48results about How to "Reduce carboxyl end content" patented technology

The invention belongs to the technical field of macromolecules, and particularly relates to a preparing method of branched biodegradable polyester. The preparing method includes the steps of conducting esterification reaction on dihydric alcohol, a branching aid, aromatic dibasic acid and aliphatic dibasic acid, adding a three-functional-group aziridine group compound after the reaction ends, andfinally conducting condensation polymerization to obtain the branched biodegradable polyester. The branched structure is introduced to polyester molecules sequentially through triethanolamine and thethree-functional-group aziridine group compound; meanwhile, since a tertiary amine structure is formed by triethanolamine and a secondary amine structure is formed by the three-functional-group aziridine group compound, a terminal carboxyl group can be restrained, and the content of the terminal carboxyl group of the material is remarkably reduced. The obtained branched biodegradable polyester ishigh in melt strength and excellent in anti-ageing performance, and the longitudinal and transverse difference between tensile strength and right-angle tearing strength is small.

The invention relates to a preparation method for polylactic acid polyol with a low acid value. The polylactic acid polyol is prepared from polylactic acid and cyclic carbonate by a reaction under the action of a catalyst. Compared with the prior art, the prepared polylactic acid polyol with a low acid value has the following advantages: the content of carboxyl end group is low, and the acid value is less than 3, so the reactiveness of polylactic acid polyol is reinforced, and facilitation to participation of polylactic acid polyol in a reaction in subsequent application is obtained. In addition, the preparation method provided by the invention has the characteristics of simple process, low production cost, no need of a solvent in the process of preparation, no discharge of three wastes, capability of large-scale production, etc.

The invention relates to the technical field of polyester high-molecular materials, and particularly relates to a low-carboxylated biodegradable polyester and a production method thereof. The low-carboxylated biodegradable polyester comprises1,6-adipic acid or / and terephthalic acid and 1,4-butanediol. According to the preparation method of the low-carboxylated biodegradable polyester, the content of carboxyl end groups in the polyester can be furthest reduced by adopting a compound titanium catalyst and a carboxyl scavenger to produce condensation polymerization in the later period of esterification; the catalytic activity of titanium catalyst can be controlled by adding chelate with stabilizing effect, so as to avoid the side degradation reaction caused by the high activity of the catalyst in the later period of condensation reaction and furthest reduce the side reaction in the later period of the condensation reaction, so that the low-carboxylated level of the finished polyester product can be guaranteed, other additives are not additionally needed for modifying the product, the content of carboxyl end groups in the product can be reduced, and the high production cost of the product can be avoided.

The invention belongs to the technical field of polyester preparation, and discloses a modified PET copolyester with high viscosity and a low terminal carboxyl group and a preparation method and application thereof. The copolyester contains the following ingredients in parts by weight: 100 parts of low-viscosity PET copolyester, 0.8-2.0 parts of oxazoline compound and 0.6-2.0 parts of a hydroxyl chain extender. The method prepares the high-viscosity modified PET copolyester by adding the oxazoline compound and the hydroxyl chain extender. The oxazoline compound is added to react with the terminal carboxyl group in resin, the terminal carboxyl group content of resin is reduced, therefore, the hot water resisting performance of resin is increased. The hydroxyl chain extender is added, the molecular weight of resin is increased, and the balance between a physical performance and a processing performance is achieved. The viscosity and the melt strength of the modified PET copolyester are increased, the content of terminal carboxyl group is reduced, and the hot water resisting performance is greatly increased. Moreover, the production method shortens the polycondensation time and the production cycle, effectively reduces the thermal degradation reaction, and also increases the output of equipment.

The invention discloses a composite esterification and polycondensation catalyst for preparing poly trimethylene terephthalate, wherein the composite catalyst is a composition containing titanium dioxide, silicon dioxide and molybdenum trioxide. The prepared PTT product has very low end carboxyl content, ether content and rather high characteristic viscosity.

The invention relates to the technical field of flame-retarding polyester thin film, and particularly relates to a phosphorus-containing flame retardant, a flame-retarding thin film and preparation methods thereof. In order to solve the problems of large flame retardant adding amount, low compatibility with a thin film substrate and unstable mechanical performance, the invention provides the phosphorus-containing flame retardant, the flame-retarding thin film and preparation methods thereof. The phosphorus-containing flame retardant has the following structural formula as shown in the specification, wherein the flame retardant has an oxazoline structure; R1 is alkylidene; and the number of C atoms is 2-6. The phosphorus-containing flame retardant has functions of expanding the chain and improving the viscosity of polyester molecules; and the flame-retarding polyester thin film with the flame retardant has high flame-retarding performance, relatively high mechanical property, high heat stability and higher light transmittance. The preparation methods are easy to operate and simple.

The invention discloses a polymerizing production method for transparent amorphous copolyester. The method has the advantages of low esterification temperature, short esterification time and high esterification rate. The method comprises the following steps of: carrying out an esterification reaction and a condensation reaction on dihydric alcohol and dicarboxylic acid to obtain the transparent amorphous copolyester, wherein the esterification reaction comprises the following specific procedures of: breaking various materials into pulp by using a pulping machine and carrying out the esterification reaction on the pulp at the temperature of 220-240DEG C for 1.0-1.5 hours to obtain an esterified product; the condensation reaction comprises the following specific procedures of: polymerizing the esterified product obtained by the esterification reaction at the reaction pressure of 0.2-0.5MPa and the temperature of 250-260DEG C for 1.5-2 hours; then reducing the pressure to be less than 200MPa within 0.5 hour; raising the condensation reaction temperature to be 275DEG C from 260DEG C; adding a thermal stabilizer; and after the condensation reaction, obtaining a polyester copolymer with the inherent viscosity of greater than 0.75dL / g and the carboxyl content of less than 10mol / t.

The invention belongs to the technology in the preparation field of completely biodegradable fat-aromatic copolyester and in particular relates to a preparation method of polyadipic acid-butylene terephthalate with high molecular weight. The preparation method comprises the following steps of: adding butanediol, adipic acid and terephthalic acid into a reactor; adding a composite catalyst to the reactor for carrying out esterification reaction; and carrying out polycondensation to obtain a product, wherein the composite catalyst is a mixture of metal oxide and titanium organic esters, and the metal oxide is at least one of oxides of Li, Na, K, Mg, Al, Ca, Mn and Co. The composite catalyst is adopted, so that the catalytic efficiency is high, the polymerization reaction velocity is greatly increased and the cost of the product is technically reduced. A stabilizer is added during the polycondensation stage, so that the high-temperature degradation side reaction is reduced, the molecular weight of the polymer is improved, the product color phase is improved, the terminal carboxyl content of the polymer is effectively reduced, the post-processing heat resistant performance of the product is improved, and the using value is greater.