Fluidity improvement device and fluidity improvement method for emulsion material

Abstract

To provide an emulsion material fluidity improvement device and fluidity improvement method for facilitating application development to an object member by improving the fluidity of an emulsion material without changing a situation of dispersion particles of the emulsion material in applying a particle dispersion system emulsion material to the object member.SOLUTION: An injection device 10 is a device for improving fluidity in applying a particle dispersion system emulsion material obtained by dispersing particles to a dispersion medium containing a stabilizer composed of high molecular materials to a prescribed object member, and is provided with an ultrasonic treatment part 12 for adding ultrasonic vibrations to the emulsion material so as to lower viscoelasticity by shear deformation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for improving the fluidity of an emulsion material. More specifically, the present invention relates to an apparatus and a method for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer made of a polymer substance to a predetermined target member.

Background Art

[0002] In adhesives and paints made of an emulsion material of a particle dispersion system in which predetermined particles are dispersed in a dispersion medium, a stabilizer made of a polymer substance for imparting viscoelasticity to the dispersion medium is included in order to prevent precipitation and separation of the particles and to stabilize the dispersed state (see Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when applying and spreading an adhesive or paint made of the emulsion material onto a target member made of a predetermined adherend or coated material, due to the aforementioned viscoelasticity, it is difficult to spread the coating on the target member, and the entry of the adhesive or paint into the fine irregularities of the target member is inhibited, leading to problems such as a decrease in the adhesive strength on the target member and the generation of an uneven coating film.

[0005] The present invention has been devised by paying attention to such problems, and its object is to improve the fluidity of an emulsion material when applying the emulsion material of a particle dispersion system to a target member, making it easier to apply and spread the coating on the target member, without changing the state of the dispersed particles of the emulsion material, and to provide an apparatus and a method for improving the fluidity of the emulsion material.

Means for Solving the Problems

[0006] In order to achieve the above object, the present invention mainly relates to an apparatus for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer made of a polymer substance to a predetermined target member, and the apparatus is configured to include an ultrasonic treatment unit that applies ultrasonic vibration to the emulsion material so as to cause shear deformation.

[0007] Further, there can also be adopted a configuration of an apparatus for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer to a predetermined material to be coated, the apparatus including an ultrasonic treatment unit that applies ultrasonic vibration to the emulsion material so as to reduce the elasticity.

[0008] Furthermore, the present invention relates to a method for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer made of a polymer substance to a predetermined target member, and the method adopts a technique of applying ultrasonic vibration to the emulsion material before coating so as to cause shear deformation.

Advantages of the Invention

[0009] According to the present invention, by applying ultrasonic vibration to the emulsion material of the particle dispersion system, the viscoelasticity of the dispersion medium is reduced without changing the shape, contact state, etc. of the dispersed particles of the emulsion material, and thereby, the fluidity of the emulsion material applied to the target member can be improved. Therefore, in the case of an adhesive of an emulsion material system, more fine particles of the adhesive can enter into the minute irregularities of the adherend as the target member, the adhesion area can be increased, and at the same time, a strong joint portion is formed, so that the adhesion strength at the interface between the adhesive and the adherend is improved. Similarly, in the case of a paint of an emulsion material system, the adhesiveness at the interface between the paint and the material to be coated as the target member is improved.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] FIG. 1 shows a cross-sectional front view for conceptually explaining an injection device to which the present invention is applied, and FIG. 2 shows a side view of the same cross-section of the injection device. Further, FIG. 3(A) shows a cross-sectional view of the injection device in the A-A direction in FIG. 1, and FIG. 3(B) shows a cross-sectional view of the injection device in the B-B direction.

[0013] In each of the above figures, the injection device 10 is a device for applying an emulsion material of a particle dispersion system (hereinafter simply referred to as "emulsion material") in which predetermined particles are dispersed in a predetermined dispersion medium to a predetermined target member, and functions as a fluidity improving device for improving the fluidity of the emulsion material at that time.

[0014] The emulsion material is obtained by dispersing dispersion particles made of solids such as polymers in a dispersion medium made of water or a solvent containing a stabilizer made of a polymer material that prevents aggregation, separation, and precipitation of the particles, and is sprayed by the injection device 10 as an adhesive or a paint. When this emulsion material is applied to a target member that is an adherend or a material to be coated, the dispersion medium evaporates and the solid particles aggregate and solidify, so that it firmly adheres to the surface of the target member, and member joining and coating film formation are performed.

[0015] Here, examples of the adhesive made of the emulsion material include emulsion adhesives such as vinyl acetate emulsion, acrylic emulsion, and epoxy emulsion. Further, examples of the paint made of the emulsion material include emulsion paints such as acrylic emulsion, latex emulsion, silicone emulsion, epoxy emulsion, and polyurethane emulsion.

[0016] Examples of the stabilizer for these emulsion materials include polymer stabilizers such as polyacrylate ester, polymethacrylate ester, polyvinyl alcohol, ethylene polyvinyl alcohol, polyvinyl acetate, ethylene vinyl acetate copolymer, casein, latex, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, EVA (ethylene-vinyl acetate copolymer resin), acrylic resin particles, latex, and casein. That is, these stabilizers exhibit a dispersion action of interacting at the interface with the dispersion medium to uniformly disperse the particles, a surface tension reduction action of reducing the surface tension of the dispersion medium to facilitate the adhesion of the particles to the target member, and a particle surface coating action of covering the surface of the particles to suppress the aggregation of the particles.

[0017] The dispersion particles may be anything as long as the dispersion medium evaporates and the solid particles aggregate and solidify. In the case of an adhesive, for example, polyvinyl acetate, EVA, acrylic resin particles, latex, glass, silica, etc. can be mentioned. In the case of a paint, for example, acrylic resin, latex, silicone, epoxy, polyurethane, etc. can be mentioned.

[0018] The injection device 10 includes a nozzle portion 11 that injects the emulsion material onto a target member to be coated, and an ultrasonic treatment portion 12 that applies ultrasonic vibration to the emulsion material before it is injected from the nozzle portion 11.

[0019] The nozzle portion 11 includes an introduction path 14 for introducing the emulsion material from the outside, an internal flow path 15 connected to the introduction path 14 through which the emulsion material passes, and a discharge port 16 for discharging the emulsion material from the internal flow path 15 to the outside.

[0020] The internal flow path 15 is not particularly limited, but includes an upstream flow path 18 with a circular cross-section that communicates with the introduction path 14, a tapered flow path 19 that is connected to the upstream flow path 18 and has a shape in which the inner diameter gradually decreases from the upstream flow path 18, and a downstream flow path 20 that is connected from the tapered flow path 19 to the discharge port 16 and has a uniform rectangular cross-section smaller than that of the upstream flow path 18.

[0021] The ultrasonic treatment unit 12 has a structure that applies high-frequency vibration to shear-deform the emulsion material in the internal flow path 15 and reduce its viscoelasticity. That is, the ultrasonic treatment unit 12 includes a rectangular flat plate-shaped vibrator 22 disposed in the center of the internal flow path 15 and vibrating in the vertical direction (the vertical direction in FIGS. 1 and 2) along the flow direction of the emulsion material from the introduction path 14 to the discharge port 16, and an ultrasonic oscillator 23 having a known structure for vibrating the vibrator 22.

[0022] The ultrasonic oscillator 23 operates to vibrate the vibrator 22 in the longitudinal direction (the vertical direction in FIG. 2) along the flow direction of the emulsion material in the downstream flow path 20. Here, by applying longitudinal high-frequency vibration to the vibrator 22 disposed at the center of the interior of the downstream flow path 20, which has a rectangular cross-section, continuous shear deformation in the vertical direction in FIGS. 1 and 2 is applied to the fluid-like emulsion material passing through the downstream flow path 20, improving the fluidity of the emulsion material discharged from the discharge port 16 from its original state.

[0023] Also, the distance between the inner wall of the nozzle portion 11 forming the downstream flow path 20 and the vibrator 22 should be made as small as possible, for example, about 5 mm or less. Thereby, vibration attenuation to the emulsion material near the outer periphery of the downstream flow path 20 can be suppressed, and uniform high-frequency vibration can be applied to the emulsion material.

[0024] In addition, by arranging the vibrator 22 at the central portion in the downstream channel 20, vibration can be evenly applied to the emulsion material in the downstream channel 20. Moreover, the balance of the vibration loads applied to both sides of the vibrator 22 is maintained, and failures of components and blockage of the downstream channel 20 can be prevented. The frequency by the ultrasonic treatment unit 12 is appropriately selected according to the characteristics of the material.

[0025] Note that the vibrator 22 in the present invention is not limited to the form of the above-described embodiment, and as long as it can apply shear deformation to the emulsion material before being discharged from the discharge port 16 and improve the fluidity of the emulsion material discharged from the discharge port 16 from the original state, various structures and forms can be adopted. For example, when the downstream channel 20 has a circular cross-section, the vibrator 22 can also be in the form of a round bar arranged along the axial direction of the center of the downstream channel 22.

[0026] In the injection device 10 having the above configuration, ultrasonic vibration is added to the emulsion material before being applied to the target member so as to give continuous shear deformation and reduce viscoelasticity by the longitudinal vibration of the vibrator 22 along the flow direction thereof.

[0027] Next, in order to demonstrate the effect of the ultrasonic treatment in the present invention, the following various tests were conducted.

[0028] First, for a predetermined adhesive and paint, the dynamic viscoelasticities of a sample subjected to the above-described ultrasonic treatment (hereinafter referred to as "treated sample") and a sample not subjected to the ultrasonic treatment (hereinafter referred to as "untreated sample") were measured respectively.

[0029] As the adhesives, Adhesive 1 (Bond Woodworking CH18: manufactured by Konishi Co., Ltd.) and Adhesive 2 (Bond Woodworking Quick Drying: manufactured by Konishi Co., Ltd.) were used. As the paints, Paint 1 (DCM Water-based Hobby Multi-Paint: manufactured by DCM Co., Ltd.) and Paint 2 (DCM Water-based Multi-Purpose Paint: manufactured by DCM Co., Ltd.) were used.

[0030] Also, the ultrasonic treatment was performed as follows. That is, a vibration plate for applying ultrasonic waves was inserted from above into the liquid surface of the samples (adhesives 1 and 2 and paints 1 and 2) placed in the treatment container, and the vibration plate was vibrated in the vertical direction so as to cause high-frequency shear deformation to the samples at an output of 185 W, a frequency of 20 MHz, and for 10 seconds.

[0031] For four types of samples, namely, the treated and untreated samples of adhesives 1 and 2 and paints 1 and 2, a dynamic viscoelasticity test was conducted under the following conditions using a dynamic viscoelasticity measuring device (PZRheo NDS-1000: manufactured by Taihei Co., Ltd.). The storage elastic modulus G´ representing elasticity and the loss elastic modulus G´´ representing viscosity were measured. Here, the temperature condition was 25 °C, the vibration condition was 3 Hz and 10 μm (shear deformation mode), and as the sample shape, the sample width was 1 mm and the plunger area was 216 mm 2 was used.

[0032] The measurement results of the dynamic viscoelasticity of each sample were as shown in the following table.

[0033]

Table 1

[0034] According to the above measurement results, for the two types of adhesives 1 and 2 which are vinyl acetate resin emulsion adhesives, by performing the above-mentioned ultrasonic treatment, a decrease in viscoelasticity was observed in both cases compared with the untreated samples of the same type, and in particular, the storage elastic modulus G´ decreased significantly. Also, for the two types of paints 1 and 2 which are acrylic resin emulsion paints, by performing the above-mentioned ultrasonic treatment, the storage elastic modulus G´ decreased significantly in both cases compared with the untreated samples of the same type.

[0035] In addition, in order to examine other effects of ultrasonic treatment, for the treated samples of Adhesive 2, after freeze-drying, osmium deposition was performed, and scanning electron microscope observation (SEM observation) was carried out using a scanning electron microscope (Regulus8230: manufactured by Hitachi High-Technologies Corporation). As a result, no influence of ultrasonic treatment was observed on the shape of the vinyl acetate resin particles dispersed in Adhesive 2 and the contact state between the particles.

[0036] According to the above experimental results, although a decrease in the elastic modulus of Adhesives 1 and 2 was observed due to ultrasonic treatment, no change in the dispersed particles was recognized. Therefore, it is considered that the cause of the decrease is due to the elastic change of the dispersion medium caused by ultrasonic treatment. Usually, for adhesives and paints composed of emulsion materials, a stabilizer composed of a water-soluble polymer such as polyvinyl alcohol or ethylene polyvinyl alcohol is dissolved in the water of the dispersion medium to impart viscoelasticity, prevent aggregation, separation, and precipitation of the dispersed particles, and stabilize the emulsion state. However, by subjecting adhesives and paints composed of emulsion materials to the above-described ultrasonic treatment, it is presumed that the intermolecular network formed between the water-soluble polymers in the dispersion medium is weakened and the elasticity is decreased.

[0037] Next, an adhesive performance evaluation test was conducted for each of the treated sample and the untreated sample of the above-mentioned Adhesive 2. The adhesive performance evaluation test here was carried out in accordance with the compression shear adhesion strength test of JIS K6852. In this test, first, as test pieces, two pieces of Macaca (true birch) sawn timber (1515 mm × 2525 mm × 35 mm, super-finished planed surface treatment) were adhered at a bonding surface of 25 mm × 25 mm, and the pressure was maintained indoors for 2 weeks to produce an adhesive test piece. Then, the adhesive test piece was attached to a specified compression shear test jig, and a compression shear test was carried out at a test speed of 33 mm / sec using a universal testing machine (AGX100 kN V: manufactured by Shimadzu Corporation), and the results shown in the following table were obtained.

[0038]

Table 2

[0039] According to the above test results, in the test piece as the adherend coated with the ultrasonically treated adhesive 2, the fracture deformation and fracture strength increased by about 13 - 15% compared with the case of using the untreated adhesive 2. Also, at the time of fracture, neither the destruction of the adherend nor the peeling of the adhesive occurred. In both cases, deformation and fracture occurred in the adhesive part, and it was found that the adhesive and the adherend were joined with a strength greater than that of the adhesive itself when not treated with ultrasound.

[0040] Furthermore, for each of the treated samples and untreated samples of Paint 1 and Paint 2, a coating film performance evaluation test was conducted. The coating film performance evaluation test here was carried out according to the coating film adhesion test of JIS K5600 - 5 - 6 (ISO 2409). That is, the treated samples and untreated samples of the two types of acrylic emulsion paints of the above - mentioned Paint 1 and Paint 2 were brush - painted once on one side of an aluminum plate (150 mm × 100 mm × 1 mm) in an area of 100 mm × 100 mm, dried at room temperature for 10 days, and then subjected to the coating film adhesion test. In this test, by the vertical and horizontal cutting (cross - cut) of the predetermined coating film surface, it was evaluated which adhesion classification in the following table (extracted from the JIS standard form) each sample corresponded to.

[0041]

Table 3

[0042] The results of the above coating film performance evaluation test were as shown in the following table.

Table 4

[0043] According to the above coating film performance evaluation test, for both Paint 1 and Paint 2, in the samples where ultrasonic treatment was carried out, the adhesion classification changed in the direction of improving the coating film performance compared with the untreated samples of the same type. This is considered to be due to the decrease in the elastic modulus of the paint, which makes it easier for the paint to enter the fine irregularities on the painted surface, increasing the adhesion of the paint to the painted surface.

[0044] From the above test results, it was demonstrated that the adhesives and paints composed of the emulsion materials of the particle dispersion systems subjected to the ultrasonic treatment have the following effects. That is, the adhesives and paints subjected to the ultrasonic treatment have improved fluidity due to the decrease in the elastic modulus of the dispersion medium. In the case of the adhesives, the adhesive strength at the interface between the adhesive and the adherend is improved, and in the case of the paints, the adhesiveness at the interface between the paint and the material to be coated is improved.

[0045] Note that the configuration of each part of the device in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as they exhibit substantially the same function.

Explanation of Reference Numerals

[0046] 10 Injection device (fluidity improvement device) 11 Nozzle part 12 Ultrasonic treatment part 14 Introduction path 15 Internal flow path 16 Discharge port 22 Vibrator 23 Ultrasonic oscillator

Claims

1. An apparatus for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer made of a polymer substance to a predetermined target member, comprising: An apparatus for improving the fluidity of an emulsion material, characterized in that it is provided with an ultrasonic treatment unit that applies ultrasonic vibration to the emulsion material so as to cause shear deformation.

2. An apparatus for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer to a predetermined coated material, comprising: An apparatus for improving the fluidity of an emulsion material, characterized in that it is provided with an ultrasonic treatment unit that applies ultrasonic vibration to the emulsion material so as to reduce its elasticity.

3. The apparatus for improving the fluidity of an emulsion material according to claim 2, characterized in that the ultrasonic treatment unit applies ultrasonic vibration to the emulsion material so as to reduce its viscosity.

4. The apparatus for improving the fluidity of an emulsion material according to claim 1, characterized in that the emulsion material is an adhesive or a paint.

5. Further comprising a nozzle unit for injecting the emulsion material, The nozzle unit includes an introduction path for introducing the emulsion material, an internal flow path connected to the introduction path through which the emulsion material passes, and a discharge port for discharging the emulsion material from the internal flow path to the outside. The apparatus for improving the fluidity of an emulsion material according to claim 1 or 2, characterized in that the ultrasonic treatment unit is disposed at the center within the internal flow path, and includes a vibrator that vibrates along the flow direction of the emulsion material from the introduction path to the discharge port, and an ultrasonic oscillator that vibrates the vibrator.

6. The apparatus for improving the fluidity of an emulsion material according to claim 5, characterized in that the vibrator is disposed such that the distance from the inner wall of the nozzle unit forming the internal flow path is 5 mm or less.

7. A method for improving the fluidity when applying an emulsion material of a particle dispersion system in which particles are dispersed in a dispersion medium containing a stabilizer made of a polymer substance to a predetermined target member, comprising: A method for improving the fluidity of an emulsion material, characterized in that ultrasonic vibration is applied to the emulsion material before application so as to cause shear deformation.

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