Abstract:
The invention relates to water-absorbing polymer particles with improved colour stability and to processes for preparing them, the water-absorbing polymer particles comprising at least one optical brightening agent.
Abstract:
Superabsorbents containing a compound of formula (I) where M represents a hydrogen atom, an ammonium ion, a monovalent metal ion or one equivalent of a divalent metal ion of groups 1, 2, 8, 9, 10, 12 or 14 of the periodic table; R1 represents OH or NR4R5, where R4 and R5 independently represent H or C1-C6-alkyl; R2 represents H or an alkyl, alkenyl, cycloalkyl or aryl group which optionally has 1, 2 or 3 substituents selected independently from C1-C6-alkyl, OH, O-C1-C6-alkyl, halogen and CF3; and R3 represents COOM, SO3M, COR4, CONR4R5 or COOR4, where M, R4 and R5 are each as defined above, or, when R2 represents aryl which is optionally substituted as indicated above, also represents H, salts thereof or mixtures of such compounds and/or salts thereof display improved stability to discoloration in storage under elevated temperatures or elevated relative humidity.
Abstract:
The invention relates to a method for producing water-absorbing polymer particles, wherein at least one aliphatic aldehyde or the conversion product thereof has an aliphatic alcohol, an aliphatic amine, ammonia, a hypophosphite, or a phosphite added thereto.
Abstract:
The present invention relates to a water absorbing material obtainable by a process comprising the steps of bringing particles of a non surface-crosslinked water-absorbing polymer in contact with a) at least one postcrosslinker, b)10-1000 ppm, based on the non surface-crosslinked water-absorbing polymer, of at least one Nitrogen-containing water-soluble polymer of which the Nitrogen can be protonated, and c)at least one hydrophobic polymer and heat-treating the particles thus obtained at a temperature in the range from 120°C to 300°C and a method for the production thereof.
Abstract:
The present invention relates to a water absorbing material obtainable by a process comprising the steps of bringing particles of a non surface-crosslinked water-absorbing polymer in contact with a) at least one post-crosslinker, b) 0.1 - 1.0 wt.% of at least one water-insoluble metal phosphate, based on the non surface-crosslinked water-absorbing polymer, and at least one further ingredient selected from c) at least one Nitrogen-containing water-soluble polymer of which the Nitrogen can be protonated, and d) at least one hydrophobic polymer and heat-treating the particles thus obtained at a temperature in the range from 120°C to 300°C and a method for the production thereof.
Abstract:
The present invention relates to a process for producing a water-absorbing material comprising the steps of a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 00C to 1500C and b) heat-treatment of the coated particles at a temperature above 50°C, wherein in step b) the duration of the heat-treatment is chosen that the CS-SFC value of the obtained polymeric particles is at least 10 % of the optimum CS-SFC value, and the water-absorbing material obtainable by this process.
Abstract:
The present invention relates to a process for producing a water-absorbing material comprising the steps of a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 00C to 15O0C and b) heat-treatment of the coated particles at a temperature above 50°C, wherein in step a) and/or b) a coalescing agent is added and the water-absorbing material obtainable by this process.
Abstract:
The invention relates to fine-grained water-absorbent polymer particles with a high fluid transport and absorption capacity. According to the invention, the centrifugal retention capacity (CRC) is at least 26 g/g, the absorption under a load of 4.83 kPa (AUL0.7psi) is at least 23 g/g and the transport value (TW) is at least 15,000 cm 3 s, whereby the transport value (TW) is the product of a fluid transfer (SFC) and wick absorption after 60 minutes (DA 60 ) multiplied by 10 7 and the wick absorption after 60 minutes (DA 60 ) is the quantity of a solution containing 0.9 wt. % common salt that is absorbed by 70 g of the water-absorbent polymer particles in 60 minutes. The water-absorbent polymer particles are held in a circular container with an internal diameter of 6 cm during the measuring process, the bottom of said container being sealed by a screen base with a mesh size of 36 µm and the screen base being in pressureless contact with a solution containing 0.9 wt. % common salt. The invention also relates to a method for producing said particles and to their use in sanitary articles and packaging materials.
Abstract:
The invention relates to a method for the secondary crosslinking of water-absorbent polymers by treating the polymer with at least one secondary crosslinking agent and post-crosslinking and drying the same during or after the treatment by increasing the temperature. Said at least one secondary crosslinking agent represents a cyclic carbamate or a cyclic urea obtained by reacting an amino alcohol or a diamine with a cyclic carbonate.
Abstract:
The present invention relates to a process for producing a water-absorbing material comprising the steps of a) spray-coating water-absorbing polymeric particles with an elastic film-forming polymer in a fluidized bed reactor in the range from 0°C to 1500°C and b) heat-treatment of the coated particles at a temperature above 50°C, wherein in step a) and/or b) an antioxidant is added and the water-absorbing material obtainable by this process.