 50° C. under stirring, reacted continuously for 4 hours, cooled to room temperature, and water was added to adjust the solid content to 30%, and electron-donating colorless A microcapsule dispersion containing the dye precursor is obtained.

Preparation of color developing layer dispersion

Microcapsule dispersion (30%) 50 kg

PVA205 aqueous solution (10%) 20 kg

CMC aqueous solution (10%) 30 kg

water 33 kg

20 kg of 10% PVA205 aqueous solution and 30 kg of 10% CMC aqueous solution were sequentially added to 50 kg of 30% microcapsule dispersion, and after stirring well, 33 kg of water was added to adjust the solid content to 15%, and color development to be used later A layer dispersion is obtained.

On a 75 µm PET substrate, a 0.5 µm undercoat layer and an uneven structure layer were sequentially applied using a wire bar coater, and a 12 µm color developing layer using a slide coater, followed by drying and rewinding. A color developing film material for the test film was obtained.

On a 75 µm PET substrate, a 13 µm developing layer was applied using a wire bar coater, followed by drying and rewinding to obtain a color developing film material for a pressure test film. The obtained color developing film material and the color developing film material are superimposed in a manner facing each other to test their performance.

Example performance test data D50/㎛ span A/㎛ Low temperature color application Test sensitivity Appearance uniformity Example 1 8.3 0.71 5.8 A A A Example 2 10.7 1.02 7.5 A A A Example 3 6.1 0.62 4.4 A A A Example 4 8.9 0.75 5.8 A A A Example 5 7.4 0.72 3.7 A A A Comparative Example 1 16.4 1.53 / B C C Comparative Example 2 8.5 1.21 5.8 C B B

In the above table, the test method for each characteristic is as follows:

1. Test method of particle size distribution

A microcapsule dispersion is prepared, and the particle size distribution D50 and span of the particle size distribution of the microcapsule dispersion are measured using a BT-9300ST laser particle size analyzer.

2. Test method of A value

A sheet coated with an undercoat layer and an uneven structure layer is prepared. The shortest distance between adjacent convex portions in each of the five groups of adjacent convex portions was measured with an electron microscope (SEM), and the average value was calculated to obtain A value.

3. Method to test color application at low temperature

The pressure test film obtained above was divided into two groups of group I and group II, and the following tests were carried out at 25°C and 10°C, respectively. First, after cutting the microcapsules into a size of 3 cm × 3 cm, a color developing sheet containing an electron-donating colorless dye precursor and a color developing sheet containing an electron-accepting compound are overlapped in such a manner that the coating faces each other, Place it between the planes. Applying full-coverage pressure to the entire sheet creates a color in saturation. Thereafter, after separating the two overlapping sheets, the density value OD1 of the color-developed part on the color development sheet was measured using an X.rite colorimeter, and the initial density value OD0 of the color-developed part on the color development sheet. Was measured in the same way, and the actual color developing density OD was obtained using OD1-OD0. The difference ΔOD in color development density between the two groups under different temperature and same pressure can be obtained using ODI-ODII.

Evaluation standard

A (1.5≤OD, ΔOD≤0.2): The dye does not precipitate at 10°C, and the film can be used normally.

B (1.3≤OD<1.5, 0.2<ΔOD≤0.4): The dye is slightly precipitated at 10℃, and it does not affect the use.

C (OD<1.3, ΔOD>0.4): At 10°C, the dye is severely precipitated and the film cannot be used.

4. Test method of test sensitivity

After cutting the pressure test film obtained above into a size of 20 cm × 20 cm, the color developing sheet containing the electron-donating colorless dye precursor and the color developing sheet containing the electron-accepting compound were overlapped in such a manner that the coatings face each other. Place it between two smooth planes. After applying full-coverage pressure to the entire sheet to create color, the two overlapping sheets are separated. The color development density ODi of five different areas for the chromogenic sheet was randomly measured with an X.rite colorimeter to calculate the average value OD and the maximum error value ΔOD, and divide the ΔOD by OD to obtain a percentage value X.

A (X≤5%): boundaries are clear and distinguishable, test sensitivity is high;

B (5%<X≤10%): boundary definition is tolerated, test sensitivity is tolerated;

C (10%<X): The boundary is ambiguous and the test sensitivity is poor.

5. Appearance uniformity test method

The pressure test film obtained above was cut into a size of 10 cm x 10 cm, five regions were randomly selected, and the appearance of the microcapsules was observed using an electron microscope.

A: Large and small particles are uniformly spread without aggregation.

B: Large and small particles are basically uniformly spread without apparent aggregation.

C: Large and small particles do not spread uniformly, and small particles are close to large particles to form an island-like structure.

As can be seen from the test results in the above table, the color development applicability, test sensitivity, and appearance uniformity of the examples at low temperatures are all superior to those of the comparative examples, so that the pressure test film produced by the technical solution of the present invention is used in a low temperature environment. It can meet the pressure distribution test of high sensitivity and high resolution.

The invention is not limited to the embodiments shown in the drawings and described in the description of the invention. The foregoing description is for illustrative purposes only and does not limit the scope of the invention. Many variations from the above description and falling within the spirit and scope of the invention will be apparent.

Claims (10)

A substrate configured to apply another layer thereon to form a color developing film;
An uneven structure layer formed on the substrate; And
A color developing layer applied on the uneven structure layer and comprising microcapsules containing an electron-donating colorless dye precursor therein, wherein the electron-donating colorless dye precursor is in contact with an electron-accepting compound to form a color As a color developing film containing;
When the chromogenic film is under pressure, the uneven structure layer compresses the chromogenic layer so that the microcapsules in the chromogenic layer are broken and the electron-donating colorless dye precursor is released. The method according to claim 1,
A color developing film further comprising an undercoat layer configured to stably support the uneven structure layer on the substrate between the substrate and the uneven structure layer. The method according to claim 1 or 2,
The uneven structure layer has at least two convex portions, and the linear distance L between the tops of two adjacent convex portions satisfies the following relationship: D50×0.2≦L≦D50×0.8, where D50 is 50% of the microcapsules The color developing film showing the particle diameter corresponding to the cumulative particle size distribution of. The method according to claim 1 or 2,
The uneven structure layer is a color developing film formed of a UV resin. The method according to claim 1 or 2,
The convex portion on the uneven structure layer is a color developing film in the form of a cylinder, a cone, a rectangular parallelepiped, or a regular cube. The method according to claim 1 or 2,
The colored film having a pointed upper portion of the convex portion on the uneven structure layer. The method according to claim 2,
The undercoat layer is made of a water-based resin by coating, and the water-based resin is preferably polyvinyl alcohol or styrene-butadiene rubber. A color developing film layer containing the color developing film of any one of claims 1 to 7; And
A pressure test film comprising; a chromogenic film layer containing a chromogenic material of an electron-accepting compound. Adding a reactive diluent to the UV resin and stirring well, adding a photoinitiator or an auxiliary agent, and stirring well, thereby preparing a slurry for an uneven structure layer;
After preparing an oil phase and an aqueous phase containing an electron-donating colorless dye precursor, and adding the oil phase to the aqueous phase by adopting a film emulsification method to form an emulsion, a curing agent was added to the emulsion and stirred well, and the mixture was brought to 50°C. Heating and reacting for 4 hours to obtain a microcapsule dispersion, adding a binder and water to the microcapsule dispersion and stirring well to prepare a color developing layer slurry; And
The method for producing a color developing film according to any one of claims 1 to 7 comprising a step of sequentially applying the uneven structure layer slurry and the color developing layer slurry on a substrate to form a color developing film applicable to the pressure test film. Adding a reactive diluent to the UV resin and stirring well, adding a photoinitiator or an auxiliary agent, and stirring well, thereby preparing a slurry for an uneven structure layer;
After preparing an oil phase and an aqueous phase containing an electron-donating colorless dye precursor, and adding the oil phase to the aqueous phase by adopting a film emulsification method to form an emulsion, a curing agent was added to the emulsion and stirred well, and the mixture was brought to 50°C. Heating and reacting for 4 hours to obtain a microcapsule dispersion, adding a binder and water to the microcapsule dispersion and stirring well to prepare a color developing layer slurry;
Activated clay is added to water and stirred to pre-disperse, and then sand milled with a sand mill to form an activated clay aqueous dispersion, and finally, a binder is added to the activated clay aqueous dispersion and stirred well to prepare a Developable layer slurry. Step to do;
The uneven structure layer slurry and the color developing layer slurry are sequentially applied on the substrate to form a color developing film applicable to the pressure test film, and the color developing layer slurry is applied on the substrate to form a color developing film applicable to the pressure test film. Forming; And
The method of manufacturing a pressure test film of claim 8 comprising; forming a pressure test film by combining the color developing film and the color developing film.

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