51results about How to "Improve endurance" patented technology

The invention discloses a water-based lithium battery positive electrode adhesive, a preparation method and application. The adhesive is of a single-layer or multi-layer shell core-shell structure formed by polar monomers such as acrylic acid, acrylate monomers, cross-linking monomers, self-emulsifying monomers and water through core-shell emulsion polymerization; by controlling the mass percent of acrylate monomers, polar groups and the like in the core layer structure and the shell layer structure and selecting proper types and dosages of cross-linking monomers and self-emulsifying monomers, the adhesive has proper surface tension, shows excellent adhesion and wettability to the current collector, has high peel strength, and is suitable for the current collector. According to the present invention, the lithium ion battery pole piece has the low glass-transition temperature so as to ensure the high toughness, the high surface density, the excellent electrolyte resistance, the excellent electrical property, the excellent coating property and the like of the pole piece, and the raw materials are all non-fluorine materials so as not to produce hydrogen fluoride and other harmful gases during the lithium battery recovery; water is used as a solvent, recycling is not needed, environment friendliness and low carbon are achieved, the manufacturing process is simplified, and the application range is widened.

The present invention discloses a laminating and pressing process for a special-shaped sheet material and a film, comprising a base, the top of which is fixedly connected to a support frame, and further comprising: a hydraulic cylinder, which is fixedly connected to the top of the support frame, the bottom end of which is fixedly connected to a lifting plate, the bottom of which is fixedly connected to a pressing plate, the top of which is fixedly connected to a fixing plate, and the top of which is fixedly connected to a blowing assembly; and a mounting assembly, which is slidably connected to the top of the base, and the present invention relates to the field of laminating and pressing technology. The laminating and pressing process for a special-shaped sheet material and a film can control the extrusion of the pressing plate on the film, and prevent the situation where the pressing is not transmitted due to insufficient contact when the pressing plate contacts the film, thereby ensuring the accuracy of the pressing of the pressing plate on the film, and the auxiliary assembly can roll the film after the pressing of the mounting assembly on the base, and prevent the auxiliary assembly from contacting the film with excessive force, which may cause damage to the film.

The application relates to the technical field of machining equipment, in particular to a deep drilling device for elbow curved rods, which comprises an assembling shell, a hydraulic cylinder is embedded at the top end of the assembling shell, a pressing mechanism is connected to the power output end of the hydraulic cylinder, and a sliding groove is arranged on the abutting surface of the assembling shell and the pressing mechanism. The winding equipment body winds and unwinds the cable, so that the electromagnet connected with the connector through the thread is penetrated into the rod piece. When the hydraulic rod drives the inclined block to press and bend the rod piece, the bearing capacity is improved through the support of the electromagnet, so that the excessive pressing and bending of the rod piece is avoided, the deformation of the rod piece is avoided, the product quality is affected, the electromagnet is connected with the connector through the thread, the electromagnet is convenient to disassemble and assemble, the electromagnet with the diameter size suitable for the rod piece is replaced, the applicability is improved, the rod piece is conveniently attracted after the electromagnet is electrified through the cable, the sliding condition is avoided, the pressing and bending quality is affected, when the electromagnet is not worked, the connector is tightened in the connecting hole through the winding equipment body, and the rod piece is conveniently placed and corresponds to the electromagnet.

The utility model discloses an anti-static and anti-fouling plastic packaging film which is wound on a wind-up roller and comprises a body, the body comprises a body upper layer, a tensile layer and a body lower layer, the body upper layer is adhered to the upper side of the tensile layer, the body lower layer is adhered to the lower side of the tensile layer, and the body upper layer is adhered to the lower side of the tensile layer. The tensile layer comprises two reinforcing ribs and an anti-cutting face, the anti-cutting face is arranged between the two reinforcing ribs, the probability that the body is punctured can be reduced through the anti-cutting face in the tensile layer, and the problem that one corner of a packaged object is exposed outside, so that the packaged object is collided and even soaked by rainwater, and the internal object is damaged is solved. By means of the structure, waste of the packaging film can be avoided, meanwhile, time wasted by re-wrapping can be avoided, meanwhile, the two reinforcing ribs can be used for reducing the possibility that when a small object is wrapped, the body is tightened forcibly so as to ensure that the body is fractured during tight wrapping, and meanwhile the reinforcing ribs can also be used for reducing the possibility that the body is transversely pulled to be broken.

The present invention provides a circular hollow sealing ring for nuclear power valves, belonging to the technical field of sealing rings; comprising a sealing ring body, the sealing ring body comprising an outer ring and an inner ring, the inner ring of the sealing ring body being provided with an inner sealing ring, the inner sealing ring being solidly provided, the inner sealing ring being made of flexible graphite packing, the outer ring of the sealing ring body being provided with an installation groove, the interior of the installation groove being provided with a middle sealing ring, the upper part of the middle sealing ring being provided with a top sealing ring, and the lower part of the middle sealing ring being provided with a bottom sealing ring. The present invention can automatically repair the sealing ring through a high temperature or high pressure environment when the sealing ring is micro-cracked or damaged, thereby improving the life and reliability of the sealing ring, extending the service life of the sealing ring, and improving its performance under extreme temperatures, while adding a radiation absorbent to improve the radiation aging resistance of the sealing ring, thereby enhancing the radiation tolerance of the sealing ring.

The application belongs to the technical field of waterborne polyurethane preparation, and particularly relates to a solvent-free photocuring polyurethane and a preparation method thereof, which comprises the following steps: 1) mixing 1,6-hexane diisocyanate trimer, hydroxypropyl acrylate and a polymerization inhibitor at 55-65 DEG C, and obtaining a PUA prepolymer after reaction; 2) mixing the PUA prepolymer, epoxy acrylate resin, hydrogenated rosin glyceride, an active diluent mixture containing a photoinitiator, PETMP, a tertiary amine type co-initiator, a silane coupling agent and a polymerization inhibitor, stirring, defoaming, filtering, and obtaining the solvent-free photocuring polyurethane; the application has the advantages of fast curing speed and high storage stability.

The utility model discloses a U-shaped pipe with an anti-deformation function, and belongs to the technical field of U-shaped pipe positioning. The protective device comprises a U-shaped pipe, a protective rack and a pipeline stabilizing mechanism, the pipeline stabilizing mechanism is arranged at the bottom of the U-shaped pipe, the protective rack comprises a vertical plate, the top and the bottom of the vertical plate are connected with a transverse plate, wrapping sleeves are arranged on the two sides of the transverse plate, a connecting mechanism comprises first connecting plates, and the first connecting plates are fixedly connected to the two sides of the front face and the back face of the transverse plate. By arranging the connecting mechanism, the transverse plate and the wrapping sleeve are connected, the U-shaped pipe is fixed through the transverse plate and the wrapping sleeve, the fixing shell can be fixed through the fixing mechanism, the U-shaped pipe is positioned through the fixing shell, the phenomenon that the U-shaped pipe shakes is prevented, the bearing capacity of the U-shaped pipe can be increased when an operator uses the U-shaped pipe for a long time, and the U-shaped pipe is prevented from shaking. The phenomenon that the U-shaped pipe deforms due to the influence of various forces is avoided, and deformation of the U-shaped pipe can be prevented.

The utility model discloses a double-layer packaging bag, which belongs to the technical field of packaging bags and comprises a bag main body and a handle, a fixing hole is arranged on the main body, a fixing ring is fixedly arranged in the fixing hole, one end of the handle is fixedly connected onto the fixing ring, the other end of the handle is detachably connected onto the fixing ring, and the handle is fixedly connected onto the main body. The main body is fixedly connected with a connecting piece, the connecting piece and the main body are integrally formed, a reinforcing layer is fixedly arranged in the main body and located between the connecting piece and the main body, and a first waterproof layer is fixedly arranged on the side, away from the reinforcing layer, of the main body; and a second waterproof layer is fixedly arranged on one side, far away from the main body, of the reinforcing layer. The packaging bag has the advantage that the service life of the packaging bag is prolonged.

The utility model relates to high pressure container technical field discloses a kind of transport vehicle LNG gas cylinder suitable for complex environment, including shell, the outside of shell is provided with buffer mechanism, the buffer mechanism is used to slow down inertia effect, the left side fixedly connected with sealing cover of shell, the bottom of shell is provided with fixed mechanism, the fixed mechanism is used to connect car body, the outside of sealing cover is provided with sealing mechanism, the bottom of shell is provided with heat exchange mechanism, the buffer mechanism includes two fixed rings, the inner wall of two fixed rings is fixedly connected in the outer wall of shell.In the utility model, the shell of gas cylinder is fixed by fixed ring, the cross rib provides support, the horizontal plate and side plate are connected with damping parts, front and back vibration is transmitted to hydraulic cylinder by hydraulic rod, while spring contraction slows down stress, reduces the vibration transmission and stress accumulation of vehicle, avoids temperature influence, improves the stability of whole.

The present invention discloses an intelligent material feeding device for an unwinding and leveling machine, comprising a base, the base having a clamping base, and a fixed clamping frame installed on the outer walls on both sides of the base, a grab frame fixedly connected to the top of the base, and a conveyor belt fixedly connected to the bottom of the inner walls on both sides of the grab frame; a feeding roller, the feeding roller having a rotating motor, and mounting plates arranged at both ends of the feeding roller and adapted to the grab frame, the mounting plates extending to the outside of the grab frame, and the bottom of the mounting plates installed on the base, the present invention relates to the technical field of unwinding and leveling machines. The intelligent material feeding device for an unwinding and leveling machine makes it difficult to affect the movement of the raw material when a gap appears between the raw material and the conveyor belt, thereby improving the overall processing efficiency of the device, the collection box is slidably connected to the base, so that the collection box can clean the collected impurities after the processing is completed, thereby increasing the bearing capacity of the collection device, thereby improving the overall processing efficiency of the device.

The utility model discloses a glass cutting surface polishing device, relates to the technical field of glass polishing devices, and aims to solve the technical problem that one pressed side of glass is easy to crack in the polishing process due to the fact that a current clamping structure horizontally clamps and fixes the glass and has no buffer space. Two polishing driving mechanisms are fixedly arranged on the upper surface of the fixing table and are symmetrically arranged, and through the design of the first buffering piece and the second buffering piece, the buffering space is increased while the effect of stably clamping and limiting glass can be kept; and when the glass is pressed in the polishing process, the hollowed-out pads in the same direction can be extruded to contract and incline, so that the protectiveness of the glass can be improved. The glass clamping device has the advantages that after the glass is clamped, the glass has a certain inclined effect, the probability of cracking caused by direct pressure in the polishing process is reduced, and the glass polishing protection is improved.

This utility model relates to a translational bending mechanism, comprising two sets of flipping seats, a tool holder, and a translational drive element. The two sets of flipping seats are movably and rotatably mounted on a frame at the bending center, and each set of flipping seats has a guide rod assembly on its inner side. The two ends of the tool holder are movably mounted on the guide rod assembly, and a tool is fixedly mounted on the top of the tool holder. The translational drive element is fixedly mounted on the flipping seat, and its output end is fixedly connected to the tool holder to drive the tool holder to move. This utility model uses the translational drive element and guide rod assembly to drive the tool to translate a certain distance during the flipping process, fine-tuning the tool's position and thus preventing the tool from colliding with the positioning table or bottom tool after flipping 180°.

The invention relates to application of sulfated glycogen synthase kinase-3 in prevention and treatment of liver insulin resistance. Specifically, the invention provides an application of a hyposulfated GSK-3beta inhibitor in preparation of a medicine, and the medicine is used for preventing or treating insulin resistance; the invention further discloses application of the GSK-3beta knockout reagent in preparation of a medicine. The medicine is used for preventing or treating insulin resistance.

The invention discloses a soothing gel composition and a preparation method thereof, and belongs to the technical field of gel. The soothing gel composition comprises the following components based on the total mass of the soothing gel composition: 8.5000% of a humectant; 5.9000% of a skin conditioning agent; 2.0000% of a surface active agent; 0.5300% of a thickening agent; 0.2000% of an astringent; 0.0800% of a preservative; 0.0500% of a repairing agent; 0.0003% of a coloring agent; 0.1130% of a soothing factor; 82.6267% of a solvent; the soothing factor is prepared from an abelmoschus esculentus flower extract, aloe barbadensis leaf juice, a scenedesmus sibiricus extract, a kalimeris crassifolia extract and sclerotium gum; the soothing effect of the soothing gel composition is improved through the synergistic interaction effect of the mallow flower extract, the aloe barbadensis leaf juice, the scenedesmus western extract, the kalimeris crassifolia extract and the sclerotium rolfsii gum.

The invention provides a water-based pole piece edge sealing insulating adhesive, a preparation method and application. The water-based pole piece edge sealing insulating adhesive has a core-shell structure which takes polyacrylic acid and ester thereof as a core and takes a PAA macromolecular structure fragment as a single-layer or multi-layer shell; a plurality of monomers including acrylic acid, acrylic ester, styrene, polar monomers, self-emulsifying monomers and crosslinking monomers are used as raw materials and are subjected to core-shell emulsion polymerization to prepare the emulsion. Wherein the proportion of the polar group is 5-30%, and the proportion of the self-emulsifying group is 1-8%. By selecting monomer raw materials and controlling the proportion, the prepared adhesive has proper surface tension and viscosity and has excellent infiltration and adhesion performance on current collector aluminum foil, especially oil-containing aluminum foil and inorganic filler, and the peel strength can reach 360 N / m; and the adhesive has a core-shell structure, so that the flexibility of the insulating coating is maintained, excellent low-absorption performance on electrolyte is achieved, and the performance of the battery is not influenced.

The utility model discloses a photovoltaic assembly lamination auxiliary tool, which relates to the technical field of photovoltaic assembly product production and comprises two side plates, a back glass assembly arranged on the inner sides of the two side plates, four reinforcing ribs arranged on the sides, close to the back glass assembly, of the two side plates respectively, and a glue containing groove arranged on the inner sides of the two side plates. The glue containing grooves are formed in gaps formed between the side plates and the reinforcing ribs and between the side plates and the back glass assembly, and the top plate is arranged at the tops of the two side plates. According to the photovoltaic module lamination auxiliary tool, through cooperation of the two side plates, the four reinforcing ribs and the top plate, the problems that an existing auxiliary tool is difficult to install, high in cost, high in plate explosion risk and the like are solved.

The utility model provides an air conditioner packaging structure, and relates to the technical field of air conditioner equipment. The air conditioner comprises an indoor unit and an outdoor unit. The air conditioner packaging structure comprises a protection lining plate and a protection piece. The protection lining plate is used for being arranged at the top or the bottom of the indoor unit or the outdoor unit, a clamping groove is formed in the protection lining plate, and the protection piece is clamped with the clamping groove and used for protecting the side portion of the indoor unit or the outdoor unit. According to the air conditioner packaging structure, the clamping groove is formed in the protection lining plate, the protection piece is connected with the clamping groove in a clamped mode, so that assembly or disassembly is convenient, in the installation state, the protection piece is located on the side portion of the indoor unit or the outdoor unit and can protect the side portion of the indoor unit or the outdoor unit, the bearing capacity and the protection performance of the air conditioner packaging structure are improved, and deformation of the indoor unit or the outdoor unit is effectively prevented.

The invention relates to a polypeptide with a blood sugar reducing effect. The amino acid sequence of the polypeptide is selected from one of IPVIA, IPVA, IPTA, IPVVA, IPVPA, VVPL, VPKPL, VPSL, IPPA, VIPL, VPAL, VPVVL, VPQ, VPIIL, HAYVFGVEDTLNALESGAIETL WENLDINR or YVFGVEDTLNALESGAIETL IVWENLDINR. The invention further relates to a preparation method of the polypeptide.

The invention belongs to the field of rubber processing and preparation, and particularly discloses anti-fatigue modified natural rubber for an aviation high-performance elastic bearing and a preparation method of the anti-fatigue modified natural rubber. The rubber for the aviation high-performance elastic bearing is designed and optimized from the aspects of rubber type selection, reinforcing filler modification, overall formula adjustment and the like, the comprehensive performance of the rubber is improved through strict raw material proportioning, rubber crosslinking density control and addition of a modified silicon dioxide filler and a catechin functional rubber additive into a rubber system, and the rubber has the advantages of high mechanical strength, high wear resistance, high wear resistance and the like. The prepared fatigue-resistant modified natural rubber has higher wear resistance, fatigue resistance, tensile strength, elongation at break and rebound value, and can better meet the use requirements of rubber for aviation high-performance elastic bearings. The rubber material provided by the invention is simple in preparation process, and the obtained rubber material is excellent in comprehensive performance, free of cracks in an ozone aging resistance test, relatively good in tensile strength, stress at definite elongation and elongation at break, high in tear strength and relatively good in wear resistance and fatigue resistance.

The application relates to a tensioning device for a building block screw rod and a tensioning method thereof, and the tensioning device comprises a stretching piece, a pressing piece, an extension piece and a driving piece; the stretching piece is used for being connected with a locking piece of the building block screw rod; the pressing piece is used for being connected with a threaded element of the building block screw rod; one end of the extension piece is connected with the stretching piece, and the other end of the extension piece is connected with the pressing piece; the driving piece is connected with the extension piece and is used for driving the extension piece to perform extension and retraction movements. Compared with the prior art, the stretching piece and the pressing piece only transmit axial force to the shaft core and the threaded element, the transmission efficiency of the tensioning force is high, compared with a radial tightening mode of a traditional torque wrench, no radial load is borne between the shaft core and the threaded element, and problems such as increase of a friction coefficient caused by torsional deformation of the threaded element and the shaft core spline are avoided.

This utility model discloses a building fire simulation training device, including an upper simulation area and a lower simulation area, both constructed using shipping containers. The lower simulation area includes a furniture fire simulation training room, a kitchen fire simulation training room, an electrical fire simulation training room, and an oil fire simulation training room. The outer wall of the oil fire simulation training room has a gas storage chamber, and a gas delivery pipeline is installed on the gas storage chamber, one end of which is connected to the gas storage chamber. The gas delivery pipeline surrounds the outer wall of the lower simulation area. A bed fire model is installed in the furniture fire simulation training room directly opposite the igniter; a kitchen fire model is installed in the kitchen fire simulation training room directly opposite the igniter; and an electrical fire model is installed in the electrical fire simulation training room directly opposite the igniter. This utility model provides a variety of training scenarios and good training results, with the upper simulation area used for comprehensive fire simulation training and the lower simulation area used for real fire simulation training.

The invention discloses an application of a MtCIPK12 gene in regulating plant resistance to low-iron stress and riboflavin synthesis, comprising: step one, obtaining a plant mutant by reducing the expression of a MtCIPK12 gene and a MtCIPK12 protein of a wild-type plant; the amino acid sequences of the MtCIPK12 gene and the MtCIPK12 protein are sequence 1 and sequence 2; step two, observing the expression and function of key enzyme genes in the riboflavin biosynthesis process of the plant mutant under iron deficiency; step three, increasing the accumulation of riboflavin in the plant mutant, and enhancing the stress resistance to low-iron stress; the MtCIPK12 gene mutant material has a stronger low-iron resistance, that is, exhibits lower leaf yellowing, higher leaf and root biomass, higher iron content, and higher riboflavin accumulation, proving that the MtCIPK12 gene mutation can improve the plant's resistance to low-iron stress and improve the plant's riboflavin content.

The utility model discloses an automobile engine cover plate with a protection structure, which comprises a cover plate main plate body, the front end of the cover plate main plate body is fixedly connected with a cover plate front decorative surface, and the rear end of the cover plate front decorative surface is provided with an impact protection component used for enhancing the strength of the cover plate main plate body. According to the automobile engine cover plate with the protection structure, the left reinforcing steel sheet, the right reinforcing steel sheet, the upper transverse reinforcing steel bar, the lower transverse reinforcing steel bar and the vertical reinforcing steel bar are arranged, so that when the automobile engine cover plate is used, the left reinforcing steel sheet, the right reinforcing steel sheet, the upper transverse reinforcing steel bar and the lower transverse reinforcing steel bar are arranged between the cover plate main plate body and the cover plate front facing; the left reinforcing steel sheet, the right reinforcing steel sheet, the upper transverse reinforcing steel bar, the lower transverse reinforcing steel bar and the vertical reinforcing steel bar form a steel reinforcing layer, the cover plate main plate body, the cover plate front decorative face and the steel reinforcing layer form a composite structure, when the top is hit, the bearing capacity can be increased, damage to an engine is reduced, the function of internally reinforcing and improving the protection performance is achieved, and the service life of the engine is prolonged. The problem that the device does not have the function of internally reinforcing and improving the protection performance is solved.

The invention discloses a lithium battery positive electrode adhesive, a preparation method and application, the adhesive is of a multi-layer core-shell structure formed by self-suspension core-shell polymerization of a low-Tg monomer, a high-Tg monomer, a crosslinking monomer, a reactive emulsifying monomer and an initiator, the low-Tg monomer is buried in an inner layer core, the high-Tg monomer is made into a shell part, and the shell is kept as a hard monomer, so that the core-shell structure is formed. According to the present invention, by controlling the proportion of the acrylic ester soft monomer in the core layer structure, the adhesive has the low Tg characteristic, the flexibility and the high surface density of the prepared pole piece are ensured, and by reasonably setting the proportions of the polar group, the polar monomer and the non-polar monomer and the like, the dissolution selectivity of the adhesive is regulated and controlled so as to improve the stability of the prepared adhesive; the adhesive has proper surface tension, shows excellent adhesion and wettability, high peel strength, excellent electrolyte resistance, electrical property, coating property and the like on the current collector, is environment-friendly and low-carbon, and enlarges the application range.

The hot-pressing type cooked food processing slitting equipment comprises an equipment body, an operation panel is fixedly connected to the front face of the equipment body, placing devices are fixedly connected to the two sides of the top of the equipment body, and sealing box doors are rotatably connected to the front faces of the placing devices; and a lifting blocking piece is slidably connected to the middle of the outer wall of the right side of the containing device, and fetching frames are slidably connected to the two sides of the bottom of the lifting blocking piece. According to the hot-pressing type cooked food processing and slitting equipment and the slitting method thereof, the taking frame is matched with the lifting blocking piece, food can be conveniently conveyed to the taking frame, a user does not need to stretch hands into the placing device when taking the food, and therefore the situation that the user is scalded due to the fact that the user makes contact with the high temperature in the placing device is avoided; and damage to contact parts caused by collision between the smearing roller and the transmission device in the moving process is effectively avoided.

The utility model provides a cast-in-place box girder, which relates to the technical field of girder boxes and comprises an outer frame, spacing components and V-shaped plates, the spacing components are arranged in the outer frame and divide the inner part of the outer frame into a plurality of sub-cavities, and a plurality of V-shaped plates are arranged in each sub-cavity. The inner space of the outer frame is divided into a plurality of sub-cavities by the spacing components, and a plurality of V-shaped plates are arranged in each sub-cavity, so that the borne pressure is decomposed step by step, the bearing capacity is greatly improved, and different numbers of V-shaped plates can be arranged in each sub-cavity according to the actual stress condition, so that the overall bearing strength is improved.

The application discloses a kind of compound microbial inoculant for aquaculture and preparation process, belong to the technical field of microbial culture, including three strains are respectively carried out high-density fermentation culture, obtain high-density fermentation broth, the fermentation broth of bacillus subtilis and paracoccus denitrificans is mixed, and diatomite is added to carry out core adsorption, obtain core adsorbate, introduce lactobacillus fermenting liquid and sodium alginate solution and core adsorbate are mixed embedding, by calcium chloride hardening liquid and chitosan solution are carried out secondary crosslinking forming, and the core-shell structure wet microspheres are prepared, after wet microspheres and composite freeze-drying protective agent are mixed, two-stage vacuum freeze-drying is carried out, and the compound microbial inoculant is obtained, the compound microbial inoculant is put into aquaculture water group, and the purification effect is verified, the present application is realized by microencapsulation structure and two-stage freeze-drying process, realizes the layered three-dimensional purification and long-acting slow release of inoculant, solves the problem that inoculant is easily inactivated at room temperature, and improves the survival rate of aquaculture.

The utility model discloses a multi-layer spring low-frequency tuned mass damper, which comprises a structural frame, and a mass block guide component and a spring guide component are arranged on the structural frame; the stiffness system comprises at least one group of multi-layer springs, each group of multi-layer springs comprises at least two layers of springs which are connected in series up and down, and a spring limiting part is arranged between every two adjacent layers of springs; the mass block is mounted on the mounting plate; wherein the multiple layers of springs are supported below the mounting plate, the spring limiting component is in up-and-down sliding fit along the spring guide component, and the mounting plate is in up-and-down sliding fit along the mass block guide component. The damping effect is good and the overall size is small.

The present invention provides a surface-treated steel sheet having good corrosion resistance, in which the damage resistance, particularly the resistance to surface contact damage caused by contact between one surface and another surface, is further improved, the surface-treated steel sheet comprising: a plated layer on both surfaces of a steel sheet; a first colored coating film layer; and a second colored coating film layer, the ratio of the film thickness of the second colored coating film layer to the film thickness of the first colored coating film layer being 0.1 or more and 0.5 or less, the first colored coating film layer and the second colored coating film layer containing resin particles, the proportion of the number of the resin particles having a thickness of the film thickness of the first colored coating film layer or more being 1% or more and 30% or less, and the proportion of the number of the resin particles having a thickness of the film thickness of the second colored coating film layer or more being 50% or more and 100% or less.

The application discloses an aqueous secondary dispersion containing a copolymer P, which is synthesized from the following components: 1) a hydroxyl-containing hydrophobic polymer containing the following components as structural unit monomers: A1 hydroxyl-containing monomer, B1 acrylic ester monomer and / or vinylic monomer, and 2) a hydroxyl-containing hydrophilic polymer containing the following components as structural unit monomers: A2 hydroxyl-containing monomer, B2 acrylic ester monomer and / or vinylic monomer with a Tg of a homopolymer greater than 80 DEG C, C acrylic ester monomer with a Tg of a homopolymer below 80 DEG C, and D carboxyl-containing monomer. The dispersion has a high bubble-free film thickness, and other properties such as hardness and resistance are not obviously lost; meanwhile, the dispersion has good weather resistance and can tolerate low-humidity, especially high-temperature low-humidity construction environment. The application further discloses a preparation method and application of the dispersion.