TWI876499B - Stretchable object with play-of-color effect and method for making the same - Google Patents

Abstract

A method for making a stretchable object with a play-of-color effect includes: providing a first solution containing a solvent and a plurality of microparticles; replacing the solvent with a reactive solution containing a first reactant; adding a second reactant having a boiling point higher than that of the first reactant, and volatilizing the first reactant; adding an initiator and then standing to allow self-assembly to occur; and crosslinking and curing the second reactant to obtain a stretchable object with a play-of-color effect. In this case, the addition of a second reactant is used to make the stretchable object flexible or elastic, and the uniform dispersion of the microparticles in the solution facilitates self-assembly, so that the stretchable object has a play-of-color effect. In addition, this case also provides a stretchable object with a play-of-color effect.

Description

Stretchable object with play-of-color effect and method for making the same

The present invention relates to a plastic product and a manufacturing method thereof, in particular to a stretchable object with play-of-color effect and a manufacturing method thereof.

In order to meet consumers' pursuit and diversification of the appearance of electronic products or wearable devices, some companies choose to use artificial opal as the shell or decoration of the product to achieve an aesthetic effect. The artificial opal has a photonic crystal structure, so when the light beam irradiates the artificial opal from different angles, different diffraction paths will be generated based on the different positions of the photon energy gap of the photonic crystal structure, and different color changes will be presented to the outside, with a play-of-color effect. At present, the production method of artificial opal is generally as follows: preparing a reaction solution containing a plurality of silica particles with a particle size between 250nm and 500nm; leaving the reaction solution for several weeks to several months to allow the silica particles to naturally settle and rearrange themselves; removing the solvent in the reaction solution by drying to obtain a semi-finished product; and calcining the semi-finished product to obtain an artificial opal with play-of-color effect.

However, the time and cost of producing the artificial opal is too high, and the artificial opal is usually hard and has low processability, which makes it difficult to be configured on products with various structural designs.

Therefore, the purpose of the present invention is to provide a method for manufacturing a stretchable object with a play-of-color effect, which can significantly reduce time costs and the stretchable object obtained has good processability.

Therefore, the method for making a stretchable object with play-of-color effect of the present invention includes step (a), step (b), step (c), step (d), and step (e).

The step (a) is to provide a first solution containing a solvent and a plurality of dispersed particles with modified surfaces.

The step (b) is to replace the solvent of the first solution with a reactive solution to obtain a second solution, wherein the reactive solution contains a first reactant, the particles are uniformly dispersed in the first reactant, and the first reactant contains a reactive monomer.

The step (c) is to add a second reactant having a boiling point higher than that of the first reactant to the second solution to obtain a third solution, and to volatilize the first reactant from the third solution to obtain a fourth solution, wherein the second reactant contains at least one of a reactive monomer and a reactive oligomer.

The step (d) is to add an initiator to the fourth solution and allow the solution to stand, so that the second reactant and the microparticles are self-assembled to obtain a crystallization solution.

The step (e) is to crosslink and solidify the second reactant of the crystallization solution to obtain a stretchable object with play-of-color effect.

Another object of the present invention is to provide a stretchable object with play-of-color effects.

Therefore, the stretchable object with play-of-color effect of the present invention includes a base and an appearance piece.

The appearance piece is stretchable and has a play-of-color effect, is coated or embedded on the surface of the substrate, and includes a stretchable body obtained by cross-linking and solidifying a reactive substance, and a plurality of particles dispersed in the stretchable body, and the reactive substance is selected from at least one of a reactive monomer and a reactive oligomer.

Another object of the present invention is to provide a stretchable object with play-of-color effects.

Therefore, the stretchable object with play-of-color effect of the present invention comprises a stretchable body and a plurality of particles.

The stretchable body is obtained by cross-linking and solidifying reactive substances and has stretchability.

The particles are dispersed in the stretchable body.

The effect of the present invention is that the boiling point difference between the first reactant and the second reactant is utilized to replace the first reactant in the second solution with the second reactant to obtain the third solution, so that the particles can still be dispersed in the second reactant and do not tend to agglomerate, which is conducive to the arrangement of self-assembled crystals, and the material selection of the second reactant is more flexible, which is conducive to the production of the appearance piece with stretchability and play-of-color effects, and has good processability, while greatly reducing the process time.

Before the present invention is described in detail, it should be noted that similar components are represented by the same number in the following description. The relevant technical content, features and effects of the present invention will be clearly presented in the following detailed description of the embodiments with reference to the drawings. In addition, it should be noted that the drawings of the present invention only represent the relative relationship between the structure and/or position of the components, and are not related to the actual size of each component.

1 and 2 , the stretchable object with play-of-color effect of the present invention comprises a base 2 and an appearance piece 3 .

The substrate 2 can be a wearable device, different types of electronic products or other daily necessities.

The appearance element 3 has a play-of-color effect, is coated or embedded on the surface of the substrate 2 to achieve an aesthetic effect, and includes a stretchable body 31 obtained by cross-linking and curing a reactive substance, and a plurality of particles 32 dispersed in the stretchable body 31.

The stretchable body 31 is obtained by polymerization of a reactive substance, which is at least one of a reactive monomer and a reactive oligomer. Depending on the material selection of the reactive substance, the stretchable body 31 obtained by polymerization may be elastic or flexible and have good processability, so it is suitable for being set on a substrate 2 with different structural patterns.

In some embodiments, the stretchable body 31 is flexible, and its constituent material is selected from polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA) or polyimide (PI), or selected from a polymer obtained by polymerizing acrylamide (AA) and methylenebisacrylamide (BIS). The reactive substance used for polymerizing to form the stretchable body 31 has a viscosity of no more than 200 cps, and is selected from acrylamide or methylenebisacrylamide, or selected from at least one of a reactive monomer and a reactive oligomer that can polymerize to obtain ethylene glycol diacrylate, polyethylene glycol dimethacrylate, or polyimide.

In some embodiments, the stretchable body 31 is elastic and its constituent material is selected from urethane acrylate (Urethane Acrylate), polyurethane (PU), liquid silicone (LSR), aliphatic urethane acrylate (AUD) or epoxy acrylate (EA). The viscosity of the reactive substance used for polymerizing to form the stretchable body 31 is between 350cps and 10000cps, and is selected from at least one of a reactive monomer and a reactive oligomer that can be polymerized to obtain aliphatic urethane acrylate, epoxy acrylate, polyurethane or liquid silicone.

The particles 32 are selected from inorganic nanoparticles, such as silicon dioxide or zirconium dioxide particles, or polymer particles, such as polystyrene (PS) or polymethyl methacrylate (PMMA), with an average particle size between 120 nm and 250 nm, a particle size distribution coefficient (CV) of less than 5%, and good monodisperse. The surfaces of the particles 32 are modified to have hydrophobic or hydrophilic functional groups, and the particles 32 are uniformly dispersed in the stretchable body 31.

Preferably, the average spherical center distance between the particles 32 is between 380nm and 780nm. Therefore, when visible light with a wavelength between 380nm and 780nm passes through the appearance element 3, it will be reflected and diffracted based on the particles 32, showing different color changes with different viewing angles, presenting a play-of-color effect.

In the present embodiment, the microparticles 32 are silica particles with a particle size between 180 nm and 240 nm, and a particle size polydispersity index (PDI) between 0.02 and 0.05. The stretchable body 31 is obtained by cross-linking and curing oligomers of aliphatic urethane diacrylate, so the appearance component 3 has good elasticity.

It should be noted that in other embodiments, the stretchable object may not be provided with the base 2 but only have the appearance piece 3, and the appearance piece 3 may be processed in different ways such as molding or cutting according to different product designs to present a specific shape.

The following describes a method for manufacturing the aforementioned appearance component 3, which includes step (a), step (b), step (c), step (d), and step (e).

The step (a) provides a first solution containing a solvent and the particles 32. The particles 32 have hydrophilic functional groups or hydrophobic functional groups on their surfaces. Depending on the surface properties of the particles 32 (e.g., zeta potential or the amount of charge on the surface, etc.), the particles 32 are dispersed in the solvent in a mutually repelling manner due to the charge repulsion generated by their own charges and/or the steric effects generated by surface modification, and do not tend to agglomerate.

The solvent is selected from anhydrous ethanol, and the microparticles 32 are obtained by surface modification of the surfaces of the primary particles with an average particle size between 120 nm and 250 nm by a surface modifier containing a hydrophilic functional group or a hydrophobic functional group, and the surface grafting rate is between 5% and 15%, and the particle size of the microparticles 32 is approximately equal to the particle size of the primary particles. The primary particles can be commercially available, or can be synthesized to obtain polymer microparticles or inorganic nanoparticles. The inorganic nanoparticles can be prepared by a sol-gel method, and the polymer microparticles can be prepared by a surfactant-free emulsion polymerization method.

In this embodiment, the initial particles are silica particles prepared by a sol-gel method, and the sol-gel method is advantageous for controlling the size and particle size distribution of the initial particles prepared, and a silane coupling agent containing a hydrophobic functional group is selected as the surface modifier to perform surface modification on the initial particles.

Specifically, in step (a), an initial solution is prepared in advance with anhydrous ethanol, deionized water, and tetraethoxysilane (TEOS) in a weight ratio of 40:8:3, and the initial solution is allowed to stand at a temperature of 25° C. to pre-hydrolyze tetraethoxysilane; ammonia water with a concentration of 30% is added to the pre-hydrolyzed initial solution, and the weight ratio of the ammonia water to the tetraethoxysilane is 1:3, so that the silicon dioxide particles (i.e., the initial particles) can be prepared by a sol-gel method. Then, the silane coupling agent (selected from γ-methacryloyloxybutyltrimethoxysilane monomer (MPS)) is added to the solution containing the silica particles to modify the surface of the silica particles, and a hydrophobic silane functional group is formed on the surface of the silica particles to obtain the particles 32. Finally, the particles 32 are dispersed in anhydrous ethanol to obtain the first solution. The weight ratio of the silane coupling agent to the silica particles is between 10 and 50, the process temperature is 40°C, and the process time is between 1 and 7 days.

The step (b) replaces the solvent of the first solution with a reactive solution to obtain a second solution. The reactive solution contains a first reactant, and based on the charge repulsion and steric hindrance effect between each other, the particles 32 are uniformly dispersed in the first reactant, and the first reactant contains a reactive monomer.

Preferably, the boiling point of the first reactant is not greater than 120°C and the viscosity is not greater than 250cps. Preferably, the solubility parameter (SP) of the particles 32 is similar to that of the first reactant, and the difference is not greater than 0.5 (cal/cm ³ ) ^1/2 , thereby helping to improve the dispersion effect of the particles 32 in the first reactant. More preferably, the difference in the solubility parameter of the particles 32 and the first reactant is not greater than 0.2 (cal/cm ³ ) ^1/2 .

In this embodiment, the solvent is removed from the first solution by solid-liquid separation (e.g., filtration or centrifugal separation), and then the reactive solution is added and mixed with the particles 32 to obtain the second solution. The first reactant is a hydrophobic methyl methacrylate monomer (MMA) having a boiling point of 101°C. The content of the particles 32 in the second solution is approximately 50wt%.

In step (c), a second reactant having a boiling point higher than that of the first reactant is added to the second solution to obtain a third solution, so that the content of the particles 32 in the third solution is between 20wt% and 25wt%; thereafter, the first reactant is evaporated from the third solution by drying or reducing pressure concentration by utilizing the difference in boiling points between the first reactant and the second reactant, and the second reactant remains in the solution to obtain a fourth solution exhibiting a play-of-color effect, wherein the content of the particles 32 in the fourth solution is between 35wt% and 50wt%, and the average spherical center distance between the particles is between 380nm and 780nm. The second reactant is the reactive substance constituting the stretchable body 31, and contains at least one of a reactive monomer and a reactive oligomer.

Preferably, the boiling point of the second reactant is at least 80° C. higher than the boiling point of the first reactant. Preferably, the boiling point of the second reactant is greater than 200° C.

In the present embodiment, in the step (c), the second reactant is an oligomer that can be polymerized to obtain aliphatic urethane diacrylate (AUD) having a boiling point of 220°C, the concentration of the particles 32 in the third solution is about 25wt%, and the first reactant (methyl methacrylate monomer) is volatilized from the third solution at a temperature of 120°C by a reduced pressure concentration method or a vacuum drying method, so that the fourth solution contains the second reactant and the particles 32 stably dispersed in the second reactant, and the content of the particles 32 in the fourth solution is 50wt%.

Specifically, in the second solution, the particles 32 are dispersed among the first reactant based on charge repulsion and steric hindrance. The preparation method of this embodiment utilizes the difference in boiling points between the first reactant and the second reactant to replace the first reactant in the solution with the second reactant by reduced pressure concentration or vacuum drying. The particles 32 can still be dispersed in the second reactant, so the second reactant has more flexibility in material selection.

In some embodiments, the solubility parameter of the second reactant is similar to that of the particles 32, with a difference of no more than 0.5 (cal/cm ³ ) ^1/2 , a viscosity of no more than 200 cps, and the second reactant is selected from at least one of a reactive monomer and a reactive oligomer that can be polymerized to obtain polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, or polyimide (PI), or can be selected from acrylamide or methylene diacrylamide. More preferably, the difference of the solubility parameter between the particles 32 and the second reactant is no more than 0.2 (cal/cm ³ ) ^1/2 .

In other embodiments, the second reactant has a viscosity of 350 cps to 10,000 cps and is selected from at least one of a reactive monomer and a reactive oligomer that can be polymerized to obtain polyurethane acrylate, polyurethane, liquid silicone or epoxy acrylate.

The step (d) adds an initiator to the fourth solution and allows the second reactant and the particles 32 to self-assemble to obtain a crystallized solution. The initiator is selected from a photoinitiator, a thermal initiator or a crosslinking agent.

The crystallization solution has a photonic crystal structure formed by the second reactant through self-assembly crystal arrangement, and presents a play-of-color effect. In the process of the second reactant self-assembly crystal arrangement, the brightness (intensity) of the solution gradually increases, and tends to be stable after the photonic crystal structure is formed. Therefore, in addition to observing whether the pattern presented in the solution changes, it is also possible to determine whether the process of self-assembly crystal arrangement is completed by observing the rising trend of the brightness of the solution during the process. In addition, compared to the existing process that takes several weeks to several months for the silicon dioxide particles to naturally settle and the crystals to stack and arrange, the embodiment of the present case takes advantage of the fact that the second reactant and the particles 32 are dispersed with each other and do not tend to agglomerate, which facilitates the particles 32 to rearrange between the second reactant, so that the self-assembly crystal arrangement process of step (d) only takes a few minutes to a few days, thereby greatly reducing the process time cost.

In some embodiments, after the initiator is added to the fourth solution in step (d), the fourth solution may be injected into a mold and/or the fourth solution may be disturbed to form a specific pattern.

In some embodiments, the step (d) further includes adding at least one of a surfactant and a dye to the fourth solution. The content of the surfactant in the fourth solution is not more than 6 wt % to improve the dispersibility of the particles 32 in the fourth solution, and is selected from cationic surfactants, anionic surfactants, or amphoteric surfactants. The content of the dye in the fourth solution is not more than 0.05 wt % to make the stretchable object a specific color, and is selected from organic dyes or inorganic dyes.

In other embodiments, the step (d) is configured with a plurality of fourth solutions, and dyes of different colors are added to the fourth solutions respectively. Afterwards, the fourth solutions can be injected into the same mold, and the fourth solutions can present specific texture patterns by controlling the injection position and injection sequence of the fourth solutions or by external force interference such as disturbance.

The step (e) causes the second reactant of the crystallization solution to crosslink and solidify, so as to obtain the stretchable object with play-of-color effect (i.e., the appearance member 3 shown in FIG. 1 ). Depending on the type of the initiator added in the step (d), a corresponding process will be used in the step (e) to cause the crystallization solution to crosslink and solidify.

In this embodiment, the step (d) is to add a photoinitiator to the fourth solution, and the step (e) is to cross-link and solidify the second reactant by ultraviolet light irradiation to form the stretchable body 31, and the second reactant is a reactive monomer and/or oligomer of an elastic body, so the stretchable body 31 has elasticity.

Preferably, the energy density of the ultraviolet light is between 400 and 650 mW/cm ² and the wavelength is 365 nm, so that the crystallization solution can receive sufficient energy within a few minutes, so that the second reactant is polymerized within 2-3 minutes to complete the crosslinking and curing, so that the stretchable body 31 has good stretchability. More preferably, the crosslinking and curing reaction of step (e) is completed within 1 minute.

In some embodiments, the second reactant is composed of at least one of a reactive monomer and a reactive oligomer, so that the stretchable body 31 is flexible, and its tensile strength (TS) is between 5MPa and 15MPa, and its elongation (EL) is between 130% and 200%.

In other embodiments, the initiator is a thermal initiator, and the step (e) is to heat-treat the crystallization solution by irradiating with infrared light or using a temperature-controlled tank to place the crystallization solution in an environment with a temperature between 40°C and 70°C, so that the second reactant undergoes cross-linking and solidification to form the stretchable body 31.

In summary, the method for preparing the stretchable object with play-of-color effect of the present invention is to first prepare a second solution composed of the first reactant and the particles 32, and use the boiling point difference between the first reactant and the second reactant to replace the first reactant with the second reactant, so that the particles 32 can still be dispersed in the second reactant and do not tend to agglomerate, which is conducive to the self-assembly of crystal arrangement, thereby greatly reducing the process time, and is more flexible in the material selection of the second reactant, which is conducive to the preparation of the appearance piece 3 with stretchability and play-of-color effect, and has both aesthetic effect and good processability, so it can indeed achieve the purpose of the present invention.

However, the above is only an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the present patent.

2: Base 3: Appearance 31: Stretchable body 32: Particles

Other features and effects of the present invention will be clearly presented in the implementation method with reference to the drawings, in which: Figure 1 is a schematic diagram illustrating an embodiment of the stretchable object with colorful effect of the present invention; and Figure 2 is a schematic diagram to assist in explaining the enlarged view of A in Figure 1 to illustrate the structure of the particles.

2: Base

3: Appearance parts

Claims (10)

A method for preparing a stretchable object with a play-of-color effect, comprising: Step (a), providing a first solution containing a solvent and a plurality of dispersed particles with modified surfaces; Step (b), replacing the solvent of the first solution with a reactive solution to obtain a second solution, wherein the reactive solution contains a first reactant, the particles are uniformly dispersed in the first reactant, and the first reactant contains a reactive monomer; Step (c), adding a second reactant having a boiling point higher than that of the first reactant to the second solution to obtain a third solution, and allowing the first reactant to volatilize from the third solution to obtain a fourth solution, wherein the second reactant contains at least one of a reactive monomer and a reactive oligomer; Step (d), adding an initiator to the fourth solution and standing it, so that the second reactant and the particles are self-assembled to obtain a crystallized solution; and Step (e), cross-linking and solidifying the second reactant of the crystallized solution to obtain a stretchable object with a play-of-color effect. A method for making a stretchable object with a play-of-color effect as described in claim 1, wherein the boiling point of the second reactant is at least 80°C higher than the boiling point of the first reactant. A method for preparing a stretchable article with play-of-color effects as described in claim 1, wherein the second reactant has a viscosity of no more than 200 cps and is selected from acrylamide, methylene diacrylamide, or at least one of reactive monomers and reactive oligomers that can be polymerized to obtain polyethylene glycol diacrylate, polyethylene glycol dimethacrylate or polyimide; or, the second reactant has a viscosity of between 350 cps and 10,000 cps and is selected from at least one of reactive monomers and reactive oligomers that can be polymerized to obtain polyurethane, liquid silicone, aliphatic polyurethane acrylate or epoxy acrylate. The method for making a stretchable article with play-of-color effect as described in claim 1, wherein the step (d) is to add a photoinitiator to the fourth solution, and the step (e) is to crosslink and cure the second reactant by ultraviolet light irradiation, and the energy density of the ultraviolet light is between 400 and 650 mW/ ^cm2 . A method for preparing a stretchable object with a play-of-color effect as described in claim 1, wherein, in the step (a), a surface modifier is used to modify the surface of a majority of initial particles having an average particle size between 120 nm and 250 nm to obtain a surface grafting rate of the particles between 5% and 15%, and the particle size distribution coefficient (CV) of the initial particles is less than 5%. A method for preparing a stretchable object with play-of-color effects as described in claim 1, wherein in the step (c), the first reactant is volatilized from the third solution by drying or reducing pressure concentration, the content of the particles in the third solution is between 20wt% and 25wt%, the content of the particles in the fourth solution is between 35wt% and 50wt%, and the average spherical center distance between the particles in the fourth solution is between 380nm and 780nm. A method for producing a stretchable object with play-of-color effect as described in claim 1, wherein the step (d) further adds at least one of a surfactant and a dye to the fourth solution. A stretchable object with play-of-color effects, comprising: a substrate; and an appearance piece, made by the manufacturing method described in any one of claims 1 to 7, stretchable and having play-of-color effects, coated or embedded on the surface of the substrate, including a stretchable body obtained by cross-linking and curing a reactive substance, and a plurality of microparticles dispersed in the stretchable body, and the reactive substance is selected from at least one of a reactive monomer and a reactive oligomer. A stretchable object with play-of-color effects as described in claim 8, wherein the surfaces of the particles are modified to have hydrophobic or hydrophilic functional groups, the average particle size is between 120nm and 250nm, the distribution coefficient (CV) is less than 5%, and the average spherical center distance between each other is between 380nm and 780nm. A stretchable object with a play-of-color effect, made by the method described in any one of claims 1 to 7, comprising: a stretchable body, which is obtained by cross-linking and solidifying a reactive substance and has stretchability; and a plurality of particles, which are dispersed in the stretchable body.

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