Environmentally friendly photocuring method for elastic sheets

Abstract

This invention provides an environmentally friendly photocuring method for producing elastic sheets. First, an elastic material is pressed into a sheet shape, the elastic material containing a photoinitiator. Then, a thin sheet is placed on one side of the sheet-shaped elastic material, and pressure is applied to bond the two together to form a semi-finished elastic sheet. Next, light is irradiated onto the surface of the elastic material in the semi-finished elastic sheet, causing the photoinitiator within the elastic material to absorb the light and undergo a polymerization reaction, promoting appropriate curing of the surface of the elastic material. Finally, the semi-finished elastic sheet is rolled up and placed in a greenhouse, where sunlight or light from within the greenhouse cures the semi-finished elastic sheet into an elastic sheet.

Description

[Technical Field]

[0001] This invention relates to the field of rubber sheet technology, and more specifically to an environmentally friendly photocuring method for producing elastic sheets. [Previous Technology]

[0002] Note that rubber materials need to undergo a vulcanization process to be shaped and matured into products. The method generally involves adding a vulcanizing agent (such as sulfur) to the rubber material and heating the rubber material at high temperature in a vulcanizing oven (referred to as an oven) (taking a tunnel oven as an example, the vulcanization temperature is about 150°C to 200°C) and / or pressurizing it, so that the vulcanizing agent and the rubber molecular chain can undergo a cross-linking reaction to form a cross-linked structure, thereby obtaining the required mechanical properties and chemical stability and improving the performance of the rubber product. In addition, the vulcanization reaction will accelerate with the increase of temperature, and the increase of pressure will also accelerate the vulcanization speed of rubber. The vulcanization time, temperature and pressure are adjusted according to the rubber material formulation and product requirements.

[0003] It is known that ovens used for the vulcanization process of rubber materials are not only energy-consuming (for example, a tunnel oven with a power of 2300Kw consumes about 2300Kw of energy per hour of operation), but also a source of pollution (for example, a tunnel oven with a power of 2300Kw emits about 1100kg of CO2 per hour of operation, as well as pollutants such as high-temperature solvent volatilization). Under the current needs and goals of environmental protection and carbon emission control, there is a lot of room for improvement.

[0004] In addition, conventional sports mats or step mats, which are made of rubber as the main material, are usually made of at least two sheets bonded together (e.g., a sports mat is made of an elastic layer bonded to a fabric, and a step mat is made of an elastic layer bonded to a non-slip layer). The bonding method is to use adhesive or adhesive-free bonding technology (using the gas pressure generated when the foaming agent in the rubber material foams to bond the two sheets together). After the two sheets are vulcanized and cured at high temperature, the elastic material often shrinks, causing the bonding to deform.

[0005] Secondly, the high-temperature vulcanization and curing process can easily cause the chemical agents in rubber materials to become unstable, degrade, leach out, or even interact to produce harmful components, thus affecting product quality. Furthermore, because high-temperature vulcanization increases the instability of the chemical agents in rubber materials, the proportion of chemical agents added must be precise. Even slight errors can lead to poor product quality and reduced yield. In other words, the tolerance for errors in chemical agent addition is very low, increasing the difficulty of manufacturing rubber products, but there are also areas for improvement and progress. [Summary of the Invention]

[0006] The main objective of this invention is to provide an environmentally friendly photocuring method for elastic sheets, which avoids the problems of deformation when elastic materials and sheets are bonded together, as well as the problems of unstable, lost, deteriorated, or released chemical agents, or even the generation of harmful components. It can improve the tolerance of error values ​​when adding chemical agents, greatly improve the product yield, and the overall energy consumption is far lower than that of conventional ovens used to cure rubber, which can reduce production costs. Furthermore, there is no pollution such as high-temperature solvent evaporation from ovens, which is very environmentally friendly. The resulting elastic sheets have higher softness, are easy to process, and have great practical value.

[0007] Therefore, in order to achieve the aforementioned objective, the present invention provides an environmentally friendly photocuring method for producing an elastic sheet, the steps of which include at least: pressing: pressing an elastic material into a sheet shape; bonding: bonding a thin sheet to one side of the sheet-shaped elastic material and applying pressure to bond the two together to form an elastic sheet semi-finished product; photocuring: irradiating the surface of the elastic material of the elastic sheet semi-finished product with a light source, causing the elastic material to absorb the light and heat and thus properly cure the surface; photocuring: rolling up the elastic sheet semi-finished product and placing it in a greenhouse, using sunlight irradiated in the greenhouse or light source inside the greenhouse to cure the elastic sheet semi-finished product into an elastic sheet.

[0008] Preferably, in the tableting step, the elastic material is one of an elastomer, an elastomer mainly composed of plant-based elastic materials, or an all-plant elastomer.

[0009] Preferably, in the bonding step, the sheet is either a fabric or an elastic sheet.

[0010] Preferably, the elastic material further includes a heat-absorbing material, which allows the elastic material to absorb the heat generated by sunlight and light irradiation in a greenhouse, and supply the vulcanizing agent in the elastic material to react, so that the elastic sheet semi-finished product is vulcanized and matured into an elastic sheet at room temperature.

[0011] Preferably, the elastic material further includes a moisture-reactive material, which enables the elastic material to absorb moisture in the greenhouse and promote the proper hardening of the elastic sheet semi-finished product to cooperate with vulcanization and curing into an elastic sheet.

[0012] Preferably, in the photo-pre-curing step, the light source is one of ultraviolet light, X-ray, laser light or microwave, and the elastic material further contains a photoinitiator, so that when the surface of the elastic material is irradiated by light, the photoinitiator in the elastic material can absorb the light and generate a polymerization reaction, thereby promoting the proper curing of the surface of the elastic material.

[0013] Preferably, the step of photo-pre-curing and photo-vulcanization includes a barrier means, which is to attach a peelable barrier sheet to the surface of the elastic material to prevent the surface of the elastic material from sticking together when the elastic sheet semi-finished product is rolled up.

[0014] Preferably, the barrier sheet is provided with a heat-conducting material to conduct heat generated by sunlight and light in the greenhouse to the elastic material.

[0015] Preferably, the surface of the barrier sheet is provided with a number of textures, which can promote the formation of textures on the surface of the elastic sheet after vulcanization and curing.

[0016] Preferably, during the photo-curing step, the greenhouse is equipped with several lamps that can emit light, and the power required for the operation of the lamps is supplied by power generated by several solar panels installed outside the greenhouse. [Simplified Explanation of the Diagram]

[0033] The first figure is a flowchart of a preferred embodiment of the present invention.

[0034] The second figure is a flowchart of another preferred embodiment of the present invention.

Implementation Method

[0017] Hereinafter, two preferred embodiments of the present invention will be described in further detail with reference to the accompanying drawings:

[0018] First, please refer to the first figure. The environmentally friendly photocuring method 100 for the elastic sheet of the present invention is to produce the elastic sheet by a non-high temperature curing method. The first step is pressing 110: an elastic material is pressed into a sheet-like elastic body using conventional rolling mill or flat press and other equipment. The elastic material may include natural rubber, synthetic rubber, plastic and / or recycled rubber or plastic, which are commonly used to make elastic mats (such as floor mats, anti-slip mats or sports mats), and is mixed with vulcanizing agents (the present invention uses room temperature vulcanizing agents), accelerators, antioxidants and other additives, as well as phototriggers or light-curing resins. The elastic material may also be an elastomer mainly composed of plant-based elastic materials (i.e., the proportion of plant-based elastic materials used is higher than that of other elastic materials). Such plant-based elastic materials are, for example, natural rubber (which is the sap obtained from rubber trees, and therefore belongs to plant-based elastic materials), but are not limited thereto. The elastic material may also be a completely plant-based elastomer, that is, containing only natural rubber and not other elastic materials. The types of elastic materials added to the aforementioned elastic material are determined according to the product characteristics requirements of the finished elastic pad. This is common technology and will not be elaborated here. As for vulcanizing agents and other additives, they are common additives for controlling the vulcanization and maturation of rubber. They are also common technology and will not be elaborated here on the detailed composition and vulcanization and maturation principles of various additives.

[0019] The second step of the present invention is bonding 120: a thin sheet is bonded to one side of a sheet-like elastic material, and pressure is applied using conventional rolling mills or flat presses to bond the thin sheet and the sheet-like elastic material together to form a semi-finished elastic sheet. The thin sheet can be fabric or elastic sheet material.

[0020] The third step of the present invention is photocuring 130: A light source is used to irradiate the surface of the elastic material of the elastic sheet semi-finished product, causing the photoinitiator within the elastic material to absorb the light and undergo a polymerization reaction, thereby promoting the appropriate curing and maturation of the surface of the elastic material. The light source can be ultraviolet (UV), laser, X-ray, or microwave, but is not limited to any particular type. In this embodiment, ultraviolet light is used. The irradiation time is approximately 1 to 5 minutes when the ultraviolet light is a common UV lamp with an intensity of approximately 1000 mW / cm²; approximately 2 to 6 minutes when the ultraviolet light is a UV-LED lamp with a wavelength of 365 nm and an intensity of approximately 500-1000 mW / cm²; and approximately 1 to 3 minutes when the ultraviolet light is a mercury lamp with a wavelength of 200-400 nm and an intensity of approximately 1000 mW / cm² or higher. The polymerization reaction that occurs when the photoinitiator absorbs ultraviolet light is a known technique and will not be described in detail here. The present invention mainly utilizes such techniques to properly cure and mature the surface of the elastic material.

[0021] The final step of the present invention is photocuring 140: the elastic sheet semi-finished product is rolled up and placed in a greenhouse, and the elastic sheet semi-finished product is continuously irradiated day and night for several days by sunlight entering the greenhouse and light generated inside the greenhouse, so that the elastic sheet semi-finished product is cured into an elastic sheet. The method of rolling up the elastic sheet semi-finished product is to place the sheet-like elastic material inside the roll, but it is not limited. The greenhouse is a conventional fully transparent agricultural cultivation room for growing vegetables and fruits, which allows sunlight to enter the interior during the day. Furthermore, a plurality of solar panels are installed on the outside of the greenhouse (such as the roof and other light-receiving surfaces), and a plurality of lamps are installed inside the greenhouse. Each lamp can emit ultraviolet light. The power required for its operation is supplied by the power generated by the solar panels installed outside the greenhouse, or by a number of batteries that store the power generated by the solar panels, so that when there is no sunlight at night, the lamps inside the greenhouse can emit ultraviolet light. Based on this, the semi-finished elastic sheet material in the greenhouse can be exposed to sunlight and the temperature inside the greenhouse during the day (room temperature 25 degrees Celsius, and the room temperature inside the greenhouse reaches about 60°C to 70°C in hot climates), and at night it can be exposed to ultraviolet light from various lamps. Through the continuous exposure to light and temperature inside the greenhouse day and night, the elastic material is not only continuously vulcanized at room temperature by the vulcanizing agent, but also slightly hardened by the polymerization reaction generated by the photoinitiator absorbing light. Thus, the semi-finished elastic sheet material is cured into an elastic sheet in a few days (as fast as 3 to 5 days, as slow as 2 to 3 weeks). After confirming that the elastic sheet is fully cured, the elastic sheet can be taken out of the greenhouse for subsequent processing such as cutting to make elastic sheet products with non-rigid physical properties.

[0022] The amount of vulcanizing agent used in the aforementioned elastic material depends on the required degree of vulcanization and curing of the finished elastic sheet and the vulcanization time required for the photocuring step 140. This can be varied and adjusted according to product requirements. The amount of photoinitiator used and the light irradiation time depend on the required degree of hardening and curing of the surface of the elastic material in the photocuring step 130 (so that the semi-finished elastic sheet can be rolled up and the surfaces of the elastic material do not stick to each other during rolling up), and the degree of hardening required for the curing of the elastic material in the photocuring step 140. This can also be varied and adjusted according to product requirements.

[0023] In addition, the time it takes for the semi-finished elastic sheet to mature into an elastic sheet in a greenhouse is affected by the amount of vulcanizing agent and photoinitiator used, as well as by the thickness of the elastic material and the type of elastic material selected. These are parameters that can be adjusted according to product requirements.

[0024] Accordingly, the environmentally friendly photocuring method 100 of the present invention, through the steps of pressing 110, bonding 120, photocuring 130 and photocuring 140, places the semi-finished elastic sheet in a greenhouse for photocuring and curing. It can prepare an elastic sheet made of the sheet and elastic material bonded together at room temperature of 25°C to 70°C. This is different from the conventional industrial rapid manufacturing thinking of using ovens (such as tunnel ovens) for high-temperature (150°C to 200°C) vulcanization and curing of rubber products. Not only will the shrinkage of the elastic material after high-temperature curing affect the quality of the bonded sheet, but the chemical additives such as vulcanizing agents and photoinitiators in the elastic material have high stability. It will not have the problems of unstable chemical agents, loss, deterioration or release during the high-temperature curing of traditional rubber products (for example, zinc stearate produced by the chemical reaction of zinc oxide powder and stearic acid is easy to be released from the rubber surface, and zinc oxide powder and stearic acid are used for the vulcanization of rubber), or even the interaction to produce new harmful components.

[0025] Secondly, conventional ovens for curing rubber products are not only energy-intensive but also sources of pollution (solvent evaporation, CO2 emissions, etc.). In this invention, energy consumption and CO2 emissions only occur in the light pre-curing step 130 (where light irradiates the surface of the elastic material of the semi-finished elastic pad). The light vulcanization step 140 involves placing the semi-finished elastic pad in a greenhouse for light vulcanization and curing, thus eliminating energy consumption and CO2 emissions. Overall, the energy consumption is far lower than that of an oven (for example, a 2300kW tunnel oven consumes approximately 2300kW per hour of operation). The energy consumption of a 0.5kW UV lamp with a 1 square meter size irradiating ultraviolet light for 1 hour is only about 0.5kW, a significant difference. The CO2 emissions are also much lower than those of an oven (for example, a tunnel oven with a power of 2300kW emits about 1100kg of CO2 in 1 hour of operation, while a 0.5kW UV lamp with a 1 square meter size irradiating ultraviolet light for 1 hour emits only about 0.25kg of CO2, a significant difference). This can reduce production costs. Furthermore, this invention does not have the pollution caused by the high-temperature solvent evaporation of an oven, which is in line with the requirements of environmental protection and carbon emission control.

[0026] Furthermore, the elastic sheet produced by this invention is cured in a greenhouse, and its room-temperature vulcanization crosslinking degree differs from that of high-temperature curing in an oven. This results in higher softness, making it not only easier to process but also suitable for manufacturing leather and other products. Moreover, the chemical agents in this elastic material do not react excessively in non-high-temperature processes, exhibiting higher stability and improving the tolerance for errors when adding chemical agents (even if the amount of added chemical agents slightly exceeds the predetermined value, it will not affect the quality and expected physical properties of the elastic sheet), thus significantly improving the product yield of the elastic sheet. Furthermore, the greenhouse curing method of this invention prevents the composition of the elastic sheet from being damaged by high temperatures, making it easy to recycle and reuse.

[0027] Since the photocuring 140 step of the present invention is to cure the elastic sheet in a greenhouse, in order to increase the curing and curing speed of the elastic sheet, a heat-absorbing material can be added to the elastic material, such as a soot-based heat-absorbing material (such as graphite, iron black, iron blue, iron red, chrome green, carbon black, bituminous coal), etc., but not limited thereto, so that the elastic material can better absorb the heat generated by sunlight and light irradiation in the greenhouse, and supply the elastic material to carry out the curing reaction, so that the semi-finished elastic sheet can be cured at room temperature into an elastic sheet.

[0028] Alternatively, a moisture-reactive material, such as moisture-reactive single-liquid polyurethane (PU), may be added to the elastic material to enable it to absorb moisture in the greenhouse, promote proper hardening of the elastic sheet semi-finished product to cooperate with vulcanization and curing into an elastic sheet, and also increase the curing speed of the elastic sheet.

[0029] Furthermore, as shown in Figure 2, this is another preferred embodiment of the environmentally friendly photocuring method 200 for elastic sheets of the present invention. The steps are generally the same as those of the environmentally friendly photocuring method 100, except that a barrier means 210 is included between the photocuring pre-curing 130 and photocuring 140 steps. A peelable barrier sheet (not shown in the figure) is attached to the surface of the elastic material. This barrier sheet can be a conventional release film, but is not limited to it. Based on this, the barrier sheet can prevent the surface of the elastic material from sticking together when the semi-finished elastic sheet is rolled up, thereby reducing the energy consumption of the photocuring pre-curing 130 step in curing and maturing the surface of the elastic material (the energy of the light can be reduced, and the irradiation time can be shortened). Also, the surface of the barrier sheet can be textured, so that the surface of the elastic sheet forms texture after curing. Furthermore, a heat-conducting material can be added to the barrier sheet so that when the semi-finished elastic sheet is rolled up and placed in a greenhouse, the heat-conducting material in the barrier sheet can conduct the heat generated by sunlight and light in the greenhouse to the elastic material, promoting the vulcanization and curing of the elastic material.

[0030] In summary, the environmentally friendly photocuring method for elastic sheets provided by the present invention, through a series of steps including sheeting, lamination, photocuring, and photocuring, not only avoids the problem of shrinkage of the elastic material after high-temperature curing affecting the quality of the sheet lamination deformation, but also avoids the problems of unstable, wasted, deteriorated, or released chemical agents or even the generation of harmful components during the high-temperature curing of conventional rubber products. The chemical agents have higher stability, which can improve the tolerance of error values ​​when adding chemical agents and greatly improve the product yield of the elastic sheet. In addition, the overall energy consumption of the present invention is far lower than that of conventional ovens used to cure rubber, which can reduce production costs. There is no pollution such as high-temperature solvent evaporation from ovens, which is very environmentally friendly. The elastic sheet produced by the present invention has higher softness, is easy to process, and its overall composition is not damaged by high temperature and is easy to recycle and reuse. Not only is the process unprecedented, but it also has many other functional improvements. Therefore, the present invention does meet the requirements of an invention patent, and an application is filed in accordance with the law.

[0031] The above description is only a few preferred embodiments of the present invention and is not intended to limit the present invention. Anyone with ordinary knowledge in the art can make some modifications, alterations and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An environmentally friendly photocuring method for producing an elastic sheet, the steps of which include at least: Compressed sheets: compressing an elastic material into a sheet shape, the elastic material containing a vulcanizing agent; Bonding: A thin sheet is placed on one side of a sheet of elastic material and pressure is applied to bond the two together to form a semi-finished elastic sheet. Pre-curing by light: A light source is used to irradiate the surface of the elastic material of the semi-finished elastic sheet for a predetermined time, causing the elastic material to absorb the light and heat, thus properly curing the surface and producing an anti-stick effect. Photocuring: After the semi-finished elastic sheet is rolled up, it is placed in a greenhouse. The semi-finished elastic sheet is continuously exposed to sunlight and light generated inside the greenhouse for several days, day and night, so that the semi-finished elastic sheet is vulcanized and cured into an elastic sheet.

2. The environmentally friendly photocuring method for the elastic sheet material as described in claim 1, wherein, In the tableting process, the elastic material is one of the following: an elastomer, an elastomer mainly composed of plant-based elastic materials, or an all-plant elastomer.

3. The environmentally friendly photocuring method for the elastic sheet material as described in claim 1, wherein, In the bonding process, the sheet is either a fabric or an elastic sheet.

4. The environmentally friendly photocuring method for the elastic sheet material as described in claim 1, wherein, The elastic material further includes a heat-absorbing material, which allows the elastic material to absorb the heat generated by sunlight and light irradiation in a greenhouse, supplying the vulcanizing agent in the elastic material to react, so that the semi-finished elastic sheet can be vulcanized and matured at room temperature into an elastic sheet.

5. An environmentally friendly photocuring method for manufacturing the elastic sheet as described in claim 1, wherein, The elastic material further includes a moisture-reactive material, which allows the elastic material to absorb moisture in the greenhouse, promoting the proper hardening of the elastic sheet semi-finished product to facilitate vulcanization and curing into an elastic sheet.

6. An environmentally friendly photocuring method for the elastic sheet material as described in claim 1, wherein, In the photo-pre-curing step, the light source is one of ultraviolet light, X-ray, laser light or microwave. The elastic material also contains a photoinitiator, so that when the surface of the elastic material is irradiated by light, the photoinitiator in the elastic material can absorb the light and generate a polymerization reaction, promoting the proper curing of the surface of the elastic material.

7. An environmentally friendly photocuring method for the elastic sheet material as described in claim 1, wherein, Between the photocuring and photocuring steps, there is a barrier method, which involves attaching a peelable barrier sheet to the surface of the elastic material to prevent the surfaces of the elastic material from sticking together when the semi-finished elastic sheet is rolled up.

8. The environmentally friendly photocuring method for the elastic sheet material as described in claim 7, wherein, The barrier sheet incorporates a heat-conducting material to conduct heat generated by sunlight and light exposure in the greenhouse to the elastic material.

9. The environmentally friendly photocuring method for the elastic sheet material as described in claim 8, wherein, The surface of the barrier sheet has several textures, which can promote the formation of textures on the surface of the elastic sheet after vulcanization and curing.

10. An environmentally friendly photocuring method for the elastic sheet as described in claim 1 or 6, wherein, In the photocuring process, the greenhouse is equipped with several lamps that can emit light. The power required for the operation of these lamps is supplied by electricity generated by several solar panels installed outside the greenhouse.

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