44results about How to "Appropriate bulk density" patented technology

A method for preparing a polyolefin resin powder has the steps ofa) heat dissolving a polyolefin resin in an organic solvent having a solubility parameter less than or equal to the solubility parameter of the polyolefin resin to obtain a polyolefin resin solution;b) cooling the polyolefin resin solution to precipitate a solid, thereby obtaining a solid-liquid mixture;c) optionally adding an adjuvant to the solid-liquid mixture and mixing; andd) conducting solid-liquid separation and drying to obtain a polyolefin resin powder suitable for selective laser sintering.The difference between the solubility parameters of the organic solvent and of the polyolefin resin is within 0-20% of the solubility parameter of the polyolefin resin.The polyolefin resin powder obtained according to this method has good antioxidant property, good powder flowability, moderate size, smooth surface, suitable bulk density, and suitable dispersibility and particle size distribution.

The invention discloses polypropylene powder for selective laser sintering and a preparation method thereof. The polypropylene powder for selective laser sintering is prepared from the following raw materials in parts by weight: 100 parts of a polypropylene solvent, 0.1-60 parts of polypropylene, 100-400 parts of a polar solvent, 0.1-4 parts of an emulsifier, 0.01-0.2 part of an antioxidant and 0.001-20 parts of an auxiliary agent. The preparation method comprises the following step of adding an emulsifier polar solution into a high temperature polypropylene solution for phase reversion emulsification to prepare micron spherical polypropylene powder. The preparation method is simple in step and easy to operate, and can obtain the polypropylene powder suitable for selective laser sintering in shape and character. Compared with existing polypropylene powder for SLS, the sphericility and the flowability are remarkably enhanced, and the prepared polypropylene powder is high in sphericility and power flowability and is quite smooth in surface. The polypropylene powder for a selective laser sintering technology can be easily used to prepare a mold product which is small in dimensional error, few in holes, uniform in shape and good in mechanical property.

The invention provides a preparation method of an antistatic polylactic resin powder used for selective laser sintering. The method comprises the following steps: 1, dissolving polylactic resin in a ketone and / or ether organic solvent at a heating temperature to obtain a polylactic resin solution; 2, cooling the polylactic resin obtained in step 1 to precipitate a solid precipitate; and 3, adding assistants to a solid-liquid mixture obtained in step 2, uniformly mixing the solid-liquid mixture and the assistants, and drying the obtained mixture to obtain the powder, wherein the assistants comprise an antistatic agent, an antioxidant and a powdery isolating agent. The method has the advantages of simplicity in operation, easiness in operation, provision of a sintering raw material with excellent processing properties for the selective laser sintering, and provision of a new direction for processing and application of functional polylactic resin. The invention further provides the antistatic polylactic resin powder prepared through the method, and a selective sintering method adopting the antistatic polylactic resin powder as a sintering powder raw material.

A method for preparing an aliphatic polyester resin powder includes the steps ofa) heat dissolving a crystalline aliphatic polyester resin in an organic solvent to obtain an aliphatic polyester resin solution;b) cooling the aliphatic polyester resin solution to precipitate a solid, thereby obtaining a solid-liquid mixture;c) optionally adding an adjuvant to the solid-liquid mixture and mixing; andd) conducting solid-liquid separation and drying to obtain an aliphatic polyester resin powder suitable for selective laser sintering.The crystalline aliphatic polyester resin powder obtained has good antioxidant property, good powder flowability, moderate size, smooth surface, suitable bulk density, and suitable dispersibility and particle size distribution. The aliphatic polyester resin powder is particularly suitable for selective laser sintering method.

The invention discloses a spinach culture medium as well as a preparation method and an application thereof. The spinach culture medium comprises vinegar residues and seaweed slags. The spinach culture medium disclosed by the invention has the advantages that by using industrial and agricultural wastes, a soilless culture medium is produced through high-temperature fermentation, thereby turning waste into wealth and turning the harm into benefits. The spinach culture medium has the characteristics of sufficient nutrition, good water absorption and ventilation property, moisture and fertilizer conservation and moderate volume-weight, and pH and EC (Electrical Conductivity) values suitable for growth of spinach, and can be used for effectively improving the dry and fresh weight of the overground part of spinach, remarkably reducing the contents of nitrate and nitrite in blades, improving the contents of soluble proteins and organic acids and improving the quality of spinach.