1097 results about "Blowing agent" patented technology

The invention discloses a solvent-resistant foaming material and a preparation method thereof, and relates to the technical field of high-molecular compound rubber foaming materials. The solvent-resistant foaming material is prepared from the following raw materials in parts by mass: 90 parts of a basic polymer, 5-25 parts of a chemical foaming agent, 0.5-5 parts of a cross-linking agent, 0.5-8 parts of a foaming aid, 5-40 parts of filler, 10-30 parts of a solvent-resistant modifier, 0.5-5 parts of a processing aid and 0.5-1.5 parts of an anti-aging agent. Through the synergistic effect of the base polymer (the nitrile rubber and the butadiene rubber are mixed according to the ratio of 1: 1) and the solvent-resistant modifier (such as polytetrafluoroethylene powder), the problem that a traditional foaming material is easy to swell and deform in an organic solvent environment is solved. On the trend, the volume swelling rate and the mass change of the material in a solvent are effectively reduced, the infiltration resistance is enhanced, the structural integrity of the material is kept when the material is in contact with lubricating oil or an alcohol solvent for a long time, and therefore the service life of a sealing piece is prolonged.

The invention discloses a reclaimed oil bio-based plastic modified rubber material and a preparation method thereof, and the reclaimed oil bio-based plastic modified rubber material comprises the following components by weight: 30-70 parts of bio-based plastic, 10-40 parts of natural rubber, 5-25 parts of plant fiber, 5-50 parts of calcium powder, 0.3-1.5 parts of a vulcanizing agent, 0.8-2 parts of zinc oxide, 0.3-0.9 part of an accelerator, and 1-10 parts of a foaming agent. The invention relates to the technical field of rubber materials, in particular to an antibacterial and mildew-proof rubber material. The regenerated oil-based bio-based plastic is innovatively applied to modification of a rubber material, a new application way of the bio-based material in the field of rubber-plastic compounding is developed, a new thought is provided for solving the environmental and resource problems caused by a petroleum-based material, and the selection of the raw materials not only embodies effective utilization of renewable resources, but also has the advantages of environmental protection and environmental protection. The carbon emission is reduced, and the development trend of current green materials is met.

The invention provides a polyurethane material for leaking stoppage of coal mine spraying and a preparation method thereof, and belongs to the technical field of polyurethane. The preparation method comprises the following steps: pretreating a multi-walled carbon nanotube, coupling phytic acid and a silane coupling agent, reacting with UiO-66-NH2, coating the surface with a graphene oxide layer, mixing with polyether polyol, a catalyst and an antistatic agent, adding into water, adding a foaming agent and silicone oil, heating, stirring and mixing, transferring into a mold, adding diisocyanate, and after foaming is completed and the temperature of the material is reduced to room temperature, carrying out extrusion molding to obtain the composite material. And drying, heating and curing to obtain the polyurethane material for coal mine spraying air leakage stoppage. By adding the prepared wrinkled graphene oxide coated UiO-66-NH2 / modified multi-walled carbon nanotubes, the mechanical property and strength of the prepared polyurethane material for coal mine spraying air leakage stoppage can be obviously improved, the flame retardant property such as the oxygen index of the material is also obviously improved, the foam expansion is improved to a certain extent, the preparation method is simple, and the preparation method is suitable for industrial production. The flame-retardant and mechanical properties can be obviously improved, and the application prospect is wide.

The invention relates to the technical field of refrigeration material preparation, in particular to an efficient passive radiation refrigeration material suitable for a sub-super environment and a preparation method and application of the efficient passive radiation refrigeration material. The method comprises the following steps: uniformly mixing thermoplastic polyurethane, sunlight high-reflection inorganic particles and a phase change material in a solvent; after a chemical foaming agent is added, the obtained suspension liquid is heated and foamed in a confinement mold, and wet gel is formed; and finally, carrying out freeze drying treatment to obtain the composite porous aerogel. The prepared material has a micro-nano porous skeleton formed by TPU, and inorganic particles and PCM are uniformly dispersed in the skeleton wall. Through component cooperation and a special porous structure, the material has extremely high sunlight reflectivity and mid-infrared emissivity, self-adaptive temperature regulation and control are achieved through PCM phase change, the problem that refrigeration of a traditional material fails in the sub-environment such as the vertical surface is effectively solved, and efficient sub-super-environment heat management is achieved.

The invention discloses a high-toughness flame-retardant foaming type PVC wood-plastic plate and a preparation method thereof, and belongs to the technical field of building materials. The high-toughness flame-retardant foaming type PVC wood-plastic plate comprises the following components in percentage by mass: 30%-50% of PVC resin, 20%-40% of a polyurethane prepolymer, 5%-30% of wood fibers, 2%-10% of a nano filler, 2%-10% of a flame retardant, 1%-5% of a plasticizer, 0.5%-2% of a foaming agent and 0-1% of other auxiliaries, and the PVC resin and the polyurethane prepolymer form an interpenetrating network structure. According to the invention, the PVC resin and the polyurethane prepolymer are mixed according to a certain proportion to form a PVC / polyurethane interpenetrating network structure, which not only enhances the mechanical strength of the material, but also greatly improves the toughness and impact resistance of the material; the introduction of the nanofiller further enhances the interface bonding force and stress dispersion capability of the material.

The organosilicon-polyurethane foam encapsulating material is composed of a component A and a component B. The component A comprises sucrose initial polyether polyol, sorbitol initial polyether polyol, a water-containing alcohol amine foaming agent, a catalyst and a halogen-free flame retardant, and the component B comprises an NCO-terminated polysiloxane-polyurethane prepolymer, silicone oil and a diluent. Wherein the water-containing alcohol amine foaming agent comprises isopropyl alcohol di-sec-butyl alcohol amine, a mixture of isopropyl alcohol sec-butyl alcohol amine and water. The two-component encapsulating material is used for encapsulating a new energy battery module.

The invention relates to the field of high polymer materials, and discloses an environment-friendly building energy-saving sound insulation material and a preparation method thereof.The environment-friendly building energy-saving sound insulation material is prepared from, by weight, 100-120 parts of modified polyether polyol, 140-150 parts of isocyanate, 8-12 parts of modified hollow glass beads, 5-8 parts of modified sericite, 3-5 parts of ammonium polyphosphate, 2-4 parts of foaming agent, 1-3 parts of stabilizer and 0.1-0.5 part of catalyst; the modified polyether polyol is polyether polyol containing phosphorus and a phase change energy storage chain segment, the modified hollow glass beads are composite coupling agent surface modified hollow glass beads, the modified sericite is triazine flame retardant intercalation modified sericite, and the triazine flame retardant is a triazine derivative containing a siloxane structure and a DOPO structure. The rigid foaming polyurethane material is prepared from the modified polyether polyol and the isocyanate, and the modified hollow glass beads, the modified sericite and the ammonium polyphosphate are added, so that the material has excellent heat insulation and flame retardant properties and also has good mechanical properties.

The invention relates to a foamable composition comprising at least one epoxy resin, at least one hardener for epoxy resins, at least one chemical and / or physical blowing agent and at least one biogenic raw material, as well as their use as composite materials and a method for producing a foamed composition.

The invention belongs to the technical field of polyurethane, and particularly relates to a low-swelling-rate hydrophilic polyurethane sponge composite material as well as a preparation method and application thereof. The low-swelling-rate hydrophilic polyurethane sponge composite material is prepared from a component A and a component B according to the mass ratio of 100: (50-55), and the component A comprises the following raw materials: a foaming agent, wollastonite powder, an antibacterial agent, emulsifying wax and a polyether type cross-linking agent; the component B comprises polyether ester polyol and toluene diisocynate; the polyether type cross-linking agent is prepared by taking triethanolamine as an initiator and carrying out ring-opening polymerization reaction with EO; the polyether ester polyol is prepared by taking polyethylene glycol, diethylene glycol, trimethylolpropane and adipic acid as raw materials through esterification reaction. The hydrophilic polyurethane sponge prepared from the composite material is good in hydrophilicity, high in aperture ratio, fine and smooth in foam hole, low in swelling ratio and excellent in mechanical property.

The invention discloses a waterproof, anti-crack and moisture-proof self-healing material for a concrete structure and a preparation method thereof, relates to the technical field of concrete, and aims to solve the problems that the mixing degree is poor and the waterproof and moisture-proof effects are reduced due to the fact that various aggregates for improving the strength are added to an existing concrete structure in order to improve the anti-crack strength. The concrete is prepared from the following raw materials by weight: 30%-50% of cement; 5%-30% of sand; 5%-30% of stones; 5%-20% of a reinforcing material; 5%-10% of polymer modified asphalt; 1%-5% of a water reducing agent; 1%-5% of an additive; 1%-5% of a chemical self-healing agent; 1%-5% of a foaming agent; the additive is one or more of a concrete expansive agent, a rapid hardening agent, a plasticizer, a polyurethane type flexible agent and a concrete retarder, and the reinforcing material is one or more of microfibers, slag, fly ash, silane ash and a cellulose material. The cellulose material is one or more of wood, hemp, polypropylene fiber and polyester fiber.

The invention belongs to the technical field of high polymer materials for preparing tray products, and particularly relates to a high polymer material for preparing tray products as well as a preparation method and application of the high polymer material. The high polymer material for preparing the tray product is composed of a component A and a component B. The component A comprises the following raw materials: polyether polyol a, polyether polyol b, polyether polyol c, polyester polyol d, an auxiliary agent, a foam stabilizer, a catalyst, a chemical foaming agent and a flame retardant. And the component B is polymethylene polyphenyl polyisocyanate. According to the polyether polyol c disclosed by the invention, the flame retardant property, the compression strength and the dimensional stability of the material are improved; the high polymer material for preparing the tray product has load-bearing, wear-resistant and excellent flame-retardant properties, also has excellent dimensional stability, weather resistance and hydrolysis resistance, is applied to the tray product, is long in service life, can be recycled, and has a mothproof function; the invention also provides a preparation method thereof.

A blowing agent for obtaining a polyurea resin foam including a polyurea having a repeating unit represented by the following general formula (I), the blowing agent including a reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide. (In the formula I, R1 is a divalent hydrocarbon group having a cyclic structure optionally having a substituent, and R2 is a divalent hydrocarbon group optionally having a substituent.)

The invention discloses a colorful TPO interior foot pad skin and a preparation method thereof, and relates to the technical field of automobile interiors. The surface functional layer is used for improving wear resistance, the colorful pattern layer is used for presenting a visual effect, and one surface, far away from the base material layer, of the bottom layer structure is of a 3D net-shaped structure; the surface functional layer comprises matte water-based PUD resin, matte water-based PUA resin, a wear-resistant additive, a cross-linking agent and a diluent; the colorful pattern layer comprises water-based or solvent-based poly-carbon type polyurethane resin, water-based or solvent-based color paste and auxiliaries; the base material layer comprises modified TPO resin, nano calcium carbonate, a light stabilizing aid and a pigment; the bottom layer structure comprises modified TPE, an AC foaming agent and a DCP cross-linking agent; through the innovation of the composite structure, the colorful pattern layer design, the environment-friendly TPO base material, the net-shaped bottom layer structure and the like, on the basis of meeting functional requirements, light weight and personalized upgrading of the foot pad skin are achieved.

The invention discloses an environmentally friendly high-elastic polyurethane modified acrylic runway surface adhesive and a preparation method thereof, which solves the problems of insufficient compatibility and mechanical strength of a plastic runway prepared by using organosilicon modified polyurethane in the existing process, and easy shedding or stratification when the organosilicon is compounded with the polyurethane. The runway surface adhesive is composed of the following raw materials: water-based polyurethane emulsion, modified acrylate, modifier, flame retardant, antioxidant, crosslinking agent, auxiliary foaming agent and white oil. The invention provides an environmentally friendly high-elastic polyurethane modified acrylic runway surface adhesive, which uses water-based polyurethane emulsion and modified acrylate as base materials, and the method of modifying the water-based polyurethane emulsion by modified acrylate is more environmentally friendly, while the modifier in the raw materials ensures that the runway surface adhesive has high elasticity and crosslinking density, and the modifier and the auxiliary foaming agent cooperate with each other to significantly improve the foaming effect of the plastic runway, and help to generate uniform and dense bubbles inside the runway surface adhesive material.

The present invention relates to the technical field of polymer thermal insulation materials, and in particular to a flame retardant superior silicon thermal insulation material and a preparation method thereof. The flame retardant superior silicon thermal insulation material is prepared from component A, component B and component C; component A is prepared from the following raw materials in mass percentage: 19-28% polysilicon polyol containing catalyst II, 22-30% melamine polyether polyol, 5-10% crosslinking agent, 2-6% catalyst I, 8-15% liquid flame retardant, and 12-20% foaming agent; component B is polymerized isocyanate; component C is an inorganic flame retardant. The method of the present invention is to transfer component A, component B and component C into a mold or a laminator, and obtain them through foaming and maturation. The method of the present invention ensures that the prepared flame retardant superior silicon thermal insulation material achieves the corresponding flame retardant effect through polysilicon polyol, melamine polyether polyol, and the amount of flame retardant added, thereby solving the flammability problem of polyurethane rigid foam.

A process for producing foam particles composed of thermoplastic elastomers having polyamide segments, comprising the steps:(a) production of a suspension of pellets of the thermoplastic elastomer in a suspension medium,(b) addition of a blowing agent,(c) impregnation of the pellets with the blowing agent by heating of the suspension in a pressure vessel to an impregnation temperature IMT at an impregnation pressure IMP, depressurization of the suspension by emptying of the pressure vessel via a depressurization device and work-up of the foam particles obtained, and also foam particles obtainable by the process.

The invention discloses a powder blowing agent for powder spraying metallurgy and a preparation method and application thereof, and belongs to the technical field of alloy smelting. The powder blowing agent is prepared from the following elements in percentage by mass: 50.0 to 85.0 percent of Fe, 0 to 30.0 percent of Cr, 0 to 30.0 percent of Ni, 0 to 5.0 percent of W, 0.2 to 10.0 percent of RE, 0.1 to 8.0 percent of Ti, 0 to 10.0 percent of Si and 0.1 to 10.0 percent of O, the mass ratio relation of RE, Si, O and Ti meets the condition that (RE + Si + O) / Ti is (2: 1)-(50: 1); the RE and O elements exist in the powder blowing agent in a solid solution form; the RE is rare earth. The powder blowing agent is produced in a mechanical alloying mode, and the particle size range suitable for powder spraying metallurgy is selected through screening. The powder blowing agent can introduce solid solution oxygen into smelted steel, so that the comprehensive performance of the material is improved.

The invention discloses a skin-friendly antibacterial foaming material and application thereof in footwear products, and relates to the technical field of high polymer materials. When the skin-friendly antibacterial foaming material is prepared, firstly, tetramethyl tetravinyl cyclotetrasiloxane and a flame retardant react to obtain flame-retardant cyclosiloxane, 1, 3-bis (aminopropyl-1, 1, 3, 3-tetramethyl disiloxane and maleic anhydride react to obtain an end-capping reagent, the flame-retardant cyclosiloxane and octamethyl cyclotetrasiloxane are subjected to ring opening polymerization, and the skin-friendly antibacterial foaming material is obtained. Carrying out end-capping by an end-capping reagent to obtain functionalized polysiloxane, loading a foaming agent on hollow silicon dioxide, and grafting chitosan quaternary ammonium salt; and finally, polymerizing polyether amine, furan-2, 5-dimethyl dicarboxylate, 3, 5-diaminobenzene sulfonic acid and dimethyl malonate to prepare modified polyamide, and blending and foaming the modified polyamide, the functionalized polysiloxane, the modified silicon dioxide and chitosan quaternary ammonium salt to prepare the skin-friendly antibacterial foaming material. The prepared skin-friendly antibacterial foaming material has excellent flame retardance, antibacterial performance and self-repairing performance.

The invention relates to the technical field of preparation of phase-change materials, in particular to a steel slag-based porous ceramic composite phase-change material and a preparation method thereof.According to the preparation process, a sacrificial template method and a foaming agent pore-forming method are combined, waste polyurethane foam and waste wood pulp sponge are used as templates, industrial solid wastes (steel slag, fly ash and rice hull ash) are used as raw materials, and the steel slag-based porous ceramic composite phase-change material is prepared. The steel slag-based porous ceramic is prepared. The steel slag-based porous ceramic composite phase change material is prepared by using the prepared steel slag-based porous ceramic as a carrier vacuum adsorption phase change material. According to the invention, resource utilization of wastes is promoted, and environmental pollution caused by industrial solid wastes, biomass wastes and plastic wastes is reduced. The steel slag-based porous ceramic with abundant pore structures and the steel slag-based porous ceramic composite phase change material with good thermal performance and thermal cycle performance are prepared by adjusting the proportion of the raw materials, the porosity of the porous template and the impregnation vacuum degree. The preparation method is simple and suitable for large-scale production.

The invention belongs to the technical field of polyurethane elastomers, and particularly relates to an anti-static high-temperature-resistant polyurethane microporous elastomer and a preparation method thereof. Comprising a component A and a component B. The component A comprises conventional polyester polyol, functionalized polyester polyol, polyester polymer polyol, a chain extender, a cross-linking agent, a foam stabilizer, a foaming agent and a catalyst, and the component B comprises conventional polyester polyol, functionalized polyester polyol, polyether polyol and isocyanate. The functional polyester polyol is prepared by mixing activated carbon powder modified neopentyl glycol with straight-chain small-molecular dihydric alcohol and then carrying out esterification reaction on the mixture and dibasic acid. The prepared anti-static high-temperature-resistant polyurethane microporous elastomer has excellent conductivity and high-temperature resistance, and is good in skin, high in bearing capacity and high in thermal deformation temperature.

The invention discloses a heat-insulating non-combustible material as well as a preparation method and application thereof, and belongs to the technical field of heat-insulating non-combustible materials. The preparation method of the material comprises the following steps: (1) mixing and modifying an inorganic flame retardant and a surface modifier to obtain a modified inorganic flame retardant with the particle size of 100-500nm; (2) adding the modified inorganic flame retardant into the graphene oxide solution to obtain a graphene oxide coated modified inorganic flame retardant; (3) mixing 50-60 parts of polyether polyol, 20-30 parts of polyester polyol, 3-5 parts of a foam stabilizer, 2-3 parts of a catalyst, 15-18 parts of a foaming agent, 65-80 parts of modified expandable graphite, 150-200 parts of a graphene oxide coated modified inorganic flame retardant and 0.9-1.5 parts of water to obtain a mixed solution; and (4) adding 100-150 parts of diisocyanate into the mixed solution, stirring, pouring into a mold, foaming and curing, thereby obtaining the polyurethane foaming material. According to the heat-insulating non-combustible material, polyurethane is taken as a matrix, and the graphene-coated inorganic flame retardant is introduced, so that the heat retaining property, the mechanical property and the heat stability of the material are improved on the premise of ensuring the flame retardant property.

Isocyanate-reactive compositions and thermally insulating rigid polyurethane foams, such as those that can be used as a thermal insulation medium in the construction of refrigerated storage devices, are disclosed. The compositions include a halogenated olefin blowing agent and a polymer polyol. The polymer polyol includes (1) a base polyol having an OH number of at least 200 mg KOH / g; and (2) polymer particles dispersed in the base polymer, wherein the polymer particles comprise the reaction product of an ethylenically unsaturated composition comprising an ethylenically unsaturated fluorinated compound.

The invention belongs to the technical field of wind power generation blade filling materials, and particularly relates to a polyurethane foam filling material for a wind power generation blade and a preparation method and application of the polyurethane foam filling material. Wherein the component A comprises the following components: polyether polyol a, polyether polyol b, polyether polyol c, polyester polyol d, a viscosity reducer, a cross-linking agent, a foam stabilizer, a catalyst, chemical foaming agent water and an auxiliary agent; the component B is polymethylene polyphenyl polyisocyanate; the polyether polyol a is polyether polyol prepared by taking enzymatic hydrolysis lignin, pentaerythritol, trihydroxymethyl melamine and propylene glycol as initiators and carrying out a reaction; the polyether polyol b is polyether polyol which is prepared by taking bisphenol A and trimethylolpropane as initiators; the filling material prepared by the invention is safe, green and environment-friendly, has the advantages of low density, high strength, better process adaptability and excellent dimensional stability, and also can provide good weather resistance.

Disclosed herein are fluoroolefin compositions, methods of producing the same, methods and systems using the same, and systems containing the HFO-1234ze compositions. The inventive compositions are useful as refrigerants in air conditioning and refrigeration systems, and also as blowing agents.

The invention relates to a preparation method of a high-elastic wear-resistant rubber sole. Comprising the following steps: S1, uniformly mixing 50-60 parts by weight of epoxy resin, 10-20 parts by weight of a polyurethane-acrylate copolymer, 20-30 parts by weight of an elastic complex, 3-5 parts by weight of stearic acid, 1-4 parts by weight of zinc oxide, 3-5 parts by weight of zinc stearate and 2-4 parts by weight of zinc oxide; the preparation method comprises the following steps: uniformly mixing 1-3 parts by weight of magnesium oxide and 1-3 parts by weight of an AC foaming agent in an internal mixer at the temperature of 60-70 DEG C, internally mixing for 30-60 minutes, continuously mixing for 15-20 minutes at the temperature of 90-95 DEG C, granulating after open milling, and standing for 20-24 hours at room temperature to obtain a molding master batch; s2, putting the molding master batch into a foaming mold for compression molding, controlling the mold closing pressure to be 15-25MPa, then heating to 180-190 DEG C together with the foaming mold, performing vulcanization treatment for 8-15 minutes, cooling, and performing standing treatment at room temperature for 20-24 hours to obtain the high-elasticity wear-resistant rubber sole. According to the high-elastic wear-resistant rubber sole, the preparation method and the damping shoe, a good damping effect is achieved, and certain mechanical strength is achieved.

The invention discloses a closed-cell heat-conducting flame-retardant foamed silica gel material and a preparation method thereof in the field of organic silicon functional materials. The closed-cell heat-conducting flame-retardant foamed silica gel material is prepared from the following raw materials: basic silica gel, silane modified boron nitride, titanate modified aluminum hydroxide, a foaming agent, a cross-linking agent, a catalyst, an inhibitor and absolute ethyl alcohol. The raw materials are mixed according to a certain mass ratio. Wherein the silane modified boron nitride is prepared by heating, refluxing and reacting boron nitride powder and a silane coupling agent in an ethanol solvent and then drying; the titanate modified aluminum hydroxide is prepared by ultrasonically dispersing aluminum hydroxide powder and a titanate coupling agent in deionized water, adjusting the pH value, reacting and drying. The preparation method comprises the following steps: mixing the basic silica gel with the two modified fillers at a high speed, sequentially adding other raw materials, continuously mixing, transferring into a mold, pressurizing at a certain temperature to complete vulcanization foaming, taking out, washing with water, and drying in vacuum. According to the material, the interface bonding force is improved through the modified filler, and the material has the characteristics of high heat conductivity, high flame retardance and stable closed-cell structure.

The invention relates to the technical field of modified polyurethane preparation, in particular to a modified rigid polyurethane foam material and a preparation method thereof.The material is specifically prepared from CO2-based polyol, polyether, deionized water, a foaming agent, a catalyst, a foam stabilizer and isocyanate. Wherein CO2-based polyol is introduced into original polyether polyol, specifically, poly (ethylene carbonate) polyol is added, so that the heat conductivity coefficient of the material can be reduced, the compression strength of the material can be improved, and the low-cost and high-performance polyurethane foam can be prepared. The finally prepared rigid polyurethane foam material has the characteristics of good heat insulation property and high pressure resistance; and the whole preparation process is simple, the whole cost is low, and the market competitiveness is high.

Polyisocyanurate foam-forming compositions, polyisocyanurate foams, insulated assemblies, and method of making thereof are provided. The polyisocyanurate foam-forming composition comprises an organic polyisocyanate and an isocyanate-reactive composition. The isocyanate-reactive composition comprises a polyether polyol or polyester polyol with a nominal hydroxyl functionality of at least 2.0, a blowing agent composition, a trimerization catalyst composition, and a surfactant. The blowing agent is present in an amount sufficient to produce a polyisocyanurate foam from the isocyanate-reactive composition that has a density of less than 1.8 lb / ft3 (28.8 kg / m3). The blowing agent composition comprises a hydrocarbon or hydrocarbon blend in an amount of at least 6% by weight and water in an amount less than 0.2% by weight. The trimerization catalyst composition comprises an alkali metal carboxylate or an alkaline metal carboxylate and a solvent that is not isocyanate-reactive.

A house wrap for a building comprises a reinforcing drainage plane layer configured to face the outside of the building; a breathable, non-perforated barrier film bonded to the drainage plane layer; and at least one insulating layer including a perforated expanded low density polyethylene foam layer, wherein in the expanded low density polyethylene layer at least 80% of the blowing agents are dissipated from closed cells within the expanded low density polyethylene layer, forming evacuated closed cells whereby a partial vacuum is formed within the closed cells of the low density polyethylene layer.

An injection molding system is provided. A mixing unit is configured to mix a flowable polymeric material with a blowing agent to form a mixture. A fluid supply unit is configured to provide the blowing agent to the mixing unit. The fluid supply unit includes an injection outlet coupled to the mixing unit, a compressor configured to generate the blowing agent, an injection valve disposed between the injection outlet and the compressor and configured to receive the blowing agent from the compressor through a first passage, and a cleaning mechanism configured to clean the injection valve. The cleaning mechanism includes a control valve coupled to the compressor through a second passage and coupled to the injection valve through a third passage connected to the first passage, and an actuating device configured to actuate the control valve. The blowing agent is flowable to the injection valve through the control valve.