Continuous fiber dehumidification box for polyurethane resin and dehumidification process

Abstract

The invention relates to the field of resin processing, in particular to a continuous fiber dehumidification box for polyurethane resin and a dehumidification process. Wherein the dehumidification box comprises a box body, a glass ceramic sheet and a mirror surface aluminum plate, the two ends of the box body are open, fibers can pass through the box body, the glass ceramic sheet and the mirror surface aluminum plate are installed in the box body, and the glass ceramic sheet is coated with graphene; the inclination angle of the two ends, opposite to the glass ceramic sheet, of the mirror surface aluminum plate is alpha, and the inclination angle of the mirror surface aluminum plates located on the two sides of the glass ceramic sheet is beta; the thickness of the fibers is a mm, the density of the fibers is b bundles / cm < 3 >, and the tex value t of each bundle of fibers is 1200-9600 tex / bundle; according to the method, moisture on the yarn can be effectively removed, a sizing agent on the yarn cannot be damaged, it is guaranteed that the surface of a plate is smooth and free of bubbles, and the mechanical property and the thermodynamic property of a product are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of resin processing, and more specifically, to a continuous fiber dehumidification box and dehumidification process for polyurethane resin. Background Art

[0002] Pultrusion is a process for the continuous production of linear composite products. Using resin as the matrix material and fibers and fabrics as reinforcements, the product is formed under external forces through a process of impregnation, preforming, and hot-molding curing, ultimately resulting in a composite product of any length and cross-section. Pultrusion boasts high production efficiency, with extrusion speeds adjustable between 0.1 and 2 m / min. Its products are widely used in wind turbine blade beams, cooling tower profiles, photovoltaic frames, and other applications.

[0003] Polyurethane resins for pultruded profiles typically consist of two components: isocyanate and polyester polyol. Isocyanate reacts readily with water, initially producing unstable carbamic acid, which then quickly decomposes into amine and carbon dioxide. This can lead to bubbles on the surface of the pultruded profile, rendering the product scrapped. Therefore, when selecting polyurethane resins for pultruded profiles, a closed-mold injection process is typically used to effectively minimize the chance of isocyanate coming into contact with free water molecules in the environment. However, summer rain is frequent and workshop humidity is high, allowing free water molecules in the environment to come into contact with and adsorb onto the continuous fiber yarn. As the yarn, under the traction of the pultruder, enters the injection box, the isocyanate reacts with the adsorbed water molecules, causing large bubbles to form on the surface of the pultruded profile, directly rendering the product scrapped and significantly increasing production costs. Summary of the Invention

[0004] The present application provides a continuous fiber dehumidification box and dehumidification process for polyurethane resin. The present application can effectively remove moisture from the yarn without destroying the sizing agent on the yarn, ensuring that the surface of the board is smooth and free of bubbles, and the mechanical properties and thermodynamic properties of the product are significantly improved.

[0005] In the first aspect, the present application provides a continuous fiber dehumidification box for polyurethane resin, which adopts the following technical solution:

[0006] A continuous fiber dehumidification box for polyurethane resin, comprising a box body with openings at both ends for fiber passage, a glass-ceramic sheet and a mirrored aluminum plate installed within the box body, the glass-ceramic sheet being located on the inner side wall of the box body in the direction of fiber thickness and parallel to a surface in the direction of fiber thickness, the mirrored aluminum plate being located on the side wall of the box body opposite the glass-ceramic sheet and on the side walls of the box body on both sides of the glass-ceramic sheet, the mirrored aluminum plate and the glass-ceramic sheet enclosing a dehumidification zone with openings at both ends and being parallel to the direction of fiber travel;

[0007] The microcrystalline glass sheet is coated with graphene; both ends of the mirrored aluminum plate opposite to the microcrystalline glass sheet are tilted toward the microcrystalline glass sheet at an angle of α; the mirrored aluminum plates on both sides of the microcrystalline glass sheet are tilted away from each other at an angle of β near one end of the microcrystalline glass sheet; the fiber has a thickness of a mm and a density of b bundles / cm 3 , the tex value t of each fiber bundle is 1200-9600tex / bundle;

[0008] in, △R is the ratio of the reflectivity of the glass-ceramic sheet after attenuation to the baseline reflectivity without attenuation, and k is the proportional constant, which is 3.7*10 -8 ;

[0009] △R' is the ratio of the reflectivity of the glass-ceramic sheet after attenuation to the baseline reflectivity without attenuation, and k' is the proportional constant, which is 6.0*10 -8 .

[0010] Among them, the ratio of the reflectivity of the microcrystalline glass sheet after attenuation and the baseline reflectivity when there is no attenuation means that within this attenuation range, all parts of the fiber are heated evenly, meeting the performance requirements of subsequent products, and is an artificial setting.

[0011] Furthermore, the inclination angle α is 5-30°, preferably 7-29.5°, and preferably, the inclination angle β is 10-50°, preferably 12-48°.

[0012] Furthermore, the ranges of ΔR and ΔR' are: 0.9≤ΔR<1, 0.9≤ΔR'<1.

[0013] Furthermore, the graphene on the glass-ceramic sheet has a thickness of 10-200 μm and a roughness Ra of 1-50 μm.

[0014] Furthermore, asbestos mesh is provided between the microcrystalline glass sheet and the box body, and between the mirror aluminum plate and the box body.

[0015] In a second aspect, the present application provides a dehumidification process, which adopts the following technical solution:

[0016] A dehumidification process for a continuous fiber dehumidification box for polyurethane resin comprises the following steps: allowing the fibers drawn out by a yarn guide plate to pass through the dehumidification box.

[0017] Furthermore, the temperature of the dehumidification box is 80°C to 200°C.

[0018] Furthermore, the fiber drawing speed is 0.4-2 m / min, and the drying distance is 1-500 mm.

[0019] In summary, this application has the following beneficial effects:

[0020] 1. In this application, graphene is coated on a microcrystalline glass sheet. Since the graphene coated on the surface is composed of a single layer of carbon atoms tightly arranged to form a two-dimensional hexagonal lattice structure, the interaction between carbon atoms makes graphene have excellent electrical conductivity. When an external current passes through the graphene, the electrons between the carbon atoms will be quickly transferred in the structure, generating friction and collision, thereby generating heat. In addition, graphene has an extremely high thermal conductivity, which enables graphene to quickly and evenly transfer heat during the heating process, avoiding local overheating or excessive temperature difference in the heating area, and ensuring that there is The water molecules adsorbed on the continuous fiber yarn in the heating area are effectively volatilized, and the sizing agent on the surface of the continuous fiber will not be destroyed due to local overheating. Therefore, the water molecules adsorbed on the yarn are completely volatilized during the continuous production process of polyurethane pultrusion products, ensuring that the surface of the board is smooth and free of bubbles. At the same time, since the sizing agent is not destroyed, the interfacial bonding ability between the resin matrix and the reinforcing fiber is enhanced, and the mechanical properties and thermodynamic properties of the product are significantly improved. The moisture content of the yarn remains at a stable level below 0.2% throughout the year, the bubble occurrence rate of the pultruded profile is less than 2% / meter, and the product qualification rate reaches more than 90%.

[0021] 2. To ensure that all parts of the fiber are heated more evenly during the dehumidification process, the three mirrored aluminum plates of this application are set at a specified inclination angle. The mirrored aluminum plate opposite the microcrystalline glass sheet is V-shaped. This arrangement ensures that when heat is consumed by operations such as dehumidification, the V-shaped mirrored aluminum plate has a certain focusing effect on the radiation without excessive concentration, further reducing the temperature difference between the upper and lower surfaces of the fiber, making the fiber heated more evenly, further reducing damage to the sizing agent, and improving subsequent product performance. At the same time, the mirrored aluminum plates on both sides of the microcrystalline glass sheet not only reduce the heat dissipation outside the box, but also assist the V-shaped mirrored aluminum plates to make the fiber heated more evenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of the dehumidification box in an embodiment of the present application.

[0023] Explanation of the accompanying reference numerals: 1. Box body; 11. Hinge; 12. Flat-mouth buckle; 2. Microcrystalline glass sheet; 3. Mirror aluminum plate; 31. First aluminum plate; 32. Second aluminum plate; 4. Asbestos mesh; 5. Fiber path area. DETAILED DESCRIPTION

[0024] The present application is further described in detail below with reference to the accompanying drawings and examples.

[0025] Example

[0026] like Figure 1As shown, this embodiment provides a continuous fiber dehumidification box for polyurethane resin, including a box body 1 with openings at both ends for fibers to pass through, a microcrystalline glass sheet 2 and a mirrored aluminum plate 3 installed in the box body 1, wherein the box body 1 of this embodiment can be: making two L-shaped stainless steel plates with a length of 200mm-1000mm, a height of 100mm-500mm, and a width of 100mm-1000mm, a long end of one steel plate and a short end of the other steel plate are fixedly connected by a stainless steel hinge 11, and the other short end and the other long end are connected by a stainless steel flat-mouth buckle 12, forming a box-type structure with open ends, so that the box body 1 can be opened at any time later, which is convenient for repairing the dehumidification box or combing the fibers. The area where the fibers pass is the fiber passage area 5.

[0027] A 5-20mm thick asbestos mesh 4 is laid on all four inner sides of the box 1. The asbestos mesh 4 is positioned between the glass-ceramic sheet 2 and the inner wall of the box 1, or between the mirrored aluminum plate 3 and the inner wall of the box 1. A single glass-ceramic sheet 2 is positioned on the inner wall of the box 1 in the direction of the fiber thickness, parallel to the plane in the fiber thickness direction. In this embodiment, it is directly above the fibers of the glass-ceramic sheet 2. The glass-ceramic sheet 2 is also coated with graphene, a single layer of carbon atoms. The graphene coating has a thickness of 10-200μm and a roughness Ra of 1-50μm.

[0028] The mirrored aluminum plate 3 is located on the side wall of the box 1 relative to the microcrystalline glass sheet 2 and on the side wall of the box 1 on both sides of the microcrystalline glass sheet 2. The mirrored aluminum plate 3 and the microcrystalline glass sheet 2 form a dehumidification area with openings at both ends and are parallel to the direction of fiber advancement; in addition, the graphene coating is connected to a power source, thereby causing the graphene to heat up and control the temperature of the dehumidification box. The power supply method can be direct contact method, edge contact method or prefabricated electrode method, etc., which is a prior art and will not be described in detail in this embodiment.

[0029] There are three mirrored aluminum plates 3. The first aluminum plates 31 are located on either side of the glass-ceramic sheet 2, that is, on the two vertical side walls of the box 1. Each vertical side wall of the box 1 has a first aluminum plate 31. The two first aluminum plates 31 are tilted away from each other, and the tilt angle of the first aluminum plates 31 is β. The vertical centers of the first aluminum plates 31 and the vertical centers of the fibers are aligned. The second aluminum plate 32 is located on the bottom wall of the box 1. It is V-shaped, with the tip of the V aligned with the centerline of the fiber path area 5. The ends of the second aluminum plate 32 are tilted upward, and the side walls of the second aluminum plate 32 are tilted at an angle α.

[0030] For the fibers processed in this embodiment, the thickness of the fibers is a mm and the density is b bundles / cm 3, the tex value t of each fiber bundle is 1200-9600tex / bundle;

[0031] in, △R is the ratio of the reflectivity of the glass-ceramic sheet after attenuation to the baseline reflectivity without attenuation, and k is the proportional constant; k is the proportional constant, which is 3.7*10 -8 ;

[0032] △R' is the ratio of the reflectivity of the glass-ceramic sheet after attenuation to the baseline reflectivity without attenuation, and k' is the proportional constant, which is 6.0*10 -8 .

[0033] In this embodiment, the fiber parameters that need to be dehumidified are as follows: the fiber thickness a is 100-200 mm, and the density b is 25-50 bundles / cm 3 .

[0034] The values ​​of α and β for each example are shown in Table 1.

[0035] Table 1 α and β values ​​of the examples

[0036] Example α β △R preset value △R' preset value a b t Example 1 29.5 48 0.9 0.9 200 50 8400 Example 2 6.5 10 0.95 0.95 150 25 2400 Example 3 14.5 24 0.97 0.97 100 25 4800 Example 4 7 12 0.97 0.97 100 25 2400

[0037] This embodiment also discloses a dehumidification process. The surface of the fiber to be dehumidified in each embodiment is coated with a sizing agent. In this embodiment, the sizing agent is purchased from Taishan Fiberglass, brand: ECS303, and the amount used is 0.8% of the fiber mass. In addition, the profile of this embodiment adopts a continuous pultrusion process. The glass fibers are arranged reasonably according to the yarn drawing and then pass through the yarn guide plate into the dehumidification box. The volume fraction of the glass fibers in this embodiment is 65%. The isocyanate used in this embodiment is from Wanhua Chemical Group. 82681, a mixture of polyol-modified diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate; polyether polyol is a product of Wanhua Chemical Group. Product 650, a composite polyether used in the preparation of polyurethane pultrusion composites, is a milky white liquid at room temperature. Profiles are of uniform cross-section, measuring 105 x 6 mm.

[0038] The following examples provide specific descriptions.

[0039] Example 1

[0040] A dehumidification process includes the following steps: the fiber pulled out by the yarn guide plate passes through a dehumidification box, wherein the temperature of the dehumidification box is 80°C, the fiber pulling speed is 0.5m / min, and the drying distance, that is, the distance the fiber passes in the dehumidification box is 10mm.

[0041] Furthermore, the dehumidified fibers are sequentially subjected to glue injection, extrusion molding, curing, pulling, and cutting to obtain products, wherein the glue injection, extrusion molding, and curing processes are as follows: isocyanate and polyester polyol are added to the A / B barrels of the glue injection machine in a mass ratio of 90:10, respectively. The glue injection machine adopts a constant flow mode for stable glue injection. The temperature of the front zone of the pultrusion die is set to 190°C, the rear zone is set to 105°C, and the pultrusion speed is 0.5 m / min.

[0042] Example 2

[0043] A dehumidification process includes the following steps: passing the fiber drawn out by the yarn guide plate through a dehumidification box, wherein the temperature of the dehumidification box is 200°C, the fiber drawing speed is 0.6m / min, and the drying distance, i.e. the distance the fiber passes through the dehumidification box, is 500mm.

[0044] Furthermore, the dehumidified fibers are sequentially subjected to glue injection, extrusion molding, curing, pulling, and cutting to obtain products, wherein the glue injection, extrusion molding, and curing processes are as follows: isocyanate and polyester polyol are added to the A / B barrels of the glue injection machine in a mass ratio of 80:20, respectively. The glue injection machine adopts a constant flow mode for stable glue injection. The temperature of the front zone of the pultrusion die is set to 200°C, the rear zone is set to 110°C, and the pultrusion speed is 0.6 m / min.

[0045] Example 3

[0046] A dehumidification process includes the following steps: the fiber pulled out by the yarn guide plate passes through a dehumidification box, wherein the temperature of the dehumidification box is 120°C, the fiber pulling speed is 0.6m / min, and the drying distance, that is, the distance the fiber passes in the dehumidification box is 50mm.

[0047] Furthermore, the dehumidified fibers are sequentially subjected to glue injection, extrusion molding, curing, pulling, and cutting to obtain products, wherein the glue injection, extrusion molding, and curing processes are as follows: isocyanate and polyester polyol are added to the A / B barrels of the glue injection machine in a mass ratio of 80:20, respectively. The glue injection machine adopts a constant flow mode for stable glue injection. The temperature of the front zone of the pultrusion die is set to 200°C, the rear zone is set to 110°C, and the pultrusion speed is 0.6 m / min.

[0048] Example 4

[0049] A dehumidification process includes the following steps: passing the fiber pulled out by the yarn guide plate through a dehumidification box, wherein the temperature of the dehumidification box is 150°C, the fiber pulling speed is 0.65m / min, and the drying distance, that is, the distance the fiber passes through the dehumidification box is 200mm.

[0050] Furthermore, the dehumidified fibers are sequentially subjected to glue injection, extrusion molding, curing, pulling, and cutting to obtain products, wherein the glue injection, extrusion molding, and curing processes are as follows: isocyanate and polyester polyol are added to the A / B barrels of the glue injection machine in a mass ratio of 90:10, respectively. The glue injection machine adopts a constant flow mode for stable glue injection. The temperature of the front zone of the pultrusion mold is set to 195°C, the rear zone is set to 120°C, and the pultrusion speed is 0.65 m / min.

[0051] Comparative Example

[0052] The difference between Comparative Example 1 and Example 1 is that the fibers are directly injected with glue, extruded and molded, and cured without passing through a dehumidification box.

[0053] The difference between Comparative Example 2 and Example 1 is that the mirror aluminum plate has no tilt angle, and the mirror aluminum plate and the micro-ceramic glass sheet are located on the same rectangular straight side wall.

[0054] The difference between Comparative Example 3 and Example 1 is that the inclination angle α of the first aluminum plate is 20°, and the inclination angle β of the second aluminum plate is 30°.

[0055] Performance testing

[0056] The properties of the fibers treated in the examples and comparative examples and the resulting pultruded profiles were tested. The details are as follows:

[0057] (1) Detection of moisture content of fibers after dehumidification, where comparative example 1 detects fibers after passing through a yarn guide plate; (2) Bubble occurrence rate of pultruded profiles; (3) Mechanical properties of pultruded profiles; (4) Product qualification rate.

[0058] The test results are shown in Table 2.

[0059] Table 2: Test results of the embodiments and comparative examples

[0060]

[0061] From the performance test of the embodiment and the performance test of comparative example 1, it can be seen that, first of all, the dehumidification process of the present application can effectively achieve the initialization of the fiber. In addition, by comparing the performance of the embodiment and comparative example 2, it is found that in addition to the excellent dehumidification effect, the mechanical properties and product qualification rate of the final profile of the embodiment of the present application are uniform and very excellent. This is because, compared with the dehumidification box of comparative example 2, the inclination angles of the three mirror aluminum plates of the embodiment of the present application are determined according to the prescribed angle acquisition method, so that the performance of the profile product obtained by the embodiment is more excellent. This is because the dehumidification box of the embodiment of the present application is more uniform in heating the various parts of the fiber, making the sizing agent less likely to be destroyed, thereby contributing to the improvement of the performance of the profile. In addition, according to the performance of comparative example 3, it can be seen that the inclination angle of the mirror aluminum plate cannot be set arbitrarily, otherwise it may not be possible to achieve the effect of uniform heating of the fiber and non-destruction of the sizing agent.

[0062] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A continuous fiber dehumidification box for polyurethane resin, characterized in that: The invention comprises a box body with openings at both ends for fibers to pass through, a glass-ceramic sheet and a mirrored aluminum plate installed in the box body, wherein the glass-ceramic sheet is located on the inner wall of the box body in the direction of fiber thickness and is parallel to the surface in the direction of fiber thickness, and the mirrored aluminum plate is located on the side wall of the box body opposite to the glass-ceramic sheet and on the side walls of the box body on both sides of the glass-ceramic sheet. The mirrored aluminum plate and the glass-ceramic sheet enclose a dehumidification zone with openings at both ends and are parallel to the direction of fiber travel. The microcrystalline glass sheet is coated with graphene; both ends of the mirrored aluminum plate opposite to the microcrystalline glass sheet are tilted toward the microcrystalline glass sheet at an angle of α; the mirrored aluminum plates on both sides of the microcrystalline glass sheet are tilted away from each other at an angle of β near one end of the microcrystalline glass sheet; the fiber has a thickness of a mm and a density of b bundles / cm 3 , the tex value t of each fiber bundle is 1200-9600tex / bundle; in, △R is the ratio of the reflectivity of the glass-ceramic sheet after attenuation to the baseline reflectivity without attenuation, and k is the proportional constant, which is 3.7*10 -8 ; △R' is the ratio of the reflectivity of the glass-ceramic sheet after attenuation to the baseline reflectivity without attenuation, and k' is the proportional constant, which is 6.0*10 -8 .

2. A continuous fiber dehumidification box for polyurethane resin according to claim 1, characterized in that: The inclination angle α is 5-30°, and the inclination angle β is 1-50°.

3. The continuous fiber dehumidification box for polyurethane resin according to claim 1, characterized in that: The ranges of ΔR and ΔR' are: 0.9≤ΔR<1, 0.9≤ΔR'<1.

4. The continuous fiber dehumidification box for polyurethane resin according to claim 1, characterized in that: The graphene on the glass-ceramic sheet has a thickness of 10-200 μm and a roughness Ra of 1-50 μm.

5. The continuous fiber dehumidification box for polyurethane resin according to claim 1, characterized in that: Asbestos mesh is provided between the microcrystalline glass sheet and the box body, and between the mirror aluminum plate and the box body.

6. A dehumidification process using the continuous fiber dehumidification box for polyurethane resin according to any one of claims 1 to 5, characterized in that: The following steps are involved: The pulled fibers are passed through a dehumidification box.

7. A dehumidification process according to claim 6, characterized in that: The temperature of the dehumidification chamber is 80℃~200℃.

8. A dehumidification process according to claim 6, characterized in that: The fiber drawing speed is 0.4-2 m / min, and the drying distance is 1-500 mm.

Images